/ohm/ - Eternal electronics thread

[Anonymous No.1868373]

died thread: >>1861536

>I'm new to electronics. Where to get started?
It is an art/science of applying principles to requirements.
Find problem, learn principles, design and verify solution, build, test, post results, repeat.

>Project ideas:
http://adafruit.com
http://instructables.com/tag/type-id/category-technology/
http://makezine.com/category/electronics/
Don't ask, roll:
https://github.com/Rocheez/4chan-electronics-challenges/blob/master/list-of-challenges.png.png (embed) (embed) (embed) (embed) (embed)

>Principles (by increasing skill level):
Mims III, Getting Started in Electronics
Geier, How to Diagnose & Fix Everything Electronic
Kybett & Boysen, All New Electronics Self-Teaching Guide
Scherz & Monk, Practical Electronics for Inventors
Horowitz and Hill, The Art of Electronics

>Design/verification tools:
LTSpice
MicroCap
falstad.com/circuit/circuitjs.html
NI Multisim
CircuitLab
iCircuit for Macs
KiCAD (PCB layout software, v5+ recommended)

>Components/equipment:
Mouser, Digi-Key, Arrow, Newark, LCSC (global)
RS Components (Europe)
eBay/AliExpress sellers, for component assortments/sample kits (caveat emptor)
Local independent electronics distributors
ladyada.net/library/procure/hobbyist.html

>Related YouTube channels:
mjlorton
w2aew
jkgamm041
eevblog
EcProjects
greatscottlab
Photonvids
sdgelectronics
BigClive

>Li+/LiPo batteries
Read this first: http://www.elteconline.com/download/pdf/SAFT-RIC-LI-ION-Safety-Recommendations.pdf
>I have junk, what do?
Recycle the blue smoke

[Anonymous No.1868384]

i wish i had a shirt with "shutterstock" written on it

[Anonymous No.1868389]

>>1868384
I wish i had safety glasses to protect my hand from being burned by heatguns

[Anonymous No.1868399]

Figured out the kicad thing.

Turns out there is a second ground plane on the bottom which connects all the top ground planes together so kicad was correctly showing no errors and if i had chinks make the board it would work fine.
The problem is only if i make the board myself it wont work because my holes are of course not plated through, which means in my case i need to connect the red ground planes to the green plane with the extra vias i now added
Alternatively this issue could also be solved by soldering the THT components on both top and bottom but i can't be assed to do that.

[Anonymous No.1868407]

>>1868399
Don't call me Chink, Ricist!

[Anonymous No.1868422]

>>1868399
Weren't you ordering the PCB from a manufacturer? As a home-etcher I also run into the "no plated THTs" issue, makes me want to go SMT instead.
As far as settings go, you can probably configure it so there are only solder pads on one side of the PCB, or just use a single-sided board if that's an option. Though single-sided boards are really limiting, not something I'd consider for this kind of project.
Soldering the parts on both sides is an option for components like DIPs and transistors and resistors, but for pin headers and flush pots/trimpots and the like it isn't feasible.

Could try the conductive ink +electroplating method (identical to electroforming but cheaper), iirc you can get fine graphite powder pretty cheap in the form of lock lubricant. Not sure what sort of adhesive to use though. Copper electroplating will also cause the PCB thickness to increase. Also there's a bunch of electroplating additives to change the geometric biases of the plating (e.g. towards/away from sharp edges) which I'm entirely unequipped to talk about. I tried making my own conductive glue once, using house paint mixed with charcoal that I made in a tin can in my backyard over a little propane cooker. The charcoal was too coarse even after I crushed it with a rock on the pavement, and my snot was black for a few days afterwards.
There's also electroless methods like palladium and quite possibly silver too. Never seen anyone use a silver mirror for plating THTs, but it should be a lot cheaper than getting that palladium salt.

There's always THT rivets, but they don't sit too flush and require a tool. If you're doing etching anyhow I'd lean towards a chemical plating method, but if you're routing your traces you may be able to make slight recesses for the rivets to better fit into.

[Anonymous No.1868441]

What do I connect this to, to then attach 2,5mm cables?

[Anonymous No.1868444]

>>1868441

even if you manage to pull the male equivalent off of a PCB, then what? you'll have to solder wires to the male pins. so might as well cut off the connector and solder directly to the wires. but you dont have a soldering iron! then you can get spade crimps. but you dont had a crimper! so, either spend some money or give it to someone who has the tools and knowledge.

[Anonymous No.1868452]

>>1868444
Okay, so just crimp these then I can connect. Thanks.

[Anonymous No.1868518]

Brainlet question.
I have a large infrared heater that was running on 120V.
It's wired like pic related (8 parallel branches with 3 series tubes in each).
I want to run it off 220V so I was going to change it to 4 parallel branches of 6 series tubes.
I was trying to work out the current rating the cable would have to be for making jumpers and I must be doing something wrong.

If they're in series of 3 at 110V then voltage drop across each would be 36V odd so a 500W tube would pull about 13.5A.
Therefore each parallel branch would be pulling 13.5A giving a total current of 8 x 13.5A = 108A?
The input breaker for the unit when it was running at 110V was only 20A so what am I doing wrong?

[Anonymous No.1868537]

>>1868518
Oh wait, it's the series resistance isn't it?

[Anonymous No.1868539]

Everybody knows the old welder-from-a-microwave trick, but what about DIYing a welder with batteries for improved portability? Would 6s (24v) be enough to strike an arc or does it need more volts?

[Anonymous No.1868542]

>>1868539
It's called an inverter, and good luck. That kind of power electronic shit is on the border where it's better to buy than to /diy/. You could try a spot welder tho, with huge fuck capacitors.
>>1868518
Sorry I am confused, is it 500W? If yes then
>p=Vrms*Irms
>500/110=4A and change

[Anonymous No.1868546]

>>1868542
And if you actually measured 20A at the breaker then:
>P=20*110
>2.2kW
If the rated power is 2.2kW then for the same power at twice the voltage you would need 4 times more resistance.
If you use Ohms law and P=V*I and a bit of algebra you'll reach the conclusion that
P=V^2/R.

[Anonymous No.1868547]

>>1868518
>a 500W tube
Is the tube 500w or the entire heater 500w? If each tube is 500w that would make the whole thing 12000w, which no 120v circuit I've seen is even remotely capable of handling.
Just take the total power of the entire heater and divide by 220 to get the amps you need (assuming it's a resistive load which heaters usually are).
>>1868399
If you don't have plated through holes how can you expect to have plated vias? I suppose you could drill a hole and stick a wire through.

[Anonymous No.1868548]

>>1868518

you doubled the voltage and also doubled the resistance, so the current is the same as before.

>>1868539
>Would 6s (24v) be enough to strike an arc or does it need more volts?

the reason you can weld with a modified MOT is coz it can put out 500 to 1000 amps at 1-2V. your shitty batteries aint even close.

[Anonymous No.1868549]

>>1868547
>have plated vias?
they aren't plated, i connect them manually by sticking a wire through and soldering on both ends

i also have a special pcb riveting tool coming in the mail so hopefully that will replace the tedious soldering

[Anonymous No.1868558]

>>1868547
Each tube is 500W
So now I'm thinking if it was one tube getting 110V it would draw 500/110 which is 4.5A so resistance of a tube is =110/4.5 = ~24.5 ohms
So if 3 are in series it'll be about 73.5 ohms.
Then 110/73.5 = 1.5A through the series.
So the total current would be 8 parallel branches with 1.5A each = 12A

[Anonymous No.1868566]

>>1868558
If each tube is rated at 500W then you are not running it a full power if you measured 20A at the input. Something is wrong here, either you are not being clear or I'm missing something. Did you actually measure 20A?

[Anonymous No.1868570]

>>1868548
>the reason you can weld with a modified MOT is coz it can put out 500 to 1000 amps at 1-2V
Surely it doesn't need to be that much. The welders I've looked at advertise 100-200A at full power, which is totally doable with batteries. I assume that is an average current, I don't know if it needs to spike higher than that to start or something.

[Anonymous No.1868577]

>>1868570
>The welders I've looked at advertise 100-200A at full power,

those are stick welders. MOT welders dont use anything other than current to weld.

[Anonymous No.1868580]

watching thew mill drill precisely centered tht holes is downright orgasmic

[Anonymous No.1868582]

>>1868570
>The welders I've looked at advertise 100-200A at full power,

those are stick welders. MOT welders dont use anything other than current to weld. if you wanna do stick, two car batteries in series work fine.

[Anonymous No.1868583]

>>1867348
>using an entire inverter IC
Speaking of inverter ICs, I think this is pretty clever use for a 74HC14.
https://www.radiolocman.com/shem/schematics.html?di=150510

[Anonymous No.1868597]

>>1868582
>those are stick welders
Yes, that is what I am interested in. I see now that there are plans for making both spot and stick welders from microwaves, so maybe that wasn't obvious.
>if you wanna do stick, two car batteries in series work fine
That's helpful, makes me think I'm on the right track.

[Anonymous No.1868603]

>>1868566
No I didn't run it.
I initially assumed that since it's a 500w tube and 3 in series would have 36 volts across them that they'd pull 13 odd amps but I never took the resistance into account which would reduce the current

[Anonymous No.1868621]

>>1868603
500 watts * 24 tubes = 12000 watts = 41000 BTUs = enough to heat a typical 900sqft house. Alternately 12000 watts / 120 volts = 100 amps = literally all the power that typical 900sqft house is capable of receiving from the power company (yes, I know many houses have 200A hookups but whatever.)
I see three possibilities.
1. You're interpreting the specs wrong. Can you post a pic or datasheet or something?
2. As other anon suggested, the tubes are rated for 500w but are run at much lower power for better longevity.
3. You've gotten your hands on an ABSOLUTE UNIT of a heater and will probably burn your house down.

[Anonymous No.1868622]

[Anonymous No.1868625]

[Anonymous No.1868627]

[Anonymous No.1868629]

[Anonymous No.1868661]

If I have an E-scooter with a lead-acid battery (sorta like pic related) and I swap it out for an 18650 pack, will I have to replace the charger/controller?
Is it worth it for a 24volt / 100watt motor?

[Anonymous No.1868664]

>>1868603
>I never took the resistance into account which would reduce the current
No it's not that. You need 2 (Only two!) variables to solve these things, Voltage, Power and current. If you give all three the results must check out because then there is nothing to solve.
>>1868518
>The input breaker for the unit when it was running at 110V was only 20A so what am I doing wrong?
This says the current is less than 20A for the whole thing wired the way you said, so each one of those legs can get 2.5A without tripping the breaker (20/8). With 36V across each element that gives a power of 91W (2.5*36) per tube not 500W. With 91W the resistance (While hot!) would be about 14. something Ohms (R=p/i^2 => 91W/(2,5*2,5)=14). The total resistance for the 110V would be then 5.25 Ohms (14 ohms* 3/8 tubes). The math checks out now because 110/2,5 = 20 somethings amps = your breaker rating.

Now your idea will work, because if you make 4 legs of 6 the total resistance will be 21 Ohms (6*14 /4). Because as I said here :
>>1868546
>for the same power at twice the voltage you would need 4 times more resistance.
>Tl;dr
Your idea is correct but I have no idea where you got 500W and a billion amps. If you just wire 4 legs of 6 it'll work.
>>1868661
>https://enerdrive.com.au/2017/11/29/can-charge-lithium-battery-lead-acid-charger/
Most likely not gonna work.

[Anonymous No.1868669]

>>1868664
It'll work regardless of the actual resistance value btw, as long as they are all the same and assuming it ran with the 20A breaker ok. The new current rating will be half of the old one.

[Anonymous No.1868673]

>>1868627
what the fuck is he sitting on

[Anonymous No.1868674]

>>1868673
mutt wheelchair with vinyl shitting cushion.

[Anonymous No.1868675]

>>1868664
>4 times more resistance
isn't 4 times more = 5 times as much?

[Anonymous No.1868677]

>>1868675
2 is 1, and 1 is none.

[Anonymous No.1868684]

>>1868675
Uh not, exactly 4. I rounded some stuff because I suck at doing math on my head.
>P=V^2/R

[Anonymous No.1868685]

Are vintage stereo amps (70s and 80s) worth it, or are they just a meme? Especially when you take into account the reliability and tolerances of the parts manufactured in their day compared to now.
My Grandfather dug up an old Soviet stereo amp and is currently "restoring" it - tracking down old parts, components, etc. to make it fully functional again. The primary issue is that the internal parts (transistors, capacitors, etc.) are blown and are hard to track down, due to them being old/no longer manufactured, or the parts are either not matching or reproductions and no longer the same. A lot of this crosses over into Audiophile territory - trying to hunt down the exact transistors that were matching from the factory, as the reproduction parts produce different results that aren't ideal. And a lot of this got me interested in getting my own vintage stereo amp, and whether they're truly better than today's digital amps or just a hipster audiophile meme

[Anonymous No.1868687]

>>1868677
ok, schools are closed forever

[Anonymous No.1868688]

>>1868685
It's audiophile crap

[Anonymous No.1868689]

>>1868687
Two birds, one stone. See?

[Anonymous No.1868690]

Also, continuing from the amp - are there any good, reputable sites for getting rarer components for vintage stuff? I'm skeptical of ebay in case of false advertising or the parts are not as described. I'm hunting down soviet transistors (part no. KT808A) that are matched from the factory.

[Anonymous No.1868697]

>>1868690
Use modern equivalents to get it running again and take your time to source the originals. Ebay is your best bet in this case.

[Anonymous No.1868698]

>>1868697
Time isn't so much the issue, the project's been going on for a year with the intent of doing it right rather than doing it fast. The issue with using modern stuff is that it's not quite the same - the whole charm and sound quality from vintage stuff (amps, synths, etc) is that the parts that were made in that time had different tolerances, manufacturing methods, and materials; because the quality wasn't as consistent, it created a variance in each product down to the part that gives it the coveted vintage sound and feel. Modern components make it pointless, especially if you just discard them afterwards once you have the desired vintage ones.

[Anonymous No.1868706]

>>1868698
That's all true, but are you going to use the amp to listen to a vinyl record collection or modern digital sources?

[Anonymous No.1868711]

>>1868706
It's my grandfather that will be using it - I'm just along for the ride because I like electronics and vintage stuff.
He'd be doing a mix - he's pretty tech savvy and uses computers + listens to music digitally, but also has some bonafide vinyls and record players he still uses which he bought from its respective era.

[Anonymous No.1868719]

>>1868711
In that case you could probably find acceptable components in Kenwood or Pioneer amps from the same era. One thing you'd probably have trouble replacing 1:1 is old capacitors, for obvious reasons.

[Anonymous No.1868728]

>>1868583
oh neat

>>1868603
So you know, you can't just measure the resistance of an incandescent lamp and treat it as a constant, those lamps have a much lower cold resistance than their hot resistance.
Where'd you get the "500W" rating from anyhow?

[Anonymous No.1868745]

>>1868664
>>1868728
Sorry, the tubes themselves say 500w on them.
Pic related is from the manual from the machine I took the heater out of.
It was being used to head large pcbs from the bottom in a hot air rework station

[Anonymous No.1868748]

>>1868745
Then I'd say that the tubes themselves are meant to run on 120VAC and are being undervolted. Who knows how much power each lamp is drawing in the current configuration, but it's probably 30-80W each.

[Anonymous No.1868750]

Does anyone have any infographic or any recommendation for good budget multimeters and soldering stations?

[Anonymous No.1868754]

anyone got experience with precision water heaters?
I'm thinking of building my own sous vide cooker from a raspi and some sensors, so it only needs to be able to get maybe 5 gallons of water up to ~165F tops
would I be better off buying a prebuilt one, or should I try to build it myself?
seems pretty simple, just wrap some bare metal wires around an insulator and waterproof it, but that also seems like a good way to die

[Anonymous No.1868755]

>>1868748
Yeah, that's what I'm trying to figure out.
If I'm reconfiguring it, I'm gonna have to make wire jumpers so I wanted to work out the max current I'd be pulling through the wire to make sure I use a large enough cable

[Anonymous No.1868759]

>>1868754
Buy a proper heating element and controller unless you want to trial & error your way through debugging/failsafe features.

[Anonymous No.1868760]

>>1868750
I got this station from ebay about 3 years ago and never had any issue with it.
Mind you I've only used it for through hole and some larger smt components but I've not even changed the tip since I got it and I've made thousands of joints with it.
Depends what functionality you want in the multimeter but I've a cheap as fuck uni-T ut30c that seems accurate enough in voltage and resistance anyway.
I did melt the original cables off it by pulling 8 amps through it though

[Anonymous No.1868773]

>>1868745
That makes a lot more sense. Probably using oversized bulbs at lower voltage was cheaper than purpose-built infrared bulbs.
>>1868755
You're gonna have to measure, or else guestimate since the bulbs are probably not specced for the reduced voltage.
Since you are doubling the voltage but putting twice as many bulbs in series, it should be safe to assume they will get the same voltage, current and power per-bulb. Since the entire setup evidently used to function on <=20A at 120v, it should function at <=10A at 240v. Divide that by the number of strands (20/8=10/4=2.5) to get the current per-strand. That should give you an upper bound, the actual current could be way less. Make sure your insulation and clearances can handle the higher voltage.

[Anonymous No.1868775]

>>1868759
Yeah, that's what I figured
are there any out there that you'd recommend?

[Anonymous No.1868781]

>>1868775
I don't own any of this, but this stuff should work okay.
Controller: https://www.amazon.com/Inkbird-Temperature-Controller-Controlling-Fermentation/dp/B07PVBG8K1
Heater: https://www.amazon.com/Precision-Premier-Line-742G-Submersible/dp/B000BDB4UG

[Anonymous No.1868796]

>>1868781
that's pretty much exactly what I wanted to build
kinda takes the fun out of it, but I guess it ends up being less expensive than most of the sous vide cookers on the market, and I still have more control than they give you
thanks

[Anonymous No.1868801]

>>1868755
Hasn't this been solved already? If you double the voltage and quadruple the load resistance you get half the current and the total power remains the same.

[Anonymous No.1868831]

I bought a Direct Logic 06 PLC which I've used in classes before and I found relatively cheap. Wanna experiment with it and potentially use it for some projects. My problem is the software...The DirectSOFT6 license is $417 from automation direct. This is like 4x more than I paid for the PLC itself. Anyone know if/where I can find the full software for free? Tried the usual suspects like TBP. Absolutely nothing. I'll pay it if I absolutely have to but I wanna scour the internet first and be absolutely sure I can't find it elsewhere.

[Anonymous No.1868850]

>>1868754
Immersion heaters for mains voltage are like $5 each, no reason to attempt to make your own. Then a PID controller will run you maybe $25-50, and those things are designed to run off mains and have all the requisite power supplies, and don’t need an external mcu or computer. Not sure how easy it is to control them externally for programmed temperature profiles, but it should be possible. They have some buttons and an LCD on the front for simple control. I’d also include a little aquarium pump so the water can move about and stop a temperature gradient between the element and the temp sensor. Those PID controllers also have integrated thermocouple reading hardware, probably common thermistors too. Will probably need to buy the temp sensor itself, but that’s cheap.

[Anonymous No.1868862]

Why aren't transconductance amplifiers taught in school?
My advanced electronics classes covered all kinds of op-amp configurations, but OTAs were never mentioned.
Granted that OTA's aren't quite as versatile as op-amps, but when you need them they're super handy.

[Anonymous No.1868863]

>>1868862
because what you're supposed to learn is how to figure it out for yourself?

[Anonymous No.1868868]

>>1868863
How are you supposed to figure them out for yourself if you're never even told about their existence?

It's like being taught how to program without ever being told about dynamic memory allocation.
Yes, you can write your programs with nothing but statically allocated memory, but you can do so much more with dynamic memory allocation.

[Anonymous No.1868902]

>>1868868
Because that's experience, not basic theory? Is this the first component you've come across outside your degree? Have you bothered to look through digi-key just to see what's out there? How much hand-holding do you need?

[Anonymous No.1868933]

>>1868902
>Because that's experience, not basic theory?
Bitch what? Dynamic memory may be a basic building block of programming, but it's a very complicated topic.
I wouldn't trust anyone who taught themselves how to use dynamic memory because there's so many pitfalls in how to use it that cause hard to fix bugs if you don't know what you're doing.

>Is this the first component you've come across outside your degree?
No, why would you assume that?
>Have you bothered to look through digi-key just to see what's out there?
Do you learn all your electronics knowledge through datasheets? Because that's a terrible way to learn basic theory.
Datasheets are for telling you the specifications for a specific part and maybe giving a few example circuits.

>How much hand-holding do you need?
Is teaching how op-amps work handholding?
Is teaching the 3 basic transistor amplifier topologies (common base/emitter/collector) handholding?
Is teaching diodes handholding?
Is teaching how transformers work handholding?
Is teaching how resistors/inductors/capactors handholding?
Should professors just throw Maxwell's equations at their students and tell them to figure the rest out on their own?

[Anonymous No.1868942]

>>1868933
....retard, this started off complaining about not learning from _professors_. What the fuck are you talking about self-taught for? Desperately needed strawman?

[Anonymous No.1868948]

>>1868942
Who else is going to teach you about electronics?
I can't imagine an employer teaching you about OTAs.
That leaves self education.

>Desperately needed strawman?
Mate, I've seen stronger arguments from strawmen than what you've presented.

[Anonymous No.1868949]

roll

[Anonymous No.1868956]

Is there a type of annular sensor I can buy for measuring the radial compression of a ring? annular load cell, etc turns up nothing.

>>1868580
that's sweet but i think your bit is dull

[Anonymous No.1868965]

>>1868956
Fill it with oil and pipe it to a pressure sensor?
IIRC load cells aren’t good at compression, just tension, but usually that’s just a matter of perspective and changes based off how you arrange the geometries of your parts.

[Anonymous No.1868967]

>>1868956
Try a buttplug.

[Anonymous No.1868973]

>>1868948
The conversation started out as someone who graduated with an electrical engineering degree. You descended into talking about fucking passives. Please go fuck off with that reductive noise.

[Anonymous No.1869010]

>>1868973
>Professors teach about voltage amplifiers, current amplifiers, and transimpedance amplifiers
>but don't fucking teach about transconductance amplifiers, that's handholding
This is you.

[Anonymous No.1869030]

>>1869010
Incorrect, you seem incapable of understanding what I said. I shall spell it out further since you can't get over the minor hurdles.
Professors teach a subset of all EE knowledge, and you are expected to generalize, and learn on your own post gradutation. You can also learn from mentors on the job, which I didn't even bother explaining, because i wasn't trying to explain all the sources of information, only that professors aren't responsible for teaching you everything. They cannot, there isn't enough time. They are expected to pass along sufficient knowledge and skill that you can understand industry standard documentation. Apparently you didn't learn this at all.
Apparently you think EE is "Everything you learned" + OTAs, not understanding how big the field is, and how little material is covered.

[Anonymous No.1869048]

>>1869030
Anon, transconductance amplifiers are literally one of the 4 basic kinds of amplifiers which relate voltage and/or current
This isn't some obscure topic, it's just as fundamental as inductors are to passive components.

[Anonymous No.1869049]

>>1868862
Non-meme answer: because they're barely used in the real world. Usually it's either textbook op-amp circuits, transistor circuits, or DSP, with some weird shit around RF circuits. Also dedicated voltage-controlled-amplifier ICs and mixers, and digipots, in the case that DSP isn't being used for voltage-controlled amplification/signal mixing. Only in the audio effects world do OTAs get a significant amount of use, and the common circuit blocks used by audio effects are quite far removed from the rest of analog electronics, so to learn any of them, including OTAs, you'd need to take a course specifically focusing on audio circuit design.
t. guy wants to implement effects pedals with DSP on an MCU

[Anonymous No.1869050]

>>1869048
memristors are one of the 4 elementary passive circuit elements, how didn't you learn about those in high school alongside caps, coils, and resistors?

[Anonymous No.1869059]

>>1869048
Confused still. I'm not saying they *shouldn't* be taught, im saying any given curriculum cannot teach everything, and the point is to absorb enough information that you can understand. Maybe you failed at this.
You say they are fundamental, but they are only if you are in that area of the field. I spent way more time studying EM fields and semi-conducting materials, mostly because I wanted to.
First job was working with FPGAs, custom ASICS, and PCB design, which I never learned that in school (some did, I didn't take those classes, was more curious about photonics).
Never touched amplifiers outside of school, and that was 20 years ago now. You don't seem to grasp how big the field is.

[Anonymous No.1869064]

>>1869048
OTAs are seldom used and therefore it's not worth teaching about. You'd never see an OTA in pretty much any commercial or industrial piece of equipment. It's literally only used by audio people doing /diy/ synths and stuff like that. It isn't even used in professional audio applications where everything is typically done digitally. In short OTAs are basically obsolete parts. There's no sense covering them in school, if you have a good grasp of electronics you shouldn't need to be taught how they work you can read the datasheet for the LM13700 which explains their operations in more than enough detail and provides internal schematics and whatnot. If you need a teacher to have taught you this you're not a very good engineer.

[Anonymous No.1869065]

>>1869059
reminds me of that one guy in an eevblog comments section who worked in a crystal factory (i.e. oscillators) and had a whole slew of extremely specific information about how the best crystals are made, and how cheap crystals differ from properly made ones, and how shocking a crystal resets its drift, and all this incredible info. was on a video about dremelling apart a crystal oscillator to see the internals. incredibly specific stuff, but possibly useful for those of us trying to select crystals for a project where quality matters.

[Anonymous No.1869074]

>>1869050
They were mentioned at least.
No effort went into learning them though because we're still trying to learn how to make them.
Meanwhile OTAs have been around for ages.
We actually did learn about gyrators in detail though.

>>1869049
>because they're barely used in the real world.
While I get what you're saying, I was taught about plenty of things that are rarely used in the real world, like jfets, and lots of the circuits we built in the labs used crusty old ICs which aren't in production anymore.

>>1869059
>Confused still.
You sure do love your ad hominen, I think you've done that in almost every post.

>im saying any given curriculum cannot teach everything,
No shit
>the point is to absorb enough information that you can understand
Right, I don't see how that precludes introducing the concept of an OTA alongside all of the op-amp stuff.
It doesn't have to be a super in-depth lecture, just mention it and give the students the basics, like half the other shit that we briefly touch on in class.
>Maybe you failed at this.
More ad hominen, you really can't help yourself
>I spent way more time studying EM fields and semi-conducting materials
And I spent more time on digital logic and processor design.
I still had to take advanced classes on analog electronics, AC power, and loads of other stuff.
>First job was working with FPGAs, custom ASICS, and PCB design, which I never learned that in school
All of that, except ASICs, is required coursework in my degree program.
>Never touched amplifiers outside of school, and that was 20 years ago now.
Ok, and I won't touch half the stuff I learned either, but like you said, the point of the classes is to educate you about a wide variety of topics so you are familiar with them.
>You don't seem to grasp how big the field is.
More ad hominen.
I'm not talking about entry level electronics classes, I'm saying that I've taken everything from intro to electronics to the graduate level courses and OTAs were never mentioned.

[Anonymous No.1869083]

Shh, nobody tell the autist about current feedback op-amps the only op-amps that have 1GHz+ gain bandwidth products. Nobody tell the autist about current differencing Norton op-amps. Forget op-amps even, nobody tell the autist about Heterojunction bipolar transistors, or MESFETs, or negative resistance oscillators like Gunn diodes.
Nobody tell the autist about all the fucking weird exotic components out there that you never learn about in school. He doesn't get it.

[Anonymous No.1869084]

>>1869074
Not a single thing you've posted forwards your case that OTA's should be taught, at all, and demonstrably it's false as you weren't.
Where are you going with this? All you've done is put words in other people's mouths and completely misunderstood the main counter-point: Not everything is taught in every program, and even within a program, people don't learn the same stuff once you hit electives.

[Anonymous No.1869093]

>>1869083
>current feedback op-amps
That's just another variant of the transimpedance amplifier, which is taught by almost every professor
>Norton op-amps
That's another kind of transconductance amplifier.
>negative resistance oscillators like Gunn diodes.
Really not that complicated

>all the fucking weird exotic components
>Implying that OTAs are exotic

[Anonymous No.1869099]

>>1869084
>All you've done is put words in other people's mouths
He says as he repeatedly puts words into the other anon's mouth.

>completely misunderstood
You don't seem to understand that anon's argument either.

[Anonymous No.1869120]

regrets? only one: wish i'd spent MORE time engaging in fruitless arguments on 4-chan.

[Anonymous No.1869128]

Well, all the components arrived for me to make my red flashing LED. The original idea was to make a fake alarm light and hide the switch somewhere under the dash. But I got to thinking: why not make a real alarm?
Basically I want to wire 6 magnetic reed switches to the six doors. When one of the doors opens, it triggers a 120dB speaker to go off. Do I need to wire the switches in series or parallel? For a kill switch for this reed switch alarm, can I hook it up to the same kill switch for the blinking light? I was thinking maybe having a 7th reed switch connected to one of the door lock levers because they move when I lock the vehicle so it might be easier or better to use that as the main switch for the actual alarm bit. Or maybe both the speaker and the light, I'm not entirely sure. The only problem I see is that say someone does open the door while the alarm is armed, if they shut it, the alarm goes off. Which would kind of defeat the purpose, at least partially. One problem I can think of is trying to arm it while getting out of the vehicle. So that's the main reason I was thinking of using the lock lever as the switch.
Would I need another 8-pin Dip to drive the speaker? I ask because I had to buy 10 sockets and 10 boards so I'm trying to come up with some ways to use them. I only have capacitors, about 10 of 10 different sizes, but I can get whatever components I need for this.
I guess I could just buy a professionally made alarm kit, but where's the fun in that?

[Anonymous No.1869129]

>>1869128
Ah shit, I was just thinking, if someone used a Slim Jim or something similar to unlock the vehicle, the alarm would turn off. So that spot for the switch for the speaker is a no-go.

[Anonymous No.1869132]

>>1869120
Do radio waves turn you into a tranny?

[Anonymous No.1869135]

>>1869132
o fuk its 5g
there's a bee joke here isn't there

[Anonymous No.1869137]

>>1868580
no it's not, the bit is new and it goes through the pcb like butter

[Anonymous No.1869146]

>>1869135
>joke
No jokes here, only reality.
https://www.youtube.com/watch?v=ppj3gqUTt9E

[Anonymous No.1869153]

>>1869146
no i've seen a bit of glasslinger, entirely uncanny
i was just wondering if there's a
>5g makes you trans
>5g is killing bees
>the minecraft bee is trans
circle of memes to be had

[Anonymous No.1869160]

>>1869153
5G is making our bees trans, causing a spike in bee suicide rates.

[Anonymous No.1869168]

>>1869160
close enough

[Anonymous No.1869184]

An interesting /ohm/ related thing happened in the town next to mine.
So basically a father and his two sons went to check on a submersible water pump they had running in a lake next to their house, and the next day a relative of this family found them all floating in the lake, face down.
And i am trying to figure out how the fuck does that happen. The water pump which achieved this multi-kill had a short, but the problem here is, unlike in the movies, if you throw a toaster in a bath tub there isn't an electric storm happening, there will just be a small short between the live and neutral and thats it. The only way to get yourself zapped is to grab a live wire or live casing and touch the water, where the only path between the two is your body. But skin has very high resistance so there will always be an easier path between the live and ground, like through the water on your clothes and such.
So dad grabs the live wire, turns into a statue, son grabs dad to help, gets medusad as well, and the third son is dumb enough to complete the daisy chain?
So fucking weird. mains aren't even that strong, it's just shitty 230V

[Anonymous No.1869185]

>>1869184
guy picks up metal pump, electricity goes from the pump in his hands, down into his chest, through his heart, and continues down to earth. son jumps in and grabs his father and leans back holding him against his chest, electricity now goes through his father and into his chest and heart, then down to earth. second son witnesses the death of his father and brother and inhales water.

[Anonymous No.1869186]

>>1869184
black eels are very dangerous

[Anonymous No.1869196]

>>1869184
Usually he touches something live, can't let go of it screams for help, the other person tries to pull him out and gets shocked too.

[Anonymous No.1869197]

>>1869196
>screams for help
haha funny meme friend
i see you never touched a live wire
https://www.youtube.com/watch?v=bkw5mL23iLk&has_verified=1

[Anonymous No.1869198]

>>1869197
either the shock stuns/kills you, or it just hurts/causes non-critical muscles to spasm. in the latter case, screaming can certainly happen.
t. had 2 mains shocks

[Anonymous No.1869200]

>>1869198
i have seen COUNTLESS videos from chinkland of workers touching live wires and they always turn into statues
blocks of marble cannot scream

[Anonymous No.1869201]

>>1869197
I have touched wires but fortunally never had the situation where my grip got stuck or shit went through my heart. Usually from the hands to the arm (which was touching something) or between fingers. And you can clearly see the bovine screaming.
>t. person you quoted
I wasn't saying like:
>touches wire
>grip gets stuck for 10 minutes
>during said 10 minutes dude screams for help
I was saying literaly
>touches shit
>scream, gets stuck and non-responsive
>other dudes pulls him and gets shocked
>time passed, 5 seconds
Anyhow, seeing your kid T-posing while fixing a pump may be alarming enough without a scream.

[Anonymous No.1869202]

>>1869200
yeah, because that's the former case, stunning or flat-out dying
but "i see you never touched a live wire" implying you can't scream in any possible case (even extremely light non-lethal shocks) is flat-out wrong
might as well be saying "lmao, this pleb hasn't suffered a lethal shock before" if that isn't what you were implying

>>1869201
>seeing your kid T-posing while fixing a pump
this made me laugh more than it should have

[Anonymous No.1869221]

Any projects for a decent usb microphone?

[Anonymous No.1869357]

>>1869221

yes, walk into thrift store with four $1 bills and walk out with a Band Camp or Rock Band USB mic with a nice long cord. enjoy great quality mic'ing.

[Anonymous No.1869396]

>>1869146
I blame J. Edgar Hoover.

[Anonymous No.1869399]

Electric organ outputs no sound, either amp or headphones.
Looks like IC501 a 5V regulator blew and fried the the IC's I marked in red, solder on the underside is dark brown.
Also the diodes circled are completely black.

My guess is change IC's, diodes and we're probably good to go, right?
I've done this many times but I've never seen diodes affected after a voltage regulator blow.

[Anonymous No.1869404]

>>1869399
The diodes

[Anonymous No.1869430]

not sure if this is for /ham/ or for this thread.
I'm about to buy LoRa modules because I've read that they have great range. now, people use them with 0.5mW, or 0.25. but, I'm curious if I could increase wattage to like 5 watts and get even more range? couldn't find anything about it online. also, I know it's illegal, but I don't really care (just wanna test it so I doubt I'll get in any trouble)

[Anonymous No.1869436]

>>1869430
>LoRa modules
You gonna play some BBS door games?
LORD and Pimp Wars at a blazing 9600bps?

[Anonymous No.1869442]

>>1869404
Pic won't upload don't know why.

[Anonymous No.1869461]

Hi /ohm/,

Had some basic EE classes, but it was all theory apart from hand-winding a coil.
Here I am now, trying to make a phone charger (Android) for use while bicycling.
The bicycle dynamo says "6V 3W" on it, which seems true when it is connected to the lights, but gets up to 30V when unloaded, why is this? (AC voltage measurement, this is RMS by default right?)
Found some schematics, ordered some components, most importantly: a buck converter and a linear voltage regulator, to test both approaches.
I assembled like in the schematic, where I kept everything the same except the blue component I tried both these options.
The system works and charges my phone when applying 12V DC to the input.
On my bike, the phone says it's charging really shortly (1-2 seconds) and then stops charging. Usually, when the phone has stopped charging, the voltage over the 2200 uF cap is above the rated 16V, so I ordered a 30V version, would this be better?
Should I take an entirely different approach? Tips?

[Anonymous No.1869470]

>>1869461
Try 15k resistors between D- and 5V, and D+ and 5V before the USB socket.

[Anonymous No.1869473]

I have run out of ideas here. I need to measure the op current from a modified smps, the op is ac at 30khz and current 10amps.
Have an ebay dc current/volt meter, the current viewing resistor designed to give 75mV at 50 amp but cant be rectified cause voltage to small.
Tried ct into bridge rec. of 4 x 1n4148's with 1k pot but op is not linear.
Will a precision rectifier work ie be linear, accuracy should be at least half amp.??
Any other ways to measure this?

[Anonymous No.1869474]

>>1869470
I think this is only relevant for iPhones, as the phone did charge normally when connected to 12V DC. I connected the D+ and D- lines, apparently Androids recognise this as a "charge only" device then.
Is this what you meant?

[Anonymous No.1869480]

>>1869436
no, I'm going to send sensor information

[Anonymous No.1869499]

>>1869474
>Samsung devices require 1.2V voltage on both D+ and D- data lines, see the schematic. The R1/R2 voltage divider is providing the required voltage on the D+ and D- pins of the USB connector to be recognized as Samsung native charger. That's it. The only issue is that completely discharged Galaxy Tab battery might draw even more than 500 mA from the USB port, when the USB 2.0 specification limiting the maximum current load to 500 mA. USB 3.0 specification makes improvement here and increased the maximum current to 900 mA. The divider resistor values are not critical as far the divider ratio remains the same, i.e. 0.24 or closer.
from http://www.obddiag.net/usb-power.html

[Anonymous No.1869613]

>>1869430
Definitely a question for the hams. IIRC LoRa has a bunch of standards in place to stop individuals from hogging the bandwidth, and transmitting on a higher power would likely interfere with this.

>>1869473
Precision rectifier with an op-amp and two diodes should work just fine. Turn it into a voltage follower circuit and just measure the DC value. Also lmao at noscope pleb.

[Anonymous No.1869650]

>>1868373
rolling for challenge

[Anonymous No.1869968]

>>1869613
This is the trace at pin 15 on the pwm controller my man lmao.
Im wondering if a current probe type circuit might work as they have to be very linear.

[Anonymous No.1869976]

>>1869968
So long as you use a topology that prevents the op-amp from entering saturation you should be fine. I think EEVblog has a video on that kind of ideal rectifier.

[Anonymous No.1870082]

How do I do this? I bought an ebike for very cheap because it's a pedal assist type bike
The motor only turns on when it detects that that you're pedaling, as it detects the movement of the pedal bracket. I figured that if I simply buy a new speed sensor and fool it by attaching it to my wheel instead (which obviously spins around regardless of if i'm pedaling or not) so i could practically turn it into a legitimate ebike.

I still don't want to lose the original pedal assist functionality so my question is, how do i go about making a switch that chooses between the bracket sensor and the pedal sensor? the cables used are the ones shown in the pic, i think it's called a 3 pin SM JST (not 100% sure about the wire colors, just took what i got from google to make the pic real fast)

[Anonymous No.1870093]

>>1870082
if there are 3 wires you can get a 3 pole double throw switch, then hook the two sensors to either side and the output to the common poles. You could probably do it with a dpdt switch with shared ground if you knew what you were doing.
Do you have a plan for stopping? If it was previously controlled by pedaling and you rig it to think you are always pedaling it seems to me it will just keep accelerating.

[Anonymous No.1870103]

>>1870093
Once any brake is pressed, the motor always automatically turns off. There's a built-in killswitch, so to speak.

Also I suppose it doesn't have to be a toggle switch, a top-down button would work just as well because then I'd return to normal mode once I let go of the beast mode button.

Can you elaborate on the shared ground thing?

[Anonymous No.1870125]

>>1870103
>Can you elaborate on the shared ground thing?

if you had some basic electrical knowledge, and a good idea of what the 3 wires are doing, you could avoid switching all 3 wires, and switch just 2, or even just one. but you dont, so dont take any chances and get a 3-pole double throw switch. should have 9 pins on the bottom.

[Anonymous No.1870128]

>>1870125
Thank you!

[Anonymous No.1870155]

>>1869461
>but gets up to 30V when unloaded, why is this?
Motor generators (and generators in general) have some minimum required load to maintain regulation
How it behaves without regulation depends on how output voltage is generated but in most cases voltage goes up and just using higher voltage rating capacitors is not good idea
A solution to this is in most cases -just adding dummy load resistors to maintain some load even if smartphone or LED is disconnected.

[Anonymous No.1870158]

hi, can I get electrocuted by voltage or amperage of an external battery (normally used for smartphones)

[Anonymous No.1870161]

>>1870155
>ust adding dummy load resistors to maintain some load

in series with a zener so it's not wasting power continually, but only when unloaded.

[Anonymous No.1870178]

>>1870125
This OK?

[Anonymous No.1870230]

>>1870178

nope. that looks like a temporary pushbutton, like a doorbell. you have to keep pushing it to work. what you want is a rocker, like a light switch, that stays in position after you flip it.

[Anonymous No.1870240]

>>1870230
>that looks like a temporary pushbutton

Go study up on what 3pdt means, and in the meantime stop posting out of your ass.

[Anonymous No.1870256]

>>1870240
>Go study up on what 3pdt means
3 poles, double throw
It does not indicate if switch is latching or momentary or if it is on-off-on or on-on (being pushbutton it should be on-on)

[Anonymous No.1870263]

>>1870230
It could also be a toggle switch that keeps the last position until pushed again.

[Anonymous No.1870264]

>>1870256

You are correct. However, that switch is for applications like guitar boxes that you stomp once and it changes state until you stomp again.

[Anonymous No.1870274]

>>1870264
This. It's a pedal for some guitar shit and is toggleable, so it's either down or up.

[Anonymous No.1870406]

>>1869976
Its funny, as i increase current the voltage on the current viewing resistor goes up then down then way up as op current is slowly increased where the rectified volts from the CT increases smoothly and almost linear, the response curves up at the high end with 10 actual amps=16 amps on the panel meter I want to use. I need to somehow compensate to pull down the curve at the high end.

[Anonymous No.1870407]

>>1870406
there shouldn't be any curve on the op-amp at all. post circuit?

[Anonymous No.1870431]

I want to learn electronics because it seems a cool hobby. I'm reading your books, but I also want to try and experiment with the things I read: what equipment do I need?

[Anonymous No.1870456]

>>1870407
Sorry should have been clearer, atm I am testing ideas with image rel. and a current transformer. The pic related outputs the weird up down up voltage as the current is increased, the ct is fed into BRec and trim pot as said above, the ct voltage isnt linear at the upper range (fsd of the panel meter I want to use is 50amps at 75mV)
so for a current of 10amps the meter reads 16 amps

[Anonymous No.1870460]

>>1870456
also to be clearer the CT and ammeter resister are in line with the transformer before the output shockley's I will only need the dc output to indicate op voltage-only drawing power directly from the trafo.

[Anonymous No.1870474]

>>1870431
Find an application of electronics you find interesting and read everything you can. Find online hobbyists and learn from they're work. become familiar with a range of components. Get a free simulator to get confident with basic equations vir potential dividers etc and the rest will follow as you need.

[Anonymous No.1870506]

>>1870474
Thanks. I've been reading the first book on the list and it's pretty fun. Analog electronics seems pretty approachable. As for the simulator I was hoping to not use the computer since I already have to use it too much for my taste for literally everything else: I'd like to play directly with components, making easy circuits on those perforated boards and see for myself what happens.

[Anonymous No.1870514]

I found this vape on the roadside. Small dent in the battery.
What can you do with these?

[Anonymous No.1870516]

>>1870514
There was still plenty of juice in it. Is this coil fucked? It would explain why a full vape was on the roadside.

[Anonymous No.1870521]

>>1870516
Can you get a universal charger for all lithium batteries?

[Anonymous No.1870522]

>>1870516
>It would explain why a full vape was on the roadside.

Maybe they hit puberty and decided they didnt want to look like a child anymore, so they chucked it out the window

[Anonymous No.1870525]

>>1870506
Sims are still useful tools, otherwise you’ll need an oscilloscope to see what your circuit is actually doing. Or a speaker and a good ear, or some sort of sound-card scope. Though it depends on what sort of analog electronics you want to do, get a variety pack of resistors, ceramic caps, and probably electrolytic caps too. Then a handful of transistors, both PNP and NPN (BC547/BC557 are pretty cheap), some 1N4148s, some op-amps and comparators (don’t ask me what to use, my LM324s are distinctly obsolete). Then probably some LEDs, maybe some MOSFETs, stuff like phototransistors or piezo discs. Function generator and scope are pretty damn useful though. I’d get a 2nd hand analog scope and a cheap digital function generator from chinaland.

[Anonymous No.1870528]

>>1870521
Yes you can. A simple 50c TP4046 board should be sufficient for this. Don’t solder onto the lithium ion cell though.

[Anonymous No.1870532]

>>1870525
Thank you anon. I'd rather get an oscilloscope than use the PC. I ran a quick search and in my area used oscilloscopes aren't cheaper than new ones from the usual chink sites, so I'd go with the latter: any recommendation? I saw really cheap ones that look like portable mp3 players, but something tells me they're worthless. Still, the bigger models look more powerful than I can handle.
Also, why can't a smartphone be used to generate a function through the audio jack? I mean, after all it generates electric signals, doesn't it?

[Anonymous No.1870536]

>>1868698
>coveted vintage sound and feel
Meaning the shittier fidelity?

[Anonymous No.1870537]

>>1870536
Having warmth isnt "shittier fidelity"

[Anonymous No.1870538]

>>1868384
They have it

[Anonymous No.1870539]

>>1870537
It literally is. What do you think warmth is?

[Anonymous No.1870540]

>>1870539
So you need to introduce artificial decreases in fidelity to get the same soundstage and body as older designs?

[Anonymous No.1870541]

>>1870540
If I wanted "warmth," yes. But as someone who's not an idiot, I prefer high fidelity

[Anonymous No.1870543]

>>1870541
Sounds like "high fidelity" is a misnomer if lifeless and sterile audio is what you get

[Anonymous No.1870544]

>>1870537
not sure if bait. what do you mean by "warmth"? even harmonics? or compression due to sagging?
you can go digital and reproduce any waveform.

[Anonymous No.1870546]

>>1868690
wait, transistors??? for warmth?? you need tubes!

[Anonymous No.1870548]

>>1870543
>lifeless and sterile
You're listening to bad music if you need to fuck up its playback it to enjoy it

[Anonymous No.1870549]

>>1870544
>you can go digital and reproduce any waveform.
Thats good, because we all know that "accurate" listening is fatiguing and you cant do it for very long
Its not pleasing at all to the ears

[Anonymous No.1870550]

>>1870543
>lifeless and sterile audio is what you get
Why would you want to hear your equipment making noise rather than the sound the artist intended? Truly remarkable amounts of cope.

[Anonymous No.1870551]

>>1870549
I genuinely can't tell if this is an ironic post.

[Anonymous No.1870553]

>>1870551
Have you never done critical listening on very high quality equipment?

[Anonymous No.1870555]

>>1870550
Having your audio be pleasant to the ears as opposed to shrill because of mastering made for the general public?
I dont know, why would I want that anon?

[Anonymous No.1870556]

>>1870553
>>1870555
Are you arguing it's better to listen to music on worse equipment? That's hilarious
>mastering made for the general public
>muh special ears

[Anonymous No.1870563]

>>1868539
Do ***NOT*** short-circuit Li+ batteries!

[Anonymous No.1870564]

>>1870543
>>1870550
Not him, and not you, I am another anon, but this is actually an interesting point. The sound the artist intended may already have enough "warmth". It could have been your favorite guitar piece played through a vintage tube amp. Why would you want additional "warmth" on top of the original distortion since the original recording is already pre-distorted for you. You actually need a high fidelity equipment to reproduce the original warmth, right?

[Anonymous No.1870566]

>>1870555
Mastering has already killed the dynamic range by compressing the sound. How are you going to unmaster it and remaster to your liking?

[Anonymous No.1870576]

>>1870555
Yeah, I can't stand accurate audio. I feel bad for the artists who recorded it. Perfect accuracy - must have been unbearable. I'm working on a system to intercept and record the sound that would reach my ears in day to day life, clip it like crazy, and play it back. After that I'm going to try to develop ordering a dildo from Amazon so I can fuck my own asshole instead of staying stupid shit on the internet

[Anonymous No.1870603]

>>1870532
I would advise to stay away from the cheap Chinese scopes, at least the USB ones and the DSO138s and similar. You’ll want 2 channels (if not 4), those single channel scopes are a joke. In general, cheap analog scopes are a fair bit better than cheap digital scopes.

As for the function generator, yes your phone can work fine, so long as you can find a good app for generating signals. But you’ll be limited in amplitude output and won’t have a trigger output or a modulation input or the other handy things you get in a dedicated machine. Some Chinese function generators probably have these features, and for the price you may consider it worth upgrading. Or have that as your first project, to make a function generator.

[Anonymous No.1870635]

I have this circuit in a device I own. It's extremely inefficient, so I'd like to improve it with some sort of switching voltage regulator. The only one I can get at a reasonabke price is the MC34063A, which has a maximum input voltage of 40V. Is there some way to make it work? Maybe using the existing linear voltage regulator to get down to the 40V the IC needs and then using that to get to 14.3V?
Also, what could I do on the negative side? The MC34063 takes a positive Voltage, so how could I deal with that?

[Anonymous No.1870637]

>>1870555
I'm clearly talking about noise introduced by equipment, not issues which are speculatively introduced. Nice strawman tho, but wasn't part of my argument. Funny how you have to introduce garbage noise into my argument for you to have a point.

[Anonymous No.1870672]

I want to make a robotic arm that points with a laser pointer to a input i.e. a constellation.

Does anyone know any libraries or apis for star locations?

[Anonymous No.1870686]

>>1870635
You either need a dedicated split-rail switching controller, or "complimentary" switching controller ICs (switching equivalent of 7805/7905). That or two identical isolated buck converters chained together, I suppose.

[Anonymous No.1870704]

>>1868933

Don't worry, there's ALWAYS one of these guys who go

>I never study and I know X, only stupid people have to study and learn X
>Look mom, I'm being an elitist on the internet!

Just tell them to fuck off, otherwise they will go "you HAD TO learn THAT too?" even if they don't know what they're talking about. It's a waste of time.

[Anonymous No.1870706]

I'm modifying a machine in work that uses a large modular PLC.
Basically I want the circuit I'm adding to switch on when a circuit that is already in the machine switches on so I was going to just tap off the same output on the PLC and use it to drive an SSR.
However I just want my circuit to be steady on as long as the other circuit is running but the PLC is using PWM to vary the power to the original circuit.
Is there a simple way to turn this 24V square wave into just a steady 24V, something like rectification?

[Anonymous No.1870707]

>>1870706
Diode + small cap should do the trick, with a discharge resistor too. If it's powering an SSR or MOSFET or anything with an insulated gate, you'll need that discharge resistor. Might want to add a transistor to it in case the cap and resistor pull too much current from the PWM wave.

[Anonymous No.1870708]

>>1870707
Like a transistor on the high side like pic?

[Anonymous No.1870710]

>>1870708
Forgot to draw discharge resistor in there

[Anonymous No.1870745]

>>1870708
>high side
Oh, because otherwise it would be inverted? Should work fine I guess.
With a discharge resistor across the capacitor too. Actually, the discharge resistor might cause the SSR to switch off really slowly and make some heat. Might need to schmitt trigger that with a comparator or logic IC or whatever.

[Anonymous No.1870746]

>>1870635
>It's extremely inefficient,

sure, because you're using +-43V to generate +-14V. that's insane. replace the transformer for something sane and your efficiency goes way up. you can stay analog and pure instead of inserting evil death-causing high-frequency noise into your life.

[Anonymous No.1870757]

>>1870635
Linear regulators work better with low voltage diferences between input and output. That's why lab supplies usually have a switching pre-regulator that keeps 2-3v above the output that is followed by the linear regulator.

[Anonymous No.1870800]

>>1870603
I've searched on the internet and I found three candidates for my first oscilloscope:
>Hantek DSO5072P
Cheapest of the bunch at 167€, 70MHz, widely shilled, can be hacked to 200MHz, but probes are good only up to 80MHz
>Hantek DSO5102P
The only difference with the 5072 is that this is 100MHz and probes are good up to 150MHz. Equally shilled as the smaller brother. Costs 10€ more.
>Hantek DSO4102C
Same specs as the 5102. Has an integrated arbitrary function generator, but the layout of the knobs and buttons is ass. 200€. Not nearly as shilled as the other two.

[Anonymous No.1870812]

>>1870757
still can't come to terms with the fact that lab supplies are supposed to be high accuracy low noise and yet they are based on switching regulators. insane. why do people care about efficiency so much.

[Anonymous No.1870822]

>>1870812
>why do people care about efficiency so much.
>energy = money
>wasted energy = heat you have to get rid off = fans, space and copper

[Anonymous No.1870826]

>>1870822
sure the industry is highly competitive so of course commercial designs compromise quality for the sake of saving nickels and dimes and. But for DYI? You are not saving anything anyway. The switching technology is an absolute and utter shit when it comes to noise. Just look at the scope. It is horrific. Linear all the way. Big trannys, lots of copper, huge sinks and fans. It is bulky but high quality.

[Anonymous No.1870827]

>>1870826
That is like saying
>veichles with wheels are terrible for moving around
There are switching regulators and switching regulators. If one model fits your noise requirements then I don't understand what you are talking about. And as I said, switching pre-regulators with linear outputs are a thing, so are low-noise switching converters.

[Anonymous No.1870828]

>>1870757
That's not true, the PSRR is higher with higher voltage drop

[Anonymous No.1870829]

>>1870828
I was talking about efficiency improvements, not ripple rejection. But you are correct.

[Anonymous No.1870830]

>>1870829
My bad.

Speaking of PSRR, I have a 1.2MHz 15V switcher-> 12V linear power supply on my headphone amp and I'm still getting at least 50mV of switcher noise on my output signal. It's inaudible but I'm confused about it. Maybe some sort of poorly laid out ground plane thing - still, it seems hard to believe. Came here to vent

[Anonymous No.1870865]

>>1870830
Ferrite bead at the linear input?

[Anonymous No.1870870]

>>1870865
Maybe the next revision. I've been relying on the LC filter and decoupling caps but it seems that might be insufficient

[Anonymous No.1870887]

>>1870812
Any power supply worth its salt has filtered the shit out of the output. With the move towards higher frequency switching (easier to filter) and with resonant switchers becoming more common power supply noise is becoming a thing of the past.

[Anonymous No.1870926]

>>1870887
>With the move towards higher frequency switching (easier to filter) and with resonant switchers

that just means the noise is radiated less thru the wires and more thru the air, fucking up every sensitive project within a 37.3-inch radius.

[Anonymous No.1870930]

>>1870926
What the fuck are you talking about. It's just that it makes the filter components smaller and cheaper.
>treating technical subjects as politics
This is what /pol/ did to us.

[Anonymous No.1870938]

>>1870830
>doesn't affect the device
>still complains
what

[Anonymous No.1870940]

>>1870926
>37.3 inch
That seems to be very specific

[Anonymous No.1870947]

>>1870746
I know why it is inefficient. The problem is that I can't change the transformer, since the ±43V is used elsewhere in the circuit. My first thought was doing something similar to what >>1870757 is saying: put a switching regulator in front of the linear circuit to bring the voltage down to around 16V. But that can't work.with the only switching regulator IC I can cheaply get, since that has a maximum input voltage of 40V?
Hence my question wheter it would be feasible to either run the MC34063 at 43V, or to use the existing regulator, but changing the zener so yhe output is <40V which I would then feed into the switching regulator, set to output my 14.3V.

[Anonymous No.1870959]

Does this mean 32 volts flutuating between 25 and 37?
Same with the 26

[Anonymous No.1870970]

>>1870947
>would be feasible to either run the MC34063 at 43V, or to use the existing regulator, but changing the zener so yhe output is <40V

both are feasible. a chip rated for 40V will handle 43V 99 times out of 100. however a 5V 10W zener in series will guarantee it works 100/100 times. but what about the negative? doesnt seem doable to make another isolated negative output unless the transformer is made from two separate windings, instead of a being center tapped. unless you get a diff chip that can create dual rails like the chip in >>1870870. it's $6 at digikey, so 6 times the other chip, but still not too bad.

[Anonymous No.1870976]

>>1870959
>32 volts flutuating between 25 and 37?

hell no, it's a range you can expect given that line voltages vary from place to place and also during the time of day.

[Anonymous No.1870990]

Yo this is fucked jbl flip 4, the micro usb got fucked so i tried to replace it completle with usb cable, but I have got a problem there are two cables.... Why does micro usb have two cables how do I make this work. Sorry I am retarded

[Anonymous No.1871001]

Can conventional PWM SMPS controller chips like the MC34063 or the TL494 be configured to do pulse frequency modulation (PFM) instead of PWM? Wanna make a ZCS SMPS on the cheap and I wanna know if it can be done with cheap readily available controller chips in DIP packages.

[Anonymous No.1871003]

>>1870970
>just use a 10W zener bro
That's a fucking horrible solution.

[Anonymous No.1871008]

>>1870959
Nah, AC is fluctuating anyway.
If you measure it with a multimeter you're measuring the RMS voltage.
You should get a pretty steady reading it just mightn't be 32 volts.
It could be anywhere from 27 to 37V but it should be steady

[Anonymous No.1871014]

>>1871008
>It could be anywhere from 27 to 37V but it should be steady
Great, thanks! I just changed my old multimeter for a new one and I'm still trying to figure things out...

[Anonymous No.1871024]

>>1870938
I don't want my 1kHz sine wave to be an inch thick on my scope. It makes me feel bad

[Anonymous No.1871033]

>>1870970
>5V 10W zener
3.6V zener should be enough. At 100mA, that's 360mW, so a standard 0.5W one should be fine.
That way I would lose 0.36W in the Zener and 0.13W in the transistor if I use the switching regulator to get 16V.
I don't know about the efficiency of the switching regulator, but it has to be better than the 2W of loss I get currently.
The loss on the negative side iis only 0.5W due to the low current, so it's not such a big problem.

>>1871003
Why?

[Anonymous No.1871040]

>>1870990
One 5V, one 0V, if I understand correctly. A power only cable, as opposed to a power+data cable that has 4 or 5 isolated conductors. Do you need to transfer data?

[Anonymous No.1871049]

>>1871024
>hurr what is HF Reject

[Anonymous No.1871062]

>>1871040
I dont need to transfere data only to make power. Is there name to a kable you would sugest i use? I am really lost in this stuff

[Anonymous No.1871227]

>>1871062
A two wire cable should be able to transfer power just fine. Google image search for “micro USB pinout”. I think V+ and GND were on opposite sides, tracing the circuit should tell you which is which just from context. Also note that you may need some form of strain relief after soldering two wires directly onto where the micro USB socket used to be. I don’t think you’ll need resistors across the data pins, which is the case for some USB power applications.

[Anonymous No.1871265]

>>1871227
Not the guy you're responding to but I have a rasp pi v4 that will end up getting hooked up to a 12V battery backup solution I'm custom designing. On board will be a switching converter which regulates that down to 5V for the rasp pi. That normally derives its power from USB-C. Can I just supply it with only the +5VDC and ground or do I need a smart charger with USB-PD capability in order to even supply current to it? If so can I power it via GPIO pins instead?

[Anonymous No.1871296]

I am reading and writing signals with bits that last 3us. The device Im connected to sends a signal about every 2ms and I absolutely cannot miss it so interrupts are disabled while I am reading and writing.
I also want to debounce a push button at the same time with interrupts. Timing is critical here as well just not as much. Im actually using a dualcore mcu right now so this wouldnt be too much of a problem but I want to make a circuit based on a different chip so I dont want to rely on that. This is also partly why I cant have a hardware solution to debounce.
Any suggestions, tips, pointers?

[Anonymous No.1871309]

>>1871296
What do you mean?
>timing is critical here as well just not as much

Is it not as critical to the point that it can wait until the read/write is over?

[Anonymous No.1871312]

>>1871265
Connect the buck converter directly to the GPIO pins. It should be able to supply 3A continuous minimum with the voltage set a little high (5.1-5.2V depending on wire gauge/length)

[Anonymous No.1871330]

Is this 3 phase?

[Anonymous No.1871336]

>>1871330

maybe. often you'll see 3 wires above which are around 12,000V three phase. then 2 of those phases go to the transformer, which puts out 240V split-phase (i.e. center tapped). that goes into your house.
if you have a factory and you need 3-phase power, they'll put up a special xformer that'll take 3-phase in and give 3-phase out.

[Anonymous No.1871339]

>>1871336
Well I don't NEED 3ph but I want it. Buying a house and the 3ph tools are better. Running 3ph is expensive as fuck apparently but those wires run by house so would be "cheap" to run it 100ft to the garage. Probably.

[Anonymous No.1871342]

>>1871339
The three phase would be the INPUT to the transformer, not the output from it. That means you're talking somewhere in the range of 4kV-30kV. Attempting to tap into those lines would not only be illegal it would be suicide.

[Anonymous No.1871349]

>>1871342
I didn't mean I was going to do it myself in the night but have the power company bring 3ph to my building. If possible.

[Anonymous No.1871361]

>>1871349
Oh, I see, I misread that.

[Anonymous No.1871371]

>>1871349

dunno about your jurisdiction, but around here if you have 3-phase installed for business purposes, then you can install your own transformer inside the house to convert that 3-phase to 240V split-phase to power the whole house. and you would do that because then your entire electrical bill, for both home and shop, become a business expense. so, if your tax rate is 30% on biz profits, you save 30% of your electrical bill.

[Anonymous No.1871407]

>>1871371
I'll have to ask a local elechicken.
How many years can I go without making a profit before the tax man come knocking? Microsoft still hasn't made a single penny in profit on Xbox.

[Anonymous No.1871412]

>>1871330
>blurry picture where you can't even count wires
ok

[Anonymous No.1871414]

>>1871412
Its Google maps, best I can do in the middle of the night.

[Anonymous No.1871422]

>>1871414
3ph transformers have 6 connectors (Atleast here in brazil). I believe some older instalations (and sparsely populated places) use single phase branches for group of houses/streets but most of them just use a 3ph and balance each phase so they have a similar load. You should contact you utility company, they are usually efficient and clear with this sort of information. (Max load for a plot of so and so sizes, location of HV lines, how much it costs for a 3ph or 1ph connection to diferent sorts of enterprises etc)
>electrician question
>/ohm/

>3ph tools better
?

[Anonymous No.1871433]

>>1871422
Yeah the 3 phase machines are built like tanks for industrial use unlike consumer grade 1 phase machines. At least for what tools I'm looking at.

[Anonymous No.1871440]

>>1871414
I'm on a standard 3~/400/N/PE 32A distribution like every home here. Sockets are 230V 50Hz 16A. 20kW water heater has direct 3ph connection.

[Anonymous No.1871461]

>>1871440
If that is the case then just contact the utility company and they'll tell what you need to do/pay.
If even in brazil they manage to get on time, install shit correctly I think for you in the first world it's gonna be ok.
>>1871433
YOu are putting the carts ahead of the animals my friend, if you want a good single phase tool then you can find one. The number of phases is related to the kind of motor used and their power and torque ratings and also simply due the fact that for some power ratings you need three phasic stuff unless you want wires ticker than your torso.

[Anonymous No.1871479]

>>1871461
Well they don't make a 1ph 16" joiner, I'd have to get a smaller 12" if I wanted a 1ph tool.

[Anonymous No.1871501]

>>1871414
I see 2 wires + CATV, so probably no
>>1871479
I worked a little while in a shop that had some 3 phase tools running on split phase using a rotary converter and some using a VFD. I believe the VFD gave a little more power. The guy who ran the shop said he had to get the power company to install a bigger transformer because the fuses on the pole kept blowing.

[Anonymous No.1871521]

I finished the pcb and now it's time to connect all the vias
Honestly though, It's great for smaller pcbs, but for bigger pcbs like this i think i will just bite the bullet next time and wait a couple of weeks for the chink fab house to make it. It just consumes too much time to do that shit by hand for a larger project.

[Anonymous No.1871622]

Anyone ever go to school for an electricians certificate? I would like to learn the trade, but dont know if the cost is worth it.

[Anonymous No.1871649]

>>1868373
I'm new to electronics. Should I go for a hakko or a chinese soldering station?

I've put together a list. Is this good?

[Anonymous No.1871650]

>>1871649
https://www.amazon.com/hz/wishlist/ls/23OPPHF42YI0Z?ref_=wl_share
whoops forgot the list

[Anonymous No.1871659]

>>1871649
This is /ohm/ approved cheap chink shit that's actually good for the money
>Quicko/Ksger T12 soldering station and a pack of T12 tips (and a base)
>Aneng AN8008 or AN8009
Also, get a set of ESD safe tweezers, they're cheap and useful.

[Anonymous No.1871675]

>>1871659
>2020
>people still waste time and money on ESD shit instead of just working barefooted
top kek

[Anonymous No.1871679]

I don't know anything about thyristors and I'm confused by this circuit.
1. Wouldn't the thyristor get triggered into conduction only during the positive half-wave of the AC line?
2. How exactly would the microcontroller know the exact moment (zero crossings) to trigger the thyristor to control the light bulb brightness?

[Anonymous No.1871694]

How are the books that are in the OP?

[Anonymous No.1871695]

>>1871679
>1. Wouldn't the thyristor get triggered into conduction only during the positive half-wave of the AC line?
Why you think so?
>magic box does thing
>How exactly would the microcontroller know the exact moment (zero crossings) to trigger the thyristor to control the light bulb brightness?
PR senses light. Probably the uC senses the 60hz flicker and works with that

[Anonymous No.1871707]

>>1871679
>How exactly would the microcontroller know the exact moment (zero crossings) to trigger the thyristor to control the light bulb brightness?

it doesnt know and doesnt care. zero-crossing detection is great for several reasons but i'd suggest 95% of triacs circuits in use dont implement it. also, it's way more likely that there's no brightness control, just on/off.

>>1871694
>How are the books that are in the OP?

they have received ohm's highest recommendation. i.e. they suck cocks. feel free to pirate-bay some better ones, which only you can recognize coz you are a unique leaner, like everyone else.

[Anonymous No.1871713]

>>1871679
>How exactly would the microcontroller know the exact moment (zero crossings) to trigger the thyristor to control the light bulb brightness?

it doesnt know and doesnt care. zero-crossing detection is great for several reasons but i'd suggest 95% of triacs circuits in use dont implement it. also, it's way more likely that there's no brightness control, just on/off. cnat tell without source code, for the (ahahahahah) Freescale 68908 micro.

>>1871694
>How are the books that are in the OP?

they have received ohm's highest recommendation. i.e. they suck cocks. feel free to pirate-bay some better ones, which only you can recognize coz you are a unique learner, like everyone else.

[Anonymous No.1871770]

>>1871521
How much force can those helping hands withstand? My ones are similar (probably cheaper) and they just deflect at the amount of force required to solder a joint.

>>1871679
That's a TRIAC, not an SCR. If you look at the circuit diagram of a TRIAC, you should see that it should be able to be triggered by a positive pulse regardless of whether there's +120V or -120V at its far leg. I think. As for the sensing, either it picks up the ripple from its input, or can sense the difference in load current through the TRIAC itself. But usually I'd expect to see a seperate input with a seperate (unfiltered) rectifier + zener as a zero-crossing input.

[Anonymous No.1871783]

Having some issues with quartz crystal design
Using it with STPM32, datasheet is not overly helpful and neither is reference design
So using 16MHz 8pF small oscillator managed to get it working by removing load capacitors and adding high value feedback resistor

Is there some cheap way to measure crystal pins?
Some cheap 100x probe I have seem to have too much capacitance, can still somewhat see crystal waveform but chip is not working
Or should I just fuck it and call it a day if everything is working with clkout giving good good output?

>>1871679
triac's trigger when current is flowing through gate and it doesn't matter when you trigger it, just voltage should be high enough if you want it to latch
Zero cross is unlikely to be included with schematic you posted, but brightness control is most likely done by measuring brightness with photoresistor and then adjusting on/off cycles via software, half-cycle is known so some basic logic and your'e good

[Anonymous No.1871794]

So I need dual rail outputs for my project and I figured why not do it all on one IC instead of separate. LTC3523 seems to fit except for one problem. I want to double check with someone more experienced.

Plan is use 4 primary alkaline cells : 3 in series one parallel for VCC = 4.5V. One output will be charging li-ion 5V, 500 mA. Now here's the problem: in LTC3523 datasheet it says Isw=600mA I guess it's switching current so 500 mA is safe is that right? The other output will be stepped down to 2V, 200mA. Anyways this is my first time doing something like this so I could be way off

[Anonymous No.1871800]

>>1871794
>Isw=600mA I guess it's switching current so 500 mA is safe is that right
This is a bit confusing. At first glance I'd assume Isw is maximum instantaneous switching current, which will be higher than the output current. The Current Limit section specifies 1000mA peak so I don't know Isw is referring to.

Putting that aside, from this graph it looks like this IC won't work.

[Anonymous No.1871807]

>>1871794
>>1871800
It's minimum guaranteed switching current which which might be useful to know for peak power consumption
But yes, this chip is not suited for your application especially with batteries powering the device becaue Iout vs Vin is terrible when running at almost max power

[Anonymous No.1871820]

>>1871807
>>1871800
thanks. Yeah I made it overcomplicated too. Since my input voltage is ~6V and outputs: 2V, 5V two step-down with cells in series should be better. The reason I want good regulator design is I'm limited to 4 alkaline cells to run a lot of shit for as long as possible. The 5V output will be the most taxed. Are switching controllers instead of regulators worth investigating or is it overcomplicating? Thinking there could be sleep functionality and optimizations that would make a difference

[Anonymous No.1871823]

>>1871820
That's overcomplicating it. The main difference is that the switch isn't in the IC with a controller. You don't need much power so there's no need to bring it outside

[Anonymous No.1871848]

>>1871823
Okay I'm going down to two single output regulators. LTC1707 looks good for both cases.
>Vin1 = 6V
>Vout1 = 5V @500mAh
>Vout2 = 2.5V @200mAh

I'll check it over again when I'm not tired before ordering things. Also I think LTC datasheets are easiest to read and TI the hardest

[Anonymous No.1871851]

Red pill me on resonant smps topologies, are they worth considering to use or build as a hobbyist? Are there any good yt channels doing in-depth dives into smps topologies?

[Anonymous No.1871861]

>>1871851
Yes, especially if you need a smps.
they are extremely easy.

https://www.analog.com/en/app-notes/an-140.html

[Anonymous No.1871867]

>>1871851
There are decent yt videos on the general common SMPS topologies. There is obviously loads of information available on non-isolated PWM topologies like buck and boost since they're fairly simple and easy to explain. The isolated PWM stuff is harder to find more detailed info on though forward, flyback, push-pull, half-bridge, and full bridge are probably explored a bit in some videos and are thoroughly covered in various bits of literature (Only DCM tends to be covered in detail, I find info on CCM designs is typically tacked on as a footnote and not explored in detail).
Resonant forward converters as well as resonant half/full bridge, and SCR based converters (all PFM) are very hard to find any info on. Give up on youtube, you won't find anything useful. Forget about books too, it's not usually covered in great detail. You're basically restricted to various application notes and papers you find online to glean any information out of. Most of it is very technical so if you're kind of new to electronics it'll be hard to decipher. Also if you actually build these circuits you need ways to be able to characterize things like your transformer's leakage inductance because it's actually an important design parameter in LLC converters. At the cheapest end you need a GOOD LCR meter to do it or better yet a vector impedance analyzer or VNA. Anyway, it gets complex fast. There's a bit more info on PFM based buck and boost circuits though since they're simpler and not that dissimilar to their PWM counterparts, the controller IC is very different internally but the external parts don't change much.

[Anonymous No.1872058]

>>1871770
>>1871713
There is a filament lamp and a photoresistor

[Anonymous No.1872069]

>>1871679
>>1872058
Technically it could figure out the zero-crossing from an internal high-pass filter on the LDR, since lighting will flicker slightly at 100/120Hz. Maybe with some digital rendition of a PLL. If it's just a general-purpose MCU then it couldn't do zero-crossing sensing through the power pin, not to mention the capacitive dropper shifting the phase of it. You pretty much require zero-crossing to use a TRIAC from what I've seen.

[Anonymous No.1872089]

>>1871770
>How much force can those helping hands withstand?
a lot i have to push down pretty hard to make them spin

[Anonymous No.1872090]

>>1872089
must be made of non cheese-grade steel then, mine are junky.

[Anonymous No.1872111]

>>1872069
>You pretty much require zero-crossing to use a TRIAC from what I've seen.

that's complete nonsense. 1 billion installed light dimmers say otherwise.

[Anonymous No.1872114]

>>1871770
>My ones are similar (probably cheaper) and they just deflect at the amount of force required to solder a joint.
Those helping hands are very cheap. "Powerfix" is a Lidl brand.

[Anonymous No.1872119]

>>1872111
I meant to include all phase-fired circuits with my statement, oops. So a better term for both electronically timed 0-crossing designs and RC delayed phase-fired designs would be "synchronous TRIAC circuits". Unless you know of a circuit that can use a TRIAC for dimming with an asynchronous driver (i.e. normal PWM)? I'm pretty sure normal PWM will give all sorts of issues, even if you avoid aliasing.

[Anonymous No.1872120]

anyone made a synth for percussion unstruments before? analog circuits that can sound like drums, snare drums, cymbals, that sort of thing. be nice to avoid prepackaged drum samples without having to invest in an actual drum set, plus it might give me a lot more freedom as to what my drums sound like.

[Anonymous No.1872126]

>>1872111
good luck using that with a led

[Anonymous No.1872128]

>>1872126
They were not deisgned for LEDs
>>1872120
I think there are/were analog drum machines. No idea of how they work.

[Anonymous No.1872137]

>>1872119
>phase-fired
Phase-triggered sounds more rational, nothing is burning here. Would you call a DIAC a fire diode?

[Anonymous No.1872138]

>>1872137
>Would you call a DIAC a fire diode?
Seems pretty rad

[Anonymous No.1872142]

>>1872128
I think he's referring to mains LED "bulbs" If they have an integrated SMPS, then a TRIAC dimmer will do nothing for most of the phase. If you turn the dimmer way down, you'd get some unpredictable behaviour like flickering or overheating or whatever as the line converter IC ceases to start up properly. A capacitive dropper LED will work with a dimmer to some extent, but not that well, might get nasty current spikes. A HV LED string on a full-bridge with a linear current regulator will work just fine, but even at full brightness it will be flickery without any filter caps, but adding those filter caps will make it fail to dim on a TRIAC dimmer for the first 90° of phase, and only work on the next half, but flickery.
I suspect the best ones have an SMPS that interprets the chopped-up waveform of a TRIAC dimmer and adjusts its output current accordingly, similarly to the PWM pin on a servo.

>>1872137
"fired" as a verb doesn't imply combustion or munitions any more than "trigger" does.

[Anonymous No.1872146]

>>1872142
I know, and I said that that typical kind of dimmer was not designed for LEDs. Is this pedantic posting hours?

[Anonymous No.1872151]

>>1872146
everybody uses led bulbs, therefore what you posted is completely useless

get with the times grandpa, it's not 1950s anymore

[Anonymous No.1872158]

>>1872146
>that typical kind of dimmer
I've heard that other types are better for LEDs, but which ones? I can't imagine that a trailing-edge dimmer is any better for anything other than RFI. Do they just use higher frequency PWM across both halves of the waveform, using MOSFETs or whatever?

[Anonymous No.1872177]

>>1872158
led dimmers use zero crossing detections and trigger a triac 100 times per second if the AC is running at 50Hz, the delay in triggering after each crossing determines the brightness. The led has to support this.

[Anonymous No.1872178]

>spend months acquiring tools, and knowledge
>no actual serving purpose other than useless gimmicks

I actually learnt this shit with some weird Jason Bourne fantasy that one day I’d require this knowledge.

[Anonymous No.1872210]

>>1872151
I didn't post any diagrams you retard. And the original guys here
>>1872111
and here
>>1871679
had the filament lamp symbol. Calibrate your eyes
>>1872158
There are several technologies, most power electronics slightly more complicated than a flyback are active research and design topics so the market is still changing. (You can see this with how kW-MW power electronic modules have no standard whatsoever).
Anyhow, the best LED dimmers are the ones that come with the lamp, usually they do this on the DC side of things by just limiting the current. The problem is you can't just buy one of those and install.

[Anonymous No.1872221]

Hello. I am aiming to connect an old monochrome CRT to my desktop and I have a couple of questions. It only takes composite input, and is designed for the BBC micro era computers. What kind of video signal is the monitor expecting, is it normal composite pal/ntsc or something specific to these monitors? If I buy a very old GPU with composite outputs, will these work together? Does anyone know what the horizontal frequency of these composite monitors is? I understand it won't be easy, but is it possible?

Alternatively, I'd thought about connecting it to either the composite output of my raspberry pi arduino, but this limits what I can display on it.

[Anonymous No.1872225]

>>1872221
*raspberry pi OR arduino

[Anonymous No.1872226]

How's library compatibility between branches of ESP?
I wanna run a ESP8266 library on an ESP32
https://github.com/antevir/OrviboS20_Arduino

[Anonymous No.1872252]

>>1872221
>is it normal composite pal/ntsc or something specific to these monitors?

unless it has a SCART connector, then it's just good old composite video.

>If I buy a very old GPU with composite outputs, will these work together?

yes. you can also get converters: HDMI-to-composite, VGA-to-composite, etc.

>the horizontal frequency of these composite monitors

15Khz for ancient models, and 30Khz for newer ones. high-end monitors will accept a wide range.

>to either the composite output of my raspberry pi arduino

arduino doesnt have any video outputs, but the Pi 1,2,3 work fine. dunno if they still have it on RasPi 4.

[Anonymous No.1872312]

>>1872252
Thanks for the answers. The company making the monitor closed in 1985, so would that make it a 15khz set do you think? There is a library for composite video from an arduino, you just have to wire it up yourself:
https://tronixstuff.com/2011/05/30/tutorial-video-output-from-your-arduino/

The RPI 4 also still has the composite out.

How low resolution do the HDMI>composite adaptors go?

[Anonymous No.1872315]

>>1872226
No, totally different internally.

[Anonymous No.1872379]

>>1868539
You can achieve the same with a smaller relay, turning on a car starter relay. Some mofo did that before, it works.

[Anonymous No.1872530]

>>1869399
might sound daft but look for lightbulbs inside the organ, i know that some organs used lightbulbs as a resistor to compress sound but I don't know if its in yours.

[Anonymous No.1872545]

im trying to build UPS for 1A usb device. is this correct approach? if yes then should i bother with mos driver ic for faster gate discharge?

[Anonymous No.1872550]

>>1872226
it is unoptimised arduino lib so most likely it ll work with minor changes

[Anonymous No.1872582]

>>1872178
make guitar pedals and sell them to post-rock artists for 10 times more than you bought the parts for
bonus points if you make a yt channel showing off the effects

>>1872210
>the best LED dimmers are the ones that come with the lamp, usually they do this on the DC side of things by just limiting the current
That's what I was thinking, no flicker that way. But doesn't it result in a slightly different hue compared to PWM? Something about the phosphors getting saturated at normal high-intensity operation. Might be talking out of my arse though. Be interesting to test.

>>1872545
If the +5V drops slowly (e.g. large capacitance or failing PSU), will that MOSFET enter the linear region and get hella hot? Also the PFET needs to be switched fully on even at the minimum battery voltage, and since the maximum battery voltage has to be less than 5V for the FET to reliably turn off, it's a 1S, and 3V on many a MOSFET is borderline and high resistance. Could arguably make it 2S if your charge circuit can handle it, and if the FET will still definitely be turned off at that non-zero Vgs.
Also I'd see about managing to use an NMOS transistor instead, because it gives you much better options for choosing a transistor, PMOSs are significantly less common.

[Anonymous No.1872770]

If my circuit will draw 9 watts, would a 12 watt power supply be safe enough or should I get an 18 watt

[Anonymous No.1872795]

>>1872770
rule of thumb is 2x, but 12 watts will probably be fine. It can depend, however. Some things draw a lot of power at start-up then settle into their operating load. What are you powering?

[Anonymous No.1872807]

Anyone have experience with custom usb I/O devices for Windows PC? Any resources to recommend?

[Anonymous No.1872810]

>>1872795
Just an led lamp. Nothing fancy. The 18 watt adapter is a dollar more anyway, but out of curiosity would the 18 watt brick not get as hot as a 12 watt or is that not how that works

[Anonymous No.1872814]

>order chinkshit solder station
>says in US
>expect it to drop ship and take 3 months to shot up
>was actually in the US
>shows up in like 5 days
>the one order I place in an entire year on amazon takes like 10 days to ship despite prime
>numirch still 4 weeks behind
It is a dark day when the chinese are now the leaders in shipping.
I bet if I order tips from china they'll get lost just to spite me for this one instance of good fortune.

[Anonymous No.1872819]

If I want to display an image on my oscilloscope, a raster image with scanlines and what will be easier than vector, right? With something like an LM1881. Though I don't think my scope has a Z-axis input (which I think is used to modulate the brightness of the trace), just an external trigger. Still, if I could combine the ramp of one axis with the amplified composite video signal, I could just draw a bunch of scanlines as normal for white, but draw them out of the display area for black. This would probably work fine for a black-and-white image or video signal, so long as the rising and falling edges of my video signal are steep enough. Converting to black-and-white should be easier than making a vector image, especially for a video signal.
If I inverted a lower amplitude video signal on every second scanline it might be possible to get a 50%-100% continuous brightness variation as the scanlines overlap or not, maybe. No clue how I'd invert the video signal like that though, all-pass filter + a MOSFET?

On that note, what would be the cheapest and most compact method of getting a downloaded (and preprocessed) video stored and constantly feeding into my scope? I don't know if portable media players have video outputs, so I'm leaning towards a cheap rpi/clone, with an HDMI-to-composite converter. Not sure if I could get audio and composite video directly out of that TRRS socket, since I'd want to put a speaker on it too.

[Anonymous No.1872825]

Need suggestions for a heap and nice soldering station, whats a decent Hakko clone i can get that uses legit Hakko tips? my other option is a TS100 but i would rather get somethibg with hot air.

[Anonymous No.1872829]

>>1868373
look at that pansy holding the hot neck of the soldering iron that doesnt even have a head equiped. bet that faggot went to devry.

that is not how you break a surface mount inductor. you have to want to remove it intact then push slightly to hard as you attempt to move it while the solder is still hot

[Anonymous No.1872832]

>>1868373
Why is that guy's head so small? He looks like a cartoon

[Anonymous No.1872833]

>>1872582
Sorry I meant general current control. PWM is just another one of those methods (albeit non--linear)

[Anonymous No.1872834]

>>1872829
>soldering iron that doesnt even have a head equiped
That's a hot air blower you retard.
No point in complaining about an image that people have mocked for years, it's just a poorly staged stock image. But by all means, complain about the open hard drive, the soldering station's display facing the camera not the worker, the display not even on, the smell of burning flesh, the lack of workholding or even any solder or flux or tweezers or IPA, the poor perspective and focus from the background making it obviously greenscreened, and the lack of toxic vapours we've all come to know and love.

[Anonymous No.1872835]

>>1872829
based retarded poster

[Anonymous No.1872838]

interesting article on simple analog drum machines
http://mickeydelp.com/blog/anatomy-of-a-drum-machine?
the circuit blocks it's made of are relatively simple too, mainly just simple vca and decaying sine oscillator circuits. plus a couple mcus, one for noise and one for midi and keypad controlling

[Anonymous No.1872866]

>>1872545
>>1872582
+5V ll be usb so no large capacitance and there are cheap pmos with 0.07 omh or less at -2.5vgs. Btw i can switch pmos around (pic) right ? it wont leek though body diode or charge battery when 5V is up. And if i would end up with nmos what should i use to control it in this setup? opamp/schmit?

[Anonymous No.1872871]

>>1872866
>no large capacitance
I think it's 10µF max or so? At least that's for devices, not power supplies. As a USB power brick (or computer or whatever) turns off, its internal capacitors will discharge through your load, their voltage decreasing as they do so, and it's quite possible that they have 100µF or even higher.
>0.07 omh or less at -2.5vgs
That's fine. I'm not only worried about specs but availability also, being someone who buys parts from alibay. If you're fine ordering from digikey or LCSC (or actually managed to find those specs on aliexpress) then no worries.

Also why do you need a MOSFET in the first place? Would two diodes alone not work fine, or am I missing something? Or do you just want to avoid the diode drop by using what's effectively an ideal diode circuit? Because the first circuit you posted doesn't do that.

[Anonymous No.1872874]

>>1872835
>>1872834
>falling for 3/10 trolls
boys, i am dissapoint

[Anonymous No.1872877]

>>1872874
>i was just pretending to be retarded

[Anonymous No.1872882]

>>1872871
i was trying to make it as efficient as possible at least battery side and yeah first image was kinda retarded. Guess i ll have to get some pmos and test how bad is it with 100uf as calculations and analong is not my strong side...

[Anonymous No.1872883]

>>1872819
Okay it looks like my scope has an "External Blanking Input" BNC on the back, which if I understand IS a z-axis input. Neat, I guess.
Looks like trying to make my own composite clock divider instead of buying an LM1881 or similar is a bad idea though.

>>1872882
just spice it, friend

[Anonymous No.1872888]

>>1872582
>make guitar pedals and sell them to post-rock artists for 10 times more than you bought the parts for
Is there actually money in this? I've wanted to do it since making a tremolo back in college but it seems like the market is flooded with fuzz pedals where the main distinguishing factor is the paint job. I don't think I could bring myself to invent enough audiophool wank to fill a product page.
>bonus points if you make a yt channel showing off the effects
I think my guitar skills would not help sell pedals.

[Anonymous No.1872890]

time to assemble this shit, i love it when a pcb comes together

i also decided to raise the temp of my iron from 300°C to 330°C for this because i like to live dangerously

i swear to god, if this shit doesn't work after all the work i put into it i'm going to take a shower with a running toaster

[Anonymous No.1872892]

>>1872888
I think a couple years after corona people will have more disposable income to waste with pedals, but I've managed to sell one once. The finishing is the most important for music fags, and also how much you can bullshit them.

[Anonymous No.1872899]

>>1872866
gate voltage is relative to the source pin, so I believe this will give you weird hysteresis if the boost input ever goes low.
>>1872882
>i was trying to make it as efficient as possible
Look up oring controllers, they are designed for this situation.

[Anonymous No.1872905]

>>1872890
You are the plated hole dude? Why not just drill the holes and make vias look a bit diferent from regular holes and solder clipped component legs inside them? I used to do that, worked quite well.

[Anonymous No.1872919]

>>1872899
>boost input ever goes low
wait isnt it always VBatt - bodyDiodeDrop? if battery ever goes lower than 3V it wont supply
enough current anyway.
>Oring controller
looks interesting but i feel like it is overengineering for 5V 1A and would rather avoid ordering obscure components

[Anonymous No.1872935]

>>1872905
i never attempted to plate the holes, it wold take nasty chemicals and shit and that is way too much work for an uncertain outcome, i just connect the vias with wires

[Anonymous No.1872952]

>>1872919
>wait isnt it always VBatt - bodyDiodeDrop?
Yeah you're right, I missed that. As long as the turn on voltage is less than (battery voltage - body diode drop) it should have positive feedback that turns the mosfet the rest of the way on. If the battery is >=3v you'll want a mosfet that turns on a good amount by ~2.3v so you'll have to choose carefully.

[Anonymous No.1872983]

What would be a good heat sink so I don't have to sit and wait as long for a soldering iron to cool down after I'm done using it? I was thinking just a few inches of sand in a cup.

[Anonymous No.1872993]

>>1872983
how fast you want it to cool down? damp sponge could work just dont try to 280 to 30C at once. as for sand i would rather not put solder iron tip into sand as you dont want sand in your solder joints. Also not sure if just me but it feels like that t12 tips cool down faster than regular heating one, on the other hand I just leave soldering iron on work table and dont bother so cant really tell.

[Anonymous No.1872996]

>>1872983
Heat pipe/coil attached to the cold side of a peltier module with an inline reciprocating pump to circulate coolant.

[Anonymous No.1873004]

>>1872983

asbestos underwear.

[Anonymous No.1873005]

Is there anything like the VK2828U7G5LF but with bluetooth?

[Anonymous No.1873009]

>>1872993
Cool to the touch in 5 minutes maybe. I heard rapid cooling via water reduces the life off the tips which makes sense, then again it's chinese and sand probably wouldn't help either. I just want to know it's cool by the time I'm done cleaning so I can leave without thinking something is on fire.

[Anonymous No.1873017]

>>1873009
just get or make soldering iron stand. Cooling with damp sponge wont damage if you dont go full retard and try to 280C - room temperature in 5s. however if you just leave it unpluged in about 1-2mins it ll drop bellow 200C and wont even be able to ignite paper so worst case you ll melt some plastic or synth fiber but no fire

[Anonymous No.1873030]

Just soldered this bad boy. I've always been afraid of soldering but I've finally got the hang of it! I know some of the joints might have a little too much or too little solder but I'm just glad I managed to do it.

[Anonymous No.1873032]

I want to mod my Kobo mini. Quick question:
https://blueflyvario.blogspot.com/2017/01/blueflyvariobluetoothusbv12-released.html
I want to buy this for it's bluetooth+gps capability. It comes with a a battery.
If I say upgrade the kobo mini battery to https://www.aliexpress.com/item/32791910883.html a 3000mah battery, will I still need to power the module?

[Anonymous No.1873034]

>>1873030
Looking good anon, is that an arduino uno or something?

[Anonymous No.1873039]

>>1873030
i bet that IC is factory soldered you lying sack of potatoes

[Anonymous No.1873050]

>>1873039
lqfp is not that hard to solder just flux

[Anonymous No.1873061]

>>1873050
No. The joints are too clean. You are clearly lying. Please just stop.

[Anonymous No.1873071]

>>1873061
not him. have you ever soldered smd? its not that hard with proper tools. BUT looking at throughhole most likely he only solder the pins

[Anonymous No.1873080]

>>1873032
I don't understand what these things have to do with each other. You are going to upgrade the kobo battery and then use the old kobo battery in the altimeter? Or you are going to plug the altimeter into the kobo? Or you are going to upgrade the kobo battery and then connect the altimeter to the kobo via bluetooth?

[Anonymous No.1873083]

>>1873071
>have you ever soldered smd
yes, i have visited this hell couple of times

[Anonymous No.1873085]

>>1873034
Thanks. It's a teensy LC. I'm trying to make a library for the MAX7219 to drive an LED matrix pic related.

>>1873039
If you look at the previous photo the top left pin has too much solder. If it were factory soldered why wouldn't the other pins be soldered as well? Look at any pre-soldered teensy and the other pins will be soldered. I'm flattered that you think I'm that good lol.

[Anonymous No.1873090]

>>1873083
you should get good iron, flux, fan, paste and revisit that hell. after couple boards you ll realise that even qfn soldering is better than throughole

[bb /b/oi No.1873095]

/b/ro here this is amazing.

Does anybody have any experience with LED issues in cars?
>93 Toyota pickup
>Aftermarket taillights
>Both have running light
>Right turn signal/brake won't work
>hear a click whenever the signal is active


Thinking it could be a resistors blown out but I'm electrically challenged and angry pixies scare me

[Anonymous No.1873109]

>>1873095
>resistors blown ou
uhmmm what? are you using portable suns as turn signals? string of 1W leds are not going to burn a resistor. It's probably a loose wire, happens all the time on cars.

[Anonymous No.1873111]

>>1873109
>>1873095
pretty sure he ment fuse but it cant be one as usually right and left brake lights are on the same one. its most likely lose or burned/cut wire. check connections if you dont see anyting obvious then get mulimeter and find car wiring diagram

[bb /b/oi No.1873113]

>>1873109
The issue started when I failed to realize how unsecure the battery was the ground wire was in the battery. So there was no ground for while and just getting it raw. I check the wires :c

[bb /b/oi No.1873116]

>>1873111
Fuses and wires are in good condition. Even bent the fuse pins a little for better contact.

[Anonymous No.1873120]

>>1873113
absence of connection to the negative pole will simply mean there will be no power. it is in no way damaging to anything.
it can be anything, it's either bad wire, burned leds, or a dead chip somewhere on the car's motherboard, and they will charge you outta ass to fix that one

[Anonymous No.1873122]

> how unsecure the battery was the ground wire was in the battery. So there was no ground for while
if there is no closed loop between + and gnd current wont flow or do you mean that it was connecting on and off

[Anonymous No.1873123]

>>1873120
additionaly, get a multimeter, turn the lights on and start going down the chain, starting at the battery, then fuse box etc to find out where the juice stops flowing. make sure the multimeter is in voltage mode or you will be very sad

[bb /b/oi No.1873127]

>>1873122
The ground wire Literally ripped off. And I didn't notice bc life. So the car would literally die and not turn on at a stop or if I stalled out. (it needed a lot of work in the early days of ownership)

Also to everyone else the information is incredible I really do appreciate it.

[bb /b/oi No.1873133]

>>1873123
Noted and gonna have to just grow up and do it. Thank you for your help. With this gents. So what's the best plan of action. An Anon said to start at the battery. I'll look up a wiring diagram and see I can make sense. This thing has had a lot of hobbyists adding little accessories here and there so the wiring is a cluster fuck.

[Anonymous No.1873136]

>>1873133
the first thing you want to check with the multimeter is the connection at the lights, if there is power there it means the leds are dead, or have bad solder joint

[Anonymous No.1873138]

>>1873133
start from car to LED wires and make sure that GND WIRE IS CONNECTED TO GND (car chassis is usually ground) and that you actually get 0 at positive WHEN IT SHOULD BE ON

[Anonymous No.1873166]

>>1873080
the bluflyvario comes with a battery. I have a default battery in the kobo. I want to buy a new 30000mah battery for the kobo.
Essentially, does the bluflyvario have to have its separate battery or can I power the blurflyvario with the new 30000mah battery that I'm buying

[Anonymous No.1873169]

>>1873166
if both of them require same voltage battery then most likely yes

[Anonymous No.1873171]

>>1873169
thanks for answering. I asked an 'or' question, which thing were you referring to? I'm guessing the latter.

[bb /b/oi No.1873195]

>>1873138
>>1873136

Based Anons. Thank you for the tips. Will probably come back and newfag on this board.

[Anonymous No.1873211]

>>1873085
>top left pin
He said the IC, the QFN48 teensy, not the 0.1" pin headers.

[Anonymous No.1873216]

>>1873211
Oh shit I'm an idiot.

[Anonymous No.1873219]

I have an air blower for a wood stove that blows too damn fast.

I see a lot of conflicting information online about whether just putting a resistor in series will slow it down, or if a triac dimmer switch would work. My understanding is that the best or only way to do it would be to adjust the frequency.

Do they make small knob sized variac type devices to do this? Would a diode not half rectify the AC and give me half the RPMs?

[Anonymous No.1873254]

>>1873219
>I see a lot of conflicting information online

that's coz there's a greater number of motor types than there are genders, and they all need to be treated differently. most likely you have an AC induction motor, coz those are the type that are very quiet. if so, they're fixed speed. if you put a resistor, nothing happens. if you put a dimmer, it MAY work, but in an odd way. i.e. you'll get some speed control but not continuously variable speed. changing frequency will work, but VFDs are not exactly common or cheap. best thing to do is to live with it.

[Anonymous No.1873333]

i got a pi zero and a knock off arduino. the pi zero only has micro usb slots. the arduino just has a usb b slot. I connected the tx and rx lines to the arduino but do i need to power it too? can i do that with the pi gpio? how

[Anonymous No.1873349]

>>1873333

if you wanna power them together, just run 2 jumpers, from +5 to +5 and GND to GND on the expansion connectors. you can power either one, and the other one gets power too. however, you'd have to be careful with the power jack on the arduino to not overload the 5V regulator. the Pi can take about an amp, so that may be too much for the arduino regulator. going the other way should be okay as long as you apply power to the Raspi at the 5V IO pin, and not at the micro USB, coz the USB power input is fused, and you may blow the fuse.

[Anonymous No.1873353]

>>1873349
hmm yeah i read that connecting the 5v requires a logic gate. i'm new to the stuff and don't have one and i'm lazy and impatient.
i'll try powering the arduino first, i have it working the other way around right now

[Anonymous No.1873373]

In need of a soldering station, will be working on audio equipment (pedals, amps, etc). Want something made in the USA, willing to pay extra. Is something like this Pace a good choice?

[Anonymous No.1873414]

>>1873373
also looking for a multimeter, but it seems like unless I buy a $400 Fluke I can't get something American. Not sure what to buy as I'm really new to electronics, I'm trying to look up what resolution I'll need.

[Anonymous No.1873493]

>>1873414
Get a bench multimeter instead of a handheld. You can get used Fluke and Agilent bench DMMs for cheaper than a new Fluke handheld meter and they will generally be much better meters, especially if you're doing lower current/small signal stuff.

[Anonymous No.1873512]

Pulse waves are cool. A pulse with a duty cycle of 1/3 creates a node at the third harmonic, and every 3rd harmonic after that. A pulse with a duty cycle of 1/5 creates a node at the fifth harmonic, and every 5th harmonic after that.
Strictly speaking, a square wave just creates a node at the second harmonic, and every 2nd harmonic after that.

Is there any way to apply this to filters, or phasors, or flangers or anything else like that?
Pic rel is a 10% duty cycle

[Anonymous No.1873523]

>>1873512
That's interesting. I don't think you could meaningfully apply those harmonics with a filter, though I'd try filtering out groups of those harmonics just to see what you get. Might be able to do some interesting stuff with additive synthesis though.

[Anonymous No.1873527]

>>1873523
I was thinking you could use it as a multiplier for an arbitrary signal, like an active notch filter of some sort, but I have no idea where to start in practice

[Anonymous No.1873528]

>>1868407
Oh hey don't worry he was talking about some other zipper head

[Anonymous No.1873532]

>>1873527
For a VCF? I think its low-frequency harmonics would make much more of an impact than its higher frequency harmonics. But what I would try doing is running a variable-duty-cycle VCO as part of a PLL, filter off the lower-order harmonics, and add them to the PLL's source waveform. Might need a VCF for that too though, to keep the corner freq in the right place. Trying to replicate the same thing with triangle/sawtooth waves of different skew would reduce the need for a HPF.
PLLs are cool.

[Anonymous No.1873604]

>>1873527
You can use switching as a way of mixing signals together, there are also some PWM volume adjusters for sound applications. They are good for sound shit because you don't need to filter out the varying high frequency

[Anonymous No.1873639]

>>1873373
The one you posted is the first I've heard of an iron made in USA. Seeing as we don't make anything here we also tend not to make the tools for making things.
Watch out for the tips, they seem to be following the razor blade model.

[Anonymous No.1873643]

>>1873639
I don't understand this tip meme. My chinkshit tips have lasted me ages with no problems and I treat them like shit.
What does a bad tip even do? bead and drip solder?

[Anonymous No.1873648]

>>1873643
doesn't get covered in solder properly then it makes very annoying to try to solder things.

[Anonymous No.1873649]

>>1873643
Yeah, I've been using the same tip for years but I think it varies across different tips. Thinner coating means better heat transfer but they also wear out quicker, so the "high quality" tips may actually wear out faster.
I had one tip that basically got shorter until there was nothing left. Once you get a hole in the coating, the inside stuff (copper?) just dissolves or burns off pretty quickly. The solder also doesn't wet properly because it corrodes instantly.

[Anonymous No.1873763]

>>1873219
Most smaller fan motors are squirrel cage types and like >>1873254 mentioned a dimmer may work but you increase the likelyhood of burning it up and the torque become unpredictable. The only way to control these properly is with a VFD as induction motors are frequency dependent, not voltage, and a dimmer makes it worse as it controls the time the load recieves power instead of the amount.

[Anonymous No.1873767]

>>1873763
>>1873219
A resistor would help. Might have problems starting the motor so you'd have to see the power rating, motor type and operating conditions.

[Anonymous No.1873775]

>>1873767
For a universal motor, yes it would, but so would a dimmer in that case. A resistor is not the correct solution in this application, induction motors are a different animal altogether and using a resistor could cause failure, not to mention who knows how many VA the motor is.

[Anonymous No.1873802]

>>1873767
>resistor would help
or a light bulb in series

[Anonymous No.1873856]

>>1873333
i also can't upload code to the arduino only when I plug in the pi zero to the tx/rx connections. i have pi's tx going to arduino's rx and pi's rx going to arduino's tx, i think that's right. but i'm reading that you need a logic gate for those connections? can anyone explain?
this is my first time trying to make a project without instructions

[Anonymous No.1873867]

>>1873856

are the grounds connected together? coz you need a common reference point to make the rx/tx signals real.

[Anonymous No.1873868]

>>1873867
nope, i just have the ground next to the power plugged in near the 5v pin, i'll give it a try

[Anonymous No.1873872]

>>1873775
Resistors are (were) used to control induction motors. As I said, it's not an ideal solution. They work best with 3ph machines so probably will cause problems with a 1ph machines
>how many va
Yes, that's why I said he'd have to check the power rating and motor class.
>>1873802
Also, but again. Depends on the rating.

[Anonymous No.1873881]

>>1873872
They are mostly used during start-up positions to allow higher torques and mostly with wound rotors. Anyhow, anon has the motor with him, he can play as he want as long as he keeps aware of the heat and magical smoke and until we have more information we can all talk out of our asses about who read more on the subject.

[Anonymous No.1873892]

Considering building usb hub just because, found some microchip eval board that almost looks ideal
But UPD350 is not power management IC which is kind of problematic
So I assume PM-PD is essentialy buck converter with variable feedback controlled by UPD350?
Is bidirectional buck-boost worth trying to do?

>>1873353
>>1873856
Depends on what arduino board you have and what exactly are you trying to do
If you are trying to program arduino board via raspberry pi, you need to connect reset pin as well since chip programming via tx/rx is done by arduino bootloader

Another point - what board you have. If it's uno r3 where chip is powered by 5V, then you need logic level shifter since arduino has atmega328, in datasheet minimum input voltage is 0.9*VCC (for 5V this means 4.5V), while raspberry pi has 3.3V supply so well below minimum required for uno r3 so most likely signal is going to be undefined
Also I'm not sure if raspberry pi gpios are 5v tolerant or not, another thing you should consider

[Anonymous No.1873901]

>>1873892
i'm powering the pi via the arduino as the other helpful anon suggested
i've been trying an official arduino uno and also an inland uno r3. i bought them both around the same time and they look identical so i assume the arduino is r3 too.
i'll try the reset pin too. the ground didn't do anything. where does reset go to on the pi gpio?

[Anonymous No.1873922]

>>1873901
do not connect pi zero to uno, uno operates at 5V and pi zero at 3.3V (for gpios)
Like I said - I'm not sure if pi zero has 5V tolerant gpios (some clamping diodes will be present but not sure how much they can withstand)
At least add some resistor, 2k at least, in series between pins so current is limited in worst case.

Also my mistake - logic high is 0.6*VCC for uno boards, so this would be 3V minimum, so arduino at least should detect data coming from raspberry pi, but I'm not sure if it will be visible on serial monitor

But still, for programming arduino via pi zero you need to be able to reset chip, there is reset pin on uno header.
For more information you'll need to google, there are many examples of OTA (different hosts, like pi, esp32 etc) updates for arduino via tx/rx, some should go in depth on operation and implementation

[Anonymous No.1873931]

>>1873922
>uno operates at 5V and pi zero at 3.3V (for gpios)
can't i just use the 3.3 v pin from the arduino to pi then?

[Anonymous No.1873964]

>>1873881
I come here for the bants, most places don't allow for silly pissing contests.

[Anonymous No.1873976]

>>1873219
>>1873763
Capacitive dropper? Can't see it being any worse than a resistor at least, and it wouldn't overheat. You'd need a big capacitor though so it probably isn't worth it.

>>1873775
>using a resistor could cause failure
I take it you mean the starter/run winding / shaded poles not being sufficient for starting the motor due to the lower current? It wouldn't burn the motor up for at least a few seconds, which is more than enough time to do a test run and see if it works with your finger on the off-switch.

>>1873856
Wasn't there something about a logic level shifter being needed? If rpis are 3.3V that is, can't remember if they are.

>>1873892
A 328p can run on 3.3V just fine, but I think it requires setting the fuses to run the oscillator slower.

>>1873901
There's no such thing as an arduino r3, they're made and designed by different companies, there's no design continuity between them whatsoever.

>>1873931
rpis have a 3.3V regulator just as an arduino has one, so rpis can run just fine on 5V fed to the right pin. But you need a logic level shifter, not just to change the power rail.

[Anonymous No.1873980]

>>1873976
>There's no such thing as an arduino r3, they're made and designed by different companies, there's no design continuity between them whatsoever.
>>1873976
>there's no design continuity between them whatsoever.
now you're just being a prick

[Anonymous No.1873986]

>>1873931
>can't i just use the 3.3 v pin from the arduino to pi then?

no. both Arduino and Raspi operate at 5V. that's the power, not the actual IO pins. and both have 3.3V regulators to power some things locally. so, you can power one from the other, but it wouldnt do to connect together the 3.3V power pins coz they'll conflict being at somewhat diff voltages.

the other thing is the voltage on the IO pins. Arduino uses 5V logic inputs and outputs, whereas Raspi uses 3.3V logic. that's where you will need a conversion chip (or resistors and zeners, or transistors) to convert levels going both ways.

[Anonymous No.1873996]

>>1873976
His motor but I wouldn't risk it and have burnt out motors trying to do what he is albeit for a completely different application. The cheap and greasiest way I could think of is use a cheap class D amplifier and use the input with a siggen app on a phone to control the frequency. Assuming it's single phase.
>here I go pissing into the wind again

[Anonymous No.1874012]

>>1873996
Sounds like a good candidate for a 555.

[Anonymous No.1874054]

What's the best solder sucker tool design? I really don't trust the spring loaded 3$ ones.

[Anonymous No.1874057]

>>1871330
tree phase

[Anonymous No.1874058]

>>1874012
True, I keep forgetting about that. Plus MOSFETs are cheap and easy to come by in the power required.

[Anonymous No.1874066]

>>1868673
either wheelchair or a very cheap waiting room chair

[Anonymous No.1874166]

>>1874054
The spring loaded ones of quality like soldapullt work fine. Used for years fixing aircraft and still do at home.

[Anonymous No.1874187]

Someone critique my thermocouple-to-digital circuit?
This feels like overkill just to read a TC but all the prepackaged ICs on digikey are expensive or have crazy tolerances or use some crazy bus format.

[Anonymous No.1874197]

>>1874187
Bad resistor symbols.

What's wrong with MCP96RL01T-E/MX ?

[Anonymous No.1874199]

>>1874197
The RL's are +/- 4*C. I'm hoping to use this for some homebrewing, so I care mostly about decent resolution in the 0-100C range.
I could probably use the 9600 set of the same chip, but the I-type only goes up to 85C and the E-type is $6.76, at which point might as well see if I can build the damn thing myself

[Anonymous No.1874217]

>>1868373
whats the lazyology way of getting sound/voice to play with a little micro. obviously i could get get some external flash and a dac and do it that way. but im lazy is there some slave IC that i can flash music/voice recordings then tell it to play over its dac things with i2c or some shit.

[Anonymous No.1874229]

>>1873996
>cheap diy square wave vfd
Interesting thinking, but it will need to be on mains voltage, with nice big filter caps. Or just say screw it and don't filter the input at all. Or just PWM it, did we rule out PWM for some reason or another? PWM at f>>60Hz, that is, none of that phase-fired synchronous dimming nonsense.

[Anonymous No.1874231]

>>1874217
There are some pretty cheap memory ICs out there, but I'm not sure if a few kb on an EEPROM would be enough. To get the audio back out of it, just have the MCU to read each value and PWM it at a sufficiently high frequency, then throw that through a low-pass filter. Basically a class-d amp without feedback. But 10kHz probably won't be fast enough, and I'm not sure if MCU PWM goes much above that, so you may need to hand-write a PWM code. Add some DSP to it too, if you want.

R2R ladders are also relatively easy, and you wouldn't even need an MCU here, just a clock and a counter feeding the EEPROM's address pins.

[Anonymous No.1874247]

>>1874231
yeah im just going to get some flash and the onboard dac on the micro im using. easiest way to do it

[Anonymous No.1874281]

>>1874247
>onboard dac
Well fuck, shoulda mentioned that in the beginning. What micro?

[Anonymous No.1874312]

>>1874187
How do you do cold junction compensation?

[Anonymous No.1874315]

>>1874281
i am looking at using the PIC24F08KM202

[Anonymous No.1874317]

>>1874312
If he's reading that analog value with an MCU, he can just connect another temp-sensor near the cold-junction and add his thermocouple ∆T to that.

[Anonymous No.1874318]

>>1874312
>>1874317
The tmp236 is the on-chip sensor.
On that diagram, the TC signal out of the inamp is labeled "tth" and the sensor's signal is labeled "tsn".
They get added together by that resistor bridge on the + end of the output opamp, which shifts the signal to the output range of 0V at 0C, 5V at 120C.

There won't be an MCU on this board, all of my peripherals are going on a big I2c bus over cat5 cable that runs to a raspberry pi.

[Anonymous No.1874320]

>>1874318
Oh neat, though I hope you're using some trimpots in order to get it calibrated. What's an MCP3021 like? Looks like a convenient IC, though I wonder what kind of current it can source in the case that you've got a few metres of cat5.

[Anonymous No.1874329]

>>1874320
I'm not sure yet. It's one of the cheapest ADCs on digikey but I couldn't find anything egregious on the datasheet. I'm half expecting to have the thing show up and be utterly broken because of some weird characteristic that I didn't think to check.
I'll probably order an assembly of these parts tomorrow so I can breadboard the whole thing to verify.
Good call on checking the bus limits. Apparently the MCP3021 is good up to 400 pF, and wikipedia lists cat5 as around 50 pF / meter. 8 meters will probably be plenty, and the 400pF limit was specified at 400kHz which I definitely do not need. Hopefully slowing it down a bit will relax that requirement.

[Anonymous No.1874338]

I'm brainstorming an additive synthesiser that uses triangle waves and PLLs, here's what I've got so far. So the idea is that I have a master triangle wave, which goes into a series of these voltage-controlled phase shifter circuits (pic related) that produce a square wave with a phase offset compared to the original triangle wave. Though this phase offset only goes from -90 to +90 degrees (ever so slightly less, for stability), I can add a switch to invert the output to get the full 360 degrees. Each phase shifter will be controlled with a potentiometer and the aforementioned flipping switch, before being fed into a frequency divider, and then the phase comparator of a (triangle wave) PLL. Then I have an amplitude potentiometer on the output of each of those PLLs' VCOs, before summing all the harmonics together. So I'd be able to add a bunch of triangle waves (say, 8) together, with the ability to alter the phase and amplitude of each one, but such that this phase and amplitude shouldn't change with fundamental frequency. Just gonna use an XOR gate for each phase comparator, and probably NOR gates for my SR latches.
Still don't have a VCO design though, probably just gonna do what I've got here (1 comparator schmitt trigger, 1 op-amp integrator) with a vactrol on the integrator. Any other design I can think of doesn't have a constant output amplitude.
I also can't think of a way to use uber-cheap dip-switches to do the inverting (or just swapping to notQ), my thoughts keep leading me back to SPDTs, which aren't that bad I guess.

Thoughts?

[Anonymous No.1874340]

>>1873373
>station
No.
Get ts100

[Anonymous No.1874343]

>>1874338
Here's the waves. Naturally, the inverted reference voltage goes from +4V, down to -4, then back to 4 again. You can see the limitations I have with the maximum and minimum phase shifts; if either reference voltage gets above/below the triangle wave, it will lose lock and no longer produce a square wave at the right frequency or even a wave at all. I think ideally I'd have a very thin spike at the top of each of my triangle's peaks (and at the troughs), so I can never have that issue. Like an extra 20% of the amplitude on the top and bottom. Anyone know how to do this, without nonlinear shit like an exponential amp or anything else that also depends on voltage thresholds? Filters likely won't work either, because it's a variable frequency oscillator, but they might.
Also no it won't be polyphonic, that would require duplicating the entire circuit.

>>1874340
TS100 shills out again I see, imagine shilling the TS100 when the updated TS80 is here.

[Anonymous No.1874344]

>>1874343
>TS80
ts80 is inferior to ts100 in several important ways and way more expensive to boot
do NOT buy ts80, get ts100 instead

[Anonymous No.1874345]

>>1874344
It's also superior in several important ways. Ways which I will not elaborate in this post because I'm a paid shill who knows nothing about the actual nuances of either product.

[Anonymous No.1874348]

>>1874345
They hates Jesus because he spoke the truth.

Go ahead and buy your crappy ts80 then kid. It's your own money and you can throw it away if you want.

[Anonymous No.1874357]

>>1874338
>>1874343
I was also wondering whether, with those two comparators leading into an SR latch, I'd be able to use a 555 or similar. Since i need to feed a seperate reference voltage into each comparator, and have the other lead of each comparator tied together and to my triangle wave, I don't think it's possible with a 555. Maybe there are some timer ICs with more versatile pinouts.

I'm trying out filtering the triangle wave in spice to just get the sharp peaks so I can add them to the waveform, but my high-pass filters are acting like low-pass filters, triangle waves are weird. Plus the phase is off by 180°.
Maybe a peak-detector circuit is what I need instead, I'll look into those.

Also it might actually be necessary that the phases are shifted AFTER the frequency multiplication, but I think I can do that without incurring unpredictable phase shifts from the state of the counters, probably.

[Anonymous No.1874369]

Shoudn't the voltage and current on a AC power source attached to a resistor have a 180 angle offset? (So v(t)*i(t)<0)

[Anonymous No.1874383]

>>1874369
Yes I think so, so the power source produces power and the resistor consumes it.

[Anonymous No.1874415]

>>1874369

silly question. there's nothing in the makeup of a resistor to cause a phase shift. voltage and current are 100% in phase.

[Anonymous No.1874421]

>>1868373
Is there any way to check if a device has a WiFi module in it? Besides opening it up and looking closely at the circuitry. Are there any kind of detectors?

[Anonymous No.1874424]

>>1874415
Yes, the angle is zero. Both power and energy are scalars. If you want the direction of energy flow you need an additional spatial reference to get a vector, e.g. that of the power density. When you reverse the polarity, the direction of flow is not affected because E x H remains the same.

[Anonymous No.1874426]

>>1874421
>are there any kind of detectors
Yes. Now if you want help just give us device name

[Anonymous No.1874459]

>>1874415
Low IQ post.

[Anonymous No.1874474]

>>1874426
It's a noname chinese kvm switch. I'm kind of afraid of passing all my keystrokes through it, hence the question.

[Anonymous No.1874477]

>>1874474
The tool you require is called a frequency counter or EMF meter. Wifi signals fall between 2.4 & 5 GHz.

[Anonymous No.1874485]

>>1874474
You can put it in a metal box.

[Anonymous No.1874487]

>>1874477
Do you think it will detect searching for WiFi APs? I'm trying to detect the "receiver" not the access point.

>>1874485
Yes, that was my initial plan, but I read that the box shouldn't have holes that are larger than 3mm so the holes for the wires might ruin it.

Anyways, I'll just try to setup a public WiFi next to the KVM and look at the logs.

[Anonymous No.1874489]

>>1874487
Uh not really. If you put in a metal box with holes the signal will be attenuated a lot. If you put in a perfect box then no signal will come out.

[Anonymous No.1874490]

>>1874487
The wireless module is a transceiver as well as the AP/router, and it operates on the same frequency. Yes, you will be able to detect a wifi signal from either end, but you need a noise signature and DSP to differentiate from other devices signals, or a Faraday cage to isolate the suspect device. You want a logging/graphing feature on the frequency counter so you can detect signals over time.

[Anonymous No.1874522]

I suspect a broken one of these is making my equipment glitch out since I'm reading 2 volts less than the spec sheet.
This outputs AC, can I use my labs power supply that outputs DC to test the board that feeds off the AC transformer?
If not how can I determine the fault without buying a replacement transformer?

[Anonymous No.1874527]

>>1874522
Is the transformer output rectified in the original circuit? Post spec sheet.

[Anonymous No.1874532]

>>1874522
yeah, the transformer probably feels into fool bridge rectifier anyway

[Anonymous No.1874550]

>>1874474
> I'm kind of afraid of passing all my keystrokes through it
>literally connects to fucking PCs
>worried about wifi modules inside

[Anonymous No.1874560]

>>1874527
>>1874532
It's an electric organ, using the bench PSU gave me power but no sound, I'm guessing maybe the amp part wasnt rectified?
I'm assuming the low voltages cause glitches like weird notes sounding when no input.

[Anonymous No.1874564]

>>1874522
Uh sure dude just clip the wires or something.
>>1874560
The picture shows that most stuff is rectified, but you clipped the part where it shows the amplifier. But it is most likely also rectified.
Uh remember that guy who asked about how inverters send power to the grid? Well I actually put my noggings to work and read some books. It's related to the phase diference (Voltage phase diference!) between the grid and the internal voltage at the inverter. Pic is a basic proof. Apparently it is a babbys first intro to power grid dynamics and works for any AC source.

[Anonymous No.1874567]

>>1874564
>>1874560
Also if you suspect the transformer is broken (it almost never is) just disconnect it from the device, and measure the secondary voltages while connected to the wall. You won't get shocked if you only play with the secondary coil.
>>1874564
To clarify, in sync machines the theta used here is called "power angle" (not power factor!). It is both the internal voltage phase diference and the angle of the rotor with the resultant magnetic field. Cool. I'm just happy that my brain hasn't atrophied during covid, I'll stop blog posting now

[Anonymous No.1874576]

>>1874560
>>1874564
>>1874567
I'm suspecing amp wasn't rectified since it worked fine but no sound.
Anyway, discoveries were made, my multimeter is whack and measures 1-2v off all mesurements. I borrowed one and made sure.
Spec sheet mentions CN11 pin1-2 = 26±4Vac but I'm getting straight 5Vdc, so that can't be right.
What on earth is a VOK Generator, I'm not finding any info online

[Anonymous No.1874581]

>>1874576
dude basic troubleshooting here. You said you suspect the problem is the transformer right? Measure the transformer. It says there they should be 16v and 13v. (so if you measure red to red you'll get 32v). And the amplifier IS rectified,

[Anonymous No.1874584]

>>1874581
Yeah, sorry I maybe wasn't clear, been there done that, I suspected the transformer because my multimeter was reading off, now I have a new one I can accuratly say the transformer is in spec.
I've been troubleshooting following the spec sheet and the only point I can find that doesn't light up is the pins I mention that are supposed to carry 26Vac but carry 5Vdc (as far as I can tell), so whatever the VOK generator is it doesn't seem like it's working.

[Anonymous No.1874588]

>>1874584
Unless you can spot something obvious you should follow the trail then.
>wall->transformer->diode rectifiers->regulators->other shit
The diode rectfier is the big diagonal stuff with an arrow. The regulators are IC2,4 and 6. I'll repeat, what you are showing is NOT an amplifier output. It's just a bunch of regulators and some other shit.

[Anonymous No.1874601]

>>1874576
The presence of the VOK signal tells you that the voltage is ok, hence the name.

[Anonymous No.1874607]

>>1874601
>VOK signal
Mind blown

>>1874588
Yeah, I'm aware, I wasn't trying to troubleshoot the amp, it's working.
I'm trying to work my way backwards from the CPU & Sound generator board, the one mentioned next to the CN11 connector.
Following instructions from the troubleshooting section of the Service Manual I've spotted that the VOK output on CN11 and GND should read 26Vac but I'm getting 5Vdc so I'm suspecting the BC550's are toast.
Does this more or less make sense or am I barking up the wrong tree?

I suspect I may be wrong since it strikes me as weird the device would power on and work with the ocasional glitch with a reading so off.

[Anonymous No.1874652]

>>1874424
>Both power and energy are scalars
Scalars can be negative as well as positive, I'd say treating that as a 180° phase difference is at least a tiny bit sensible.

You can also express power in the complex plane, just as is done in order to measure/calculate power factor of an arbitrary phase difference. Though perhaps this complex power should be treated as more distinct a concept.

>>1874576
>fuse after the Y caps
probably not a big deal but ok
>transformer across live and ground not live and neutral
WhaAT thE FuCk

[Anonymous No.1874697]

>>1874607
>should read 26Vac but I'm getting 5Vdc so I'm suspecting the BC550's are toast

either the manual is wrong, or you're confused. if you trace the VOK signal back, it comes from a transistor that's powered between 5V and ground. so, that transistor can only put out DC voltages between 0 and 5V. i suspect the confusion comes from what VOK does: it presumably puts out 5V when 26Vac (or anything close to that) is present from the transformer.

[Anonymous No.1874702]

>>1874697
>that transistor can only put out DC voltages between 0 and 5V
Call me stupid, but don't those two transistors make an oscillator?

[Anonymous No.1874703]

>>1874702
>Call me stupid, but don't those two transistors make an oscillator?

you're stupid! they are 2 inverters in series, that latch ON when AC is present.

[Anonymous No.1874709]

>>1874703
>they are 2 inverters in series, that latch ON when AC is present
Oh yes, that makes more sense. Couldn't have that high of an amplitude anyhow. But I don't really get the point of it, as it's latching on AC from the ±13VAC transformer winding, while it's being powered from both the +12V and +5V rails, which are both derived from that winding. I guess it's to check that the +12V and +5V regulators are working? If the +5V regulator isn't outputting 5V then the output won't show 5V but rather ~0.7V, but if the +12V regulator isn't working then the output will still be 5V. If the winding isn't working, then the whole thing will be 0V. Shoulda used an AND gate instead of a latch, what's the point of it even latching? The initial "latch" command comes from the transformer winding, which can't reasonably go off afterwards if the +12V and +5V rails that power the latch are still working.

[Anonymous No.1874714]

>>1874709

the 5V regulator looks pretty complicated. it may have some inherent delay, and they dont want things to start up before that 5V is rock solid.

[Anonymous No.1874809]

hey I have a question. I am using an eeprom that has a spi interface. I am a little confused about the clock of the spi. Would it make sense that different operations you use the eeprom for would have different clock speeds, for example fast read and read have different max clock speeds. Or should they all have the same clock speed and I’m misunderstanding what it means.

[Anonymous No.1874882]

>>1874702
>those two transistors make an oscillator?
That circuit would normally be called a Schmitt trigger.

[Anonymous No.1874913]

>>1874357
Triangle wave anon, how did you learn about musical circuits and phase and Fourier and stuff?

[Anonymous No.1874922]

new
>>1874921
>>1874921
>>1874921
>>1874921
>>1874921