/diy/ - Do It Yourself

1 bump = dead sandnigger...bogan electrician edition

How come corporations you can count on one hand get to make all of our processors?

Is there a way I could make a transparency projector that keeps a picture the same size and stay in focus at varying distances?

>>2396143
There used to be more, but people stopped buying them.

>>2396143
cutting edge processes require billion dollar fabs that only make money/stay competitive for ~5 years

>>2396151
a passive system not without a bunch of calibration that probably wont work very well.
Maybe read up on how a cameras autofocus works, and try to adapt that system/use a broken camera to work as your sensor.

>>2396143
if you think thats bad, wait till you find out how many companies make the lamps for developing dies

Reposting from >>>/sci/14529465

Could I use a ham radio transceiver (~150W) to drive a small RF plasma chamber? If so, how would I go about matching the impedance? I am very new to RF.

>>2396151
Perfect collimation may work, but it requires a lens (or mirror) as large as your desired image, so it's not very practical. Autofocus is likely not overly difficult with a stepper motor and some sensors.

>>2396192
>Could I use a ham radio transceiver (~150W) to drive a small RF plasma chamber
If the frequency is in a desired band, then almost certainly.
>how would I go about matching the impedance
A matching network, presumably. LC PI filters and the like, pretty simple for all I understand. Maybe a bit more complicated if you need to cancel out imaginary impedances at the load, but that's still pretty standard IIRC. If it needs to be variable you may have issues but with a bit of clever engineering it should be possible to make a high-power RF variable capacitor. Variable inductor is probably easier, be it for a matching network or transformer-based matching.
If you need to use negative feedback to keep the RF frequency at the ideal frequency for the chamber (changing geometry may or may not be a concern) it would be difficult but probably not impossible.

Trial and error may not be trivial though, at least not without an RF simulator. They're neat.

Also ask the ham radio thread.

>>2396183
I'll have to look into camera autofocus systems, I guess.


>>2396198
>it requires a lens (or mirror) as large as your desired image, so it's not very practical.
I'm only looking to make the image about an inch in diameter, so that's doable if I can get a lens that size.

>taking a rod of copper, connecting multimeter probe on it
>connecting 2nd multimeteer probe to Ground
>measuring AC Voltage
>Multimeter climbs up to 12V

>Connects the rod to 3rd oscilloscope's probe
>Connects 2nd oscilloscope's probe to a bench PSU, on Building Electricity line (1)
>Connects 2nd oscilloscope's probe to a bench PSU, on Building Electricity line (2)
>Line (1) and (2) are well presenting 2 phases and their shift from the distributing 3-phased cable outside
Rod is measuring a 50Hz signal around 4V amplitude.. not in phase with any of the building's lines.
>Shutting down both power lines of the building, and the rod continue to display same figures
wtf is this leakage. Producing stress in the body. How can I trace it further ?

>>2396203
Yes, but the resistance of just touching wires together may be significant enough to cause issues. And every time you connect and disconnect them you'd get little arcs that damage the surfaces.

>>2396212
Practically speaking, too easy to short them together I suspect. Also you need some good method of holding the wires onto the pads/rods.

If you're looking for convenient wire connection methods, look into wago lever nuts, those pushbutton terminals, etc.

>>2396205
>I'm only looking to make the image about an inch in diameter
Yeah basically you'd put a lens such that the effective converging point of the rays are right at the focal point of the new lens. Gaussian optical transformations may help you figure things out, though they are technically only suited for the thin lens and paraxial approximations. It should be possible to get a sufficiently sharp image, this may require putting an aperture right at that converging point. Apertures make my head spin.

>>2396211
I'm like 80% sure it's just capacitively coupled due to no common reference measurement point. Like if your scope isn't grounded.

holy shit is it really this simple to make a welder this easily and cheap with just a shitty old microwave?
https://youtu.be/fXJMCUuHmDc?t=192

I'm having trouble getting this ZVS circuit I'm working on to actually oscillate. Current seems to be only flowing on one side, in the path I outlined with the red line. I'm not sure why this is occurring. I've quintuple checked that all of my components are functioning properly, and that all of the connections are secure. What I don't understand is how power is flowing on one side only. If the main LC section isn't oscillating, then wouldn't power be flowing on both sides simultaneously?

It seems like the only troubleshooting advice out there on the internet for these circuits is to make sure you're using a fast start power supply, which I am already doing. Does anyone have an idea of what could be going wrong here?

>>2396218
>is it really this simple

nope.
you need multiple transformers in series (or parallel, or a combo of both) to get enough power to stick weld.
otherwise, you're just a kid making sparks.
(also, it's a dumb idea to cut open the transformer coz it'll never be as good when you weld it back together.)

>>2396227
I know nothing about this but if this was me fooling around in ltspice I would play around with the orientation of the diodes and maybe the mosfets

>>2396257
>I would play around with the orientation of the diodes

For the future of humanity, I hope and pray that you are not now, and never will be, an electronic designer.

>>2396227
What are the specs of your power supply?

>>2396266
Rectified and filtered output of a variac transformer. The "fast start" is that I turn it on and then connect it to the circuit. I've also tried using a battery, which didn't work either.

>>2396257
The orientation of the diodes and mosfets is definitely correct given their purpose in the circuit. Besides, it works perfectly in simulation anyway.

>>2396192
I worked on plasma etching machines....fwiw we used 10kw for the microwave, 1kw for the rf.

>>2396192
also the matchbox for rf was a big series and shunt inductor....literally big ass mechanical windings on small motors that adjusted themselves. for the microwave the reflected shit just got dumped into water as a load.

> Trying to get in to DIY effects
pedals for my DIY guitar
> Tell reddit im somewhat experienced in DIY electronics, and just want some schematics to base my first build off of, so i have an idea what's standard practice
> Reddit fags tell me to start with a "kit"
> Look up these kits
Its literally a paint by numbers / Lego style / difficulty level. Its barely DIY at all.
That hobby is dead before I even got to it.

>>2396447
http://www.generalguitargadgets.com/

>>2396227
Most likely your Q factor of the system is too low. You're not modelling parasitic resistances which are really important when determining if circuit will oscillate or not. Even couple of 1/10 ohm could be a difference between the thing working or not. Inductors have wire resistance, capacitors have ESR and you need to include all of them if you want your simulation to be more than a pretty theoretical example.

If you're feeling brave you can write out complete transfer function of tank circuit with ESR included, pic related only includes inductor parasitic resistances. This will give you Q and frequency which you can then use to determine which components you have to change to get enough Q - amplitude when transient occurs. From what I've tested the best thing is to keep resistances as low as possible and increase tank inductance. You need that peak to give you enough voltage for oscillations to sustain themselves.
>It seems like the only troubleshooting advice out there on the internet for these circuits is to make sure you're using a fast start power supply
Yes, you basically need to switch it on fast enough to generate necessary frequency components in resonance.

>>2396454
Thanks a tonne!
I have found another cool site as well
https://www.experimentalistsanonymous.com/diy/index.php?dir=Schematics/

>>2396462
Grazie, Signore. While you're here you should put this in your spank bank:
https://sound-au.com/

>>2396465
Thanks a lot. I see most circuits are quite simple. The closest I came to audio before this was the noise from a janky but functional metal detector.

I think i want to build a compressor pedal, seems like an interesting project to figure out

>>2396470
Do it up. Order bulk jellybean components and a breadboard or 3. Don't be afraid of burning anything up. Once you've committed yourself to a design, lay it out in KiCAD and use surface mount components. Then send your order to the bug colony so they can have their slaves manufacture it for you.

>>2396461
Thanks for the insight. I'll try and see if I can make a more accurate model. I don't have much experience with programs that sophisticated, so I'll have to figure that out.

>>2396473
Ive build a lot of my projects on pad per hole boards and ill probably be continuing that. Ive been looking at PWM compressors and am at least 60% convinced that the conventional design isn't optimal. Im probably going to do it "the other way around"

i'm not an electricity guy, i went to school for chem E.
but, i've been wanting to try electroplating at home. a benchtop power supply is only like 50$ or so on amazon, but i've got two questions before i pull the trigger on one.
first, what other sort of shit can i do with a bench power supply? i've done fuck-all with respect to electronics. i've played with a raspberry pi and all i know about electricity is from two mandatory physics courses.

also, i can't tell any meaningful difference between THIS bench power supply, and THAT bench power supply. what makes one good or bad?

>>2396537
>what other sort of shit can i do with a bench power supply?
You can shock your nipples off.
You can shock your balls.
You can shock your caulk.
Most importantly, you can power things with it. It's a power supply.

>>2396537
the power supply matters less than your plating solution. it takes a very specific recipe to plate shiny its really easy to plate salmon
rio grande sells it but its expensive

The control panel for my project, took me like 4-5 hours of soldering. It is basically 3 buttons and a switch. Also I OR-ed buttons together

>>2396595
Good. On the next board, use solid core wire and run them on the underside of the perfboard, and keep your layout tight and symmetrical.

>>2396605
I didn't have a solid wire, will definitely buy it and might redo this after that

Electronics adjacent:
Any code experts? Code calls for interconnected fire alarms these days. I'm doing all the data/phone wiring in my brothers new house while its studded to save money. He wants to do a Vista 20 alarm system and he asked me if we can do all smoke alarms through it. I've done this before commercially but in residential applications...do I need to install a sounder in every bedroom? Based on my read of PA code alarm panel fire is fine as interconnected UL but I can't tell whether a hallway sounder is permissible as "audible"

>>2396606
Use an old network cable in the meantime. If you're lazy or don't have time you can buy pre-stripped and bent jumper wires like pic related.

https://www.amazon.com/Elenco-Piece-Pre-formed-Jumper-Wire/dp/B0002H7AIG

>>2396227
Another anon was messing with that exact circuit a month or two ago, he found an enhanced version of it (no link sorry) which you may want to hunt through the archive for. Not that many posts with "zvs" in it to look through. Him and I tried to enhance the already enhanced circuit, and made some headway in understanding how it actually worked, but actual improvements were few.

>>2396247
>it's a dumb idea to cut open the transformer coz it'll never be as good when you weld it back together
Don't people just cut the secondary winding itself out and coil the low-gauge wire in the gap after bashing the remnants out? Cutting transformer cores isn't something I see often.

>>2396481
Get into etching anon, it's not a massive timesink I promise. Also could you elaborate on the PWM compressor method and it's alternative, because PWM in audio sounds like a fucking stupid idea.

>>2396537
Can charge batteries, test light bulbs, check what voltage something runs off best, . If you're willing to share over at the practical chemistry general, I'd love to hear about the kinds of additives you add to plating solutions.

>>2396623
Better off asking the question thread (sqtddtot), or a sparky general if there is one.

>>2396503
Pinecil is based, almost certainly the best portable iron in existence, at least below the $50 mark, and probably below the $200 mark too. Build quality looks better than both the TS100 and TS80.

If you don't need something portable then there are modern SMPS-based temperature controlled stations that are pretty decent looking, though they're made by the chinks so the QC isn't as good. The T12 station is a common one that runs at 75W or so, while the Aixun T3A is a 200W beast that uses based JBC tips.
But the Pinecil works about as well as a T12 anyhow (and for a bit cheaper IIRC), with the only downside being an arguably less user-friendly interface (buttons on the handle instead of rotary encoder on the box)

>>2396247
Is it retard proof tho? if i knock the secondary out and replace it with 3 turns of super thicc wire then it becomes safe to touch right? as in impossible to fuck up where somehow the thicc wire will have 230V in it

>>2396878
>Is it retard proof tho?

mostly.
but since you're the one who has to remove the secondary, your skill and patience matters.
in other words, dont nick the primary winding: cover it and the connecting spade terminals with tape.

>>2396878
>Is it retard proof tho?

mostly.
but since you're the one who has to remove the secondary, your skill and patience matters.
in other words, dont nick the primary winding: cover it and the connecting spade terminals with tape.

>it becomes safe to touch right

yes, electrically it's just a couple of volts, but presumably you're gonna use the 1000W to burn shit up, so gotta be careful of molten steel.

>>2396890
Is there a good source of transformers of a higher power than MOTs? Aside from broken welders I guess.

>>2396893
>a good source of transformers of a higher power than MOTs?

there's definitely sources but none that would qualify as ''good''.
that' be factories where they need all kinds of different voltages to run various machines made all over the world.
but, you need war, fires or earthquakes to get access to those. and you gotta get there before the metal scrappers.
MOTs are everywhere, sitting on curbs, so you juts gotta get a few.

Is the stuff from Iwatsu Electric any good? I only know about western (HP and Tek mostly) equipment, but I found a FC 8841 frequency counter that looks very nice. Sadly all I can find online is written in japanese, so I dont have much to go off.

Is there a way to use an inkjet printer instead of a toner for printing a circuit board?

>>2397040
I dont think the ink sticks to pcbs.

>>2397040
Yes. Never tried it myself. Search Lycos for more info.

>>2397049
>Lycos
I am gonna need a bit more info for that, never heard of it and googling stuff sucks these days.
Also if that method involve inkjet transparencies it wont work for me because getting photo developers in my country is pain in the ass, fuck i am gonna have to use muriatic acid because i cant get ferric chloride.

Is this realistic? I want to minimize the current on the load when my transistor is off, and this gives me picoA level of current when base is ground

>>2397058
forgot pic

also if I want to reduce voltage drop on a diode, what diode should I pick?

>>2397057
Can you get hydrogen peroxide? 2:1 to muriatic acid.

>>2397061
i can get that and i am planning on that, but i am asking about if it is possible to use an inkjet printer instead of a toner printer.
I also need to learn how ratios work in chemistry, i really sucked in that in HS.

>>2396794
>>>2396481 (You) #
>Get into etching anon, it's not a massive timesink I promise. Also could you elaborate on the PWM compressor method and it's alternative, because PWM in audio sounds like a fucking stupid idea.

Well, normally, theyll switch between the input voltage and ground at super sonic frequency, and then use a low pass at 20kHz to make it in to audio again, basically the proportion high (input voltage) to low (ground) determines proportional control.

My idea was delta modulation (like in a class D amplifier) and then modulating the rail voltage liinearly. I think this saves on component count, and is a bit simpler to implement, because you don't need to switch with FET's

>>2397059
The bjt switch seems sound. Schottky diodes have lower Uf, there are 2 standard ones in the Falstad library.

>>2397040
It's not waterproof enough to survive etching anyhow, unless you buy some sort of fancy inkjet ink. Gonna be expensive either way.

>>2397057
> i cant get ferric chloride.
Muriatic acid is the common method, but you can probably do membrane electrolysis with iron metal and salt water to make ferrous chloride, hydrogen gas, and sodium hydroxide. Then you just bubble air through it or leave it with the lid open for ages. Need a good membrane for that though, think terra-cotta works sufficiently well with iron compounds but I'm no expert. The high pH of the basic side may result in iron hydroxide forming, which wouldn't be ideal. Can't really acidify it though. Might be better off electrolysing salt water into sodium hydroxide and hydrochloric acid and then using that HCl to make the ferric chloride the normal way.

>>2397058
>>2397059
Read the datasheet of your chosen transistor instead of relying on a simplistic simulation. For example, a BC547 has a current of about 200pA on average, maximum of 15nA. Compare that to a BSS138 MOSFET and you've got current as high as 500nA max. Still a non-issue in most circumstances though.

Also why use a 1kΩ resistor on the base? Looks like a massive waste of current.

>>2397151
>theyll switch between the input voltage and ground at super sonic frequency, and then use a low pass at 20kHz to make it in to audio again
How is that a compressor? Just sounds like a simplistic class-D amp. I thought compressors were just automatic-gain-controllers, basically voltage-controlled-amplifiers. Maybe some nonlinearity from soft clipping too, idk. A JFET or OTA design would seem conventional. Single balanced diode mixer if you're a hipster.

Is there some other definition of compressor I'm not understanding?

>goot brand desoldering braid for 1.9USD
this staff discount is the shit

>>2397448
>does not own a cheapo vacuum pump

get a small piece of metal tube like a brake line tie wire it to the tip of your iron with the other end in a plastic tube attached to said vacuum pump. it will suck the solder off harder than your mom on rent day

the air flow from the vacuum pump also helps with heat spread unlike solder wick

>>2397452
I only use wick for SMTs anyhow, pumps aren't that useful for those from what I've found. And my shitty spring sucker is good enough for THTs.

Though I do wonder if anyone makes T12 cartridge tips designed for solder sucker vacuum tube hookup.

Why are the X and Y signals tied together through a 150k resistor?

>ZY12PDN (USB-C PD trigger) connected to fan controller connected to 12V6A blower fan
>ZY12PDN set to 9V (charger sources 3A), draws 3.6A on amp meter, runs fine
>remove amp meter, starts power cycling
>???
It starts power cycling on 12V too (charger sources 3A) but I guess that's to be expected.
If I had known USB-C PD only defines up to 3A at 9/12V I'd have bought a different fan

>>2397594
>USB-C PD
>3A
Maybe not relevant, but usb-pd devices following spec look for an e-marker in the connecting usb-c cable.
If no e-marker then assume cable can only handle 3a.
If has e-marker then follow whatever the cable says. Usually 5a.

Look for 100w capable usb-c cables for 5 amp carrying capacity.

>>2397619
Worth a shot

P.S. why do delta fans have the pwm wires as yellow, and the blue wires as tach?
it's backwards to everything else I've seen.
At least now it only power cycles when I run it at full blast

>>2397594
inline or clamp meter? if inline the added resistance of the test leads might have just squeaked you under whatever current monitor is limiting the circuit.

>>2397626
inline, so I guess that could have done it.

>>2397587
More details? What does the circuit do? If you simulated that section you'd get a pretty good idea, I suspect it just makes the two slightly proportional to one another, but the fact you'd find that in an X/Y system, let alone with an asymmetry to it (R29 compared to R36) is certainly odd.

>>2397594
Those ICs look kinda handy, and while I like the idea of just plugging anything into a universal PSU and having it automatically swap to the correct voltage, the boomer in me says it just makes for more expensive PSUs for no benefit, and to go back to mini B USB (or full sized B USB) or barrel jacks. DIN sockets are nice for multi-rail PSUs.

>>2397646
>more expensive PSUs
That's the thing
As long as you're not using more than like 3A on the low end and 5A@20V these PSUs are relatively cheap because of economy of scale and changs
I guess it can never beat being able to buy a vintage 19.7V ThinkPad adapter for $17 though.

>>2397151
why do people manually (You)? is that a newfag thing

need to change the battery for my s10e. I've been thinking of putting a magsafe compatible magnet INSIDE the phone. This comes from this video https://www.youtube.com/watch?v=Kzog61SlTyQ

Essentially one of these https://www.amazon.com/dp/B08NX5F5YP on the interior back of the s10e over the current wireless charging location.

Seems pretty cut and dry to me but just wanted to see if anyone here had any thoughts. Anything I didn't consider, problems etc.

>>2397671
The obvious issue I can see is that there may straight-up not be room for it. Phones generally have very little wasted space inside, and it's not uncommon for certain parts to be deliberately butted up against the case for thermal reasons.

>>2397671
That's not a good idea. Use wireless charging, ideally.
Alternatively, create a case that has magsafe on it and simply acts as an adapter for the actual port.

I've always thought it would be a really smart meme to create audiophile oriented cases.
Like put in the fanciest meme DAC in a case with a 3.5mm jack and watch everyone cream themselves.

>>2397682
for real though, why isn't it? Is it a theoretical issue? i.e. magnet would fuck up battery or antenna reception? or is it a practical issue like >>2397677 anon stated (i.e. might just not fit)?

I know it's not a "standard use case" but I guess I'm looking for actual reasons, theoretical or practical.
The phone does have qi wireless charging and infact the S10e has reverse wireless charging. Even in the video it states, to place it over the wireless charging spot, I guess to align the magnet coil to the charging (coil?)?

External case is the obvious idea and I have thought about it. The reason I'm thinking about this is 1) I'm going to open the thing soon anyway to replace the battery and 2) I kinda really hate cases. I have the S10e because it's compact, feels nice to hold, light. I do occasionally use a case (especially when travelling) - I use the Spigen Liquid Air Case - which while being light AND protective at the same time, still adds an uncomfortable amount of bulk (for me) to the phone.

And I totally agree on the audiophile-dac cases. I've always thought they'd be a good idea, maybe stick in a battery in it too for longer listening time? It's an idea that I think has alot of potential especially with 3.5mm removal on flagship phones.

>>2397651
>these PSUs are relatively cheap because of economy of scale and changs
Even then, meanwell PSUs with fixed output voltage are pretty damn cheap, and you can more easily build them into a project without having to faff about with USB C connectors. I can see USB C PD being preferable if you're making compact and portable projects, and also plan on swapping between different projects on one PSU, AND being projects that need more than a standard 12V or 5V wall wart can supply. I can kinda get behind the first two points, but the third? When are you ever going to have a project that needs 5A @ 20V that needs to be highly portable and swap it around a bunch? If it's a benchtop PSU or soldering iron, I'd rather have those plugged in and ready to go at the flick of a switch all the time, instead of only having one. If I'm not swapping them around all the time, better to have an integrated PSU that I didn't pay to have the ability to change output voltages on.
>I guess it can never beat being able to buy a vintage 19.7V ThinkPad adapter for $17 though.
Laptop bricks get pretty insane value per money, especially 2nd hand. Can't believe people buy nobrand laptop chargers new for like $90. They've also got decent output filtration, so you could probably use them for audio without too much work.

>>2397682
I'm looking at getting a Pinephone, removing its back cover and replacing it with one that has charging pins and magsafe-style magnets on it, along with a 3D printed charging platform that has pogo pins on it. Never going to wear out a charge port if I just use hard-gold plated pads on the back.
The Pinephone also has pins to connect sensors and such to, which I could likely do some interesting things with. If I wanted an audiophile phone it would be pretty easy to connect it up to a nice DAC and amp and cram a larger battery in the case. I'm more of a mind to connect it up to a nice ADC with a built-in microphone condenser cartridge to get high quality phone calls.

>>2397696
>Laptop bricks get pretty insane value per money
Xbox 360 power bricks supply 5V and 12V at up to 203W output depending on revision. Under $25 in the usual places.

>>2397699
>12V
>203W
What the hell, is that 16A?
>inb4 most of it's at 5V

Sounds like a good target for a SEPIC/buck-boost benchtop PSU, though maybe a higher initial voltage would be preferable to reduce MOSFET current. The output is grounded, I assume? Not like it matters.

>>2397704
2A is the maximum output on the 5V standby. The rest is allocated to the 12V output. Input is through an IEC style connector with ground lug, output is several 12V lines, 5V standby, and several grounds.

>>2397708
I ran a car taillight off mine once and fyi no, there's no earth ground on the iec style connector

>>2397713
Right. Meant to write "without ground lug", honestly. Otherwise would've written "IEC connector" instead of IEC-style connector.
My bad.

>>2397708
>>2397715
>IEC-style connector without ground lug
Ah I see, guessing it's the same as the Xbox One plug too. That's kinda odd, and while I guess there's no high-power connector without ground lugs, a C7/8 is fine up to 2.5A which more than covers the 200W limit at 120V. No point in differentiating between live and neutral either, though it's not like some connectors don't make that distinction. I wonder why...

>>2396878
>Fucking around with an MOT
>Retard proof
Nigga, you goin die

>>2397646
>More details? What does the circuit do?
This is a schematic from the manual for the tek1720 vectorscope. It was an XY input mode (meant to monitor audio but i want to drawn shapes) and this circuit represents the first stage, the outputs are then fed into amplifiers to drive the deflection plates

>design my first PCB while learning kicad
>kept as simple as possible with only 2 layers
>finally finish it after 4-5 days of screwing around with multiple revisions of track routing
>order it from JLCPCB
>it's been stuck on 'in production' for 5 days now
I WANT MY BOARDS YOU FUCKING CHINKS. REEEEEEEEEE

>>2397957
>>it's been stuck on 'in production' for 5 days now

got email saying it was ''designed so badly it keeps breaking the machine''.

>>2397957
Somebody sneezed on your PCB which caused the CCP to cremate 3 million problematic changs and their pets.
Design more PCBs.

Sorry for the noob question. Are "signal relays" latching relay? For example this one

https://www.te.com/usa-en/product-4-1393788-8.html

This remembers state right? I only need to pulse it to change its state.

I need a relay that will be only used for ICs, at 2-3 volts. It needs to be toggle able by IO pins, needs to remember its state, the link seems OK but I don't understand most of the lingo

>>2398177
What you are looking for is more commonly known as a bistable relay.
The one you linked is indeed one of those.

>>2398182
actually I looked a bit more and here it says non latching

https://www.mouser.se/ProductDetail/TE-Connectivity-PB/V23079C1103B301?qs=CNrsY6Bml5mJjfpRR1yORw%3D%3D

This means that it won't remember the state right? I need to contentiously pulse it to toggle it

>>2398184
Yes, it's not latching, it should say explicitly latching or bistable. Even if it says that magnetic system is polarized it doesn't mean it's also latching.

>>2398184
My bad, I looked at the datasheet and saw the bistable section but failed to see there's also a monostable section.

>>2398190
>>2398193
Thanks anons

I have a Manning Bowman Number 31 from I'm guessing the late 50's that I enjoy using. I recently took it apart to replace the wire nuts used by the OEM to secure the wiring with insulated spade connectors. I'm sure some here would cringe at that but I figured it's better than the wire nuts.
Anyway, the reason for the post is I lubricate this fan with machine oil on the front and rear. There is a felt pad that rides against a brash bushing that holds the motor shaft. I've noticed that there is a hum coming from the fan and was worried if it was the sound of these brass bushings being shot. This is more noticeable when I throttle the fan down with a dimmer. The fan has no power switch or speed settings, just plug in and full speed. Linked webm is the fan with sound. webm related is the fan but without sound so pointless to the question.
>>>/wsg/4555729

>>2398265
Should clarify, the electrical hum I know is normal, I mean the whining sound it makes.

>>2398265
Switch to a thicker oil. It won't fix your shot bushings(if they are actually shot, and if that whine is actually coming from them), but it'll help cushion any chattering(that whine you hear). You could try peening the edges of the bushings with a teeny tiny center punch and a teeny tiny hammer to take up any play. If the bushings aren't impossible to remove, you could search the mcmaster carr catalog, you might just luck out and find new ones of the right size. If you do end up replacing them, make sure the new ones are oilite, It'll outlast your grandchildren.

>>2398314
Thanks anon, I'll try the oil first and then look into the bushings themselves if that doesn't work.

>>2398314
A little update. I used a syringe to impregnate the felt pad with chain lub and also spread some on each side of the bushings. So far it is much quieter. Thanks anon.
An internal shot, feel free to laugh at my shit job.

>>2396447
I saw this folder on /mu/ ages ago, but it has a ton of circuit schematics for pedals and amplifiers so it might help you to look through it as a base for your own pedal designs.

>>2398369
>>2396447
Sorry, it's quite late and I forgot to post the link, here it is.
https://mega.nz/folder/KIoilagC#3KtnUYdTW53VsQu9QrJS_g

>>2398367
Looks fine and using quick disconnects was wise and based.

>>2398177
>This remembers state right?

if you have an old thermostat of this type or similar, you'll find inside 2 or 3 latching relays that work at 3V dc.
i got a couple from the thrift store for a couple of bucks.

>>2398421
Based dumpster diving advice

>>2396121
gor a bunch of digital ICs like cde4093, t74ls05 and no clue what to do.
can't find anything comprehensive in the ressources. Any project ideas? Possibly with a comprehensible explaination.
Thanks

>>2396121
add this guy to the OP:
https://danyk.cz/index_en.html

>>2396447
study the kit schematics, build your own on perfboard, reverse engineer them and modify them. don't be such a helpless little bitch.

>>2398492
Neat link, though there's a ton of sites like that if you look hard enough. I think I should start collating them into a pastebin, instead of trying to fit them all in the pastebin. Could use a github link instead of a pastebin, since I already have an account with them.
There's also:
>http://turtlesarehere.com
who does some PCB-related chemistry as well. Plus that mega link for guitar pedal circuits. Sites like these are really good for specific project ideas, though usually you find those sites by knowing what you want to do and googling it, rather than looking for stuff on a particular site. Any similar recommendations would greatly be appreciated.

Probably a good idea to list forums like AVR Freaks and EEVblog, assuming they're not in the github link in the OP already.

But I'm definitely gonna put hackaday on the project ideas section. Also I just replaced the http with https where I found it.

>>2398029
post it

>>2398485
For simple logic ICs there isn't that much useful to do with them on their own, if you're not faffing about making discrete logic clocks or computers or other senselessly obtuse projects then they're really only used as glue logic for projects that use more complicated ICs. And even for that they're arguably not fast enough, depending on the stuff you're using them to interface with. The schmitt NAND gate can make oscillators and such fairly well. That open collector inverter is kinda oddball, but you can use it as a pretty easy logic level shifter if you want to talk at 12V or whatever.
If you're after a project to use digital logic in, I'd look into making a synth sequencer.

Post more of your ICs so we can get a better idea of what they can be used for.

>>2398029
>>2398499
Yeah post it. Assuming it's not a troll.

what is this connection name and is it proprietary?

>>2398531
Those with a single center pin and two lugs on the outer shield are BNC connectors. Those with more pins are likely to be DIN connectors, except for the largest one, which I never seen, but from a quick search I found being a MIL-DTL-26482 series connector.

>>2398535
>MIL-DTL-26482
Back in WW2 we called those Johnny Bunchapins.

>>2398535
I really wish amphenol didn't rule the world of multi-pin connectors

>>2396121
I need to rewrap the windings on a stator of a motorbike, but only have thinner wire (original was 9mm, the stuff I have is 6.5mm). From what I've read this might affect the voltage generated, is there a decent way to calculate how many turns, etc, I will need? I've looked online and can only find calculators for transformers, which don't really work for what need. Will there be any other issues with rewrapping a stator with thinner wire, aside from potentially making it not handle high loads so well? (shouldn't be an issue, only planning to use it to charge battery and run ignition system, no lights or anything)

>>2398531
Fuck i used to know those smaller connectors. They lock into place when you push the cable in, and they're twin coax wires. Theyre also popular in TDR test sets and medical gear like ultrasound wands.

>>2398610
Thinner wire will give you more resistance which means voltage will drop more with higher loads. You could somewhat compensate this by increasing number of turns, but you have be careful not to exceed limits of the regulator. Voltage will be proportional to number of turns so if you increase number of turns turns by 5% your voltage will also rise by 5%.

Calculating number of turns would be a bit difficult because at minimum you need to know what kind of magnetic flux rotor generates and how fast is it rotating. The best thing to do is to just use the same number of turns or slightly more. If you don't know how many turns were there initially then next best thing is to run it with small number of turns, measure the voltage and then extrapolate to your required voltage.

>>2398599
>amphenol didn't rule the world of multi-pin connectors

they dont. they be smol potatoes compared to the mighty hirose.
https://www.hirose.com/en/product/document?clcode=&productname=&series=RM&documenttype=Catalog&lang=en&documentid=D49729_en

>>2398599
>amphenol didn't rule the world of multi-pin connectors

they dont. they be smol potatoes compared to the mighty hirose.
https://www.hirose.com/en/product/document?clcode=&productname=&series=RM&documenttype=Catalog&lang=en&documentid=D49729_en

why the fuck is it so hard to find coherent, cohesive info on building a consumer electronics oriented battery pack
I just want to put together a few lithium cells for a 20 volt 2 amp portable laptop charger, and have it act like a battery pack should (over/under discharge protection, short circuit protection, charge controlling, etc) but the literature is all written for industrial scale battery systems and nothing will give me a definitive answer as to what all circuitry I need to get/provide so that it will work like a standard plug-and-play battery pack

>>2398684
Just pick a charge controller IC and copy reference design from the datasheet or application notes.

>>2398684
There are 3 parts:
batteries
battery management system (BMS)
charger
Assuming you're using 18650 lithium cells, they are arranged in serial and/or parallel configuration, i.e. 3S2P which is 3 series cells x 2 rows wired parallel to each other. The BMS handles the protections and needs to match your specific battery's high/low cutoff voltages (3 series 18650s at full charge is between 12.6-12.9V. The charger needs enough ass to power the whole thing with the minimum available charging current per battery at 500mA.

>>2397403
It attenuates using PWM. Instead of switching between rails to get an average, it switches between a signal and ground, getting an average in between the input and ground, thus attenuating.

>>2398369
I seen that one on that experimentalist anonymous site

I came across this on one of the forums, the guy seems to be knowing what he's doing

>>2398723
Fuck, forgot link
https://www.diystompboxes.com/smfforum/index.php?topic=129221.new#new

>>2398496
I didn't realize the kits came with schematics, reasonable source of schematics tho there are easier sites

I need help /diy/. I dont want to plug my computer into AIDS infested socket
>assembled my first very own computer with great cpu etc
>move in nan's house to help grandparents out with stuff
>plug computer into socket
>touch computer, get shocked
>unplug computer, whip out multimeter
>measure voltage between Earth and Neutral, 1V, perfectly acceptable
>measure voltage between Earth and Live, 35V wtf
>plug in computer
>measure Earth-Neutral, 27V
>measure Earth Live same 35V
What the actual fuck is happening? Our mains is 50Hz 220V

>>2398751
Unplug every single device in the entire house.

>>2398757
You're scaring me anon, what do you think is the problem?
I suspect it's old wiring from the 80s which is finally showing it's age. The only question is, how does this even happen?

>>2398763
Disclaimer: Retard here. I think you have something plugged in on the same circuit that's in danger mode. Have you tried probing another outlet in a different room?

>>2398778
Just checked anon, nothing else plugged in on the socket.
Other sockets in other rooms are fine, earth-live = 240V, earth-neutral = 1V
Doesn't seem like the earthing is at fault here, it's just this one socket.

>>2398782
*Earth-live=220V

>>2398782
Throw the breaker and replace the outlet. Use the screw terminals on the side to secure the wires. DO NOT use the push fit terminals on the rear. If you notice any oxidation or melted insulation, cut away the shitty part of the wire before proceeding.
That is all. Good luck, Anon.
Is the outlet switched? Might wanna check the switch and wire condition too just in case.

>>2398751
PC psu probably has some Y rated capacitors to filter out common mode noise. Those capacitors are connected between live and chassis and most likely the reason why are you getting shocked. This means that probably there is a shitty contact on some earthing connection somewhere in the installation. Check the cable, socket and main distribution board for corrosion and other shit. I once also got same problem because IEC cable was made to chink quality standards and didn't make a proper connection to ground.

>>2398789
>>2398790
I will flip the breaker and inspect the socket. Will get back to you guys tomorrow
Thanks for the insights

>>2398790
>there is a shitty contact on some earthing connection somewhere in the installation

no, dude.
it means no earth on the socket. at all.
looking inside the socket might reveal why not.
but the ground wire could also be broken inside the wall.
simplest solution is to avoid that socket and use another.
or an external ground wire could be run from the bad socket to a good one.

>>2398790
>there is a shitty contact on some earthing connection somewhere in the installation

no, dude.
it means no earth on the socket. at all.
looking inside the socket might reveal why not.
but the ground wire could also be broken inside the wall.
simplest solution is to avoid that socket and use another.
or an external ground wire could be run from the bad socket to a good one.
(as in: using 2 dollar store extensions, make a male-male extension but only connect the neutral wire)

>>2398799
Safety first. Probe for voltage after you throw the breaker. Don't shock your balls, Anon.

>>2398800
If he is measuring 35V between live and earth there is some current path that exists, it's just really bad because he should be getting full 220V across it. If there were absolutely no earth his voltmeter wouldn't have shown anything. From safety perspective it doesn't make a difference though.

>>2398804
>If there were absolutely no earth his voltmeter wouldn't have shown anything.

that's only true if he's using an analog meter, which is improbable.
using a DMM, which has huge input impedance, will get you all kinds of phantom voltages, coz of capacitive coupling between the live and anything.
just now i measured 37Vac between live and my left hand.

>>2396227
>>2396257
>>2396266
>>2396461
>>2396794
Turns out the problem was simply that my diodes weren't fast enough for this. Once I got more appropriate ones, it worked immediately.

>>2397622
dudes we have cables with screens in them now
we're living in the future

I apologize in advance if the question that I'm about to pose is stupid, profane or downright retarded. I didn't pay attention in my HS physics class and the only reason I'm posting here is that I'm in a bit of a pinch and I'm hoping that some kind anon will point me in the right direction.
Here goes: I'm battling a solenoid valve that is causing electrical noise to be introduced into my car's electrical system. The noise manifests itself as a false RPM signal. The solenoid is controlled via PWM (around 300kHz). Through the power of the internet, I've found out that I probably need to install a flyback diode, so I did just that. I wired in a 1N4001 diode as shown in pic related. However, while it did help reduce the noise (it now appears intermittently and less frequently), it did not make the problem go away altogether. My main question is this - is there a diode with different characteristics that would somehow filter the noise better? I also wonder if there are other things I can do to reduce the noise, or even if the solenoid valve has gone bad and a new one would be far less noisy.
Thanks in advance to anyone who bothers to read or reply.

>>2398836
>The solenoid is controlled via PWM (around 300kHz)
Here's your problem.
A solenoid is supposed to be a simple on/off device, switching on and off at a few dozen Hz at most.
By feeding it PWM the coil behaves like a transformer and induces noise in whatever is near it.
Either you shield the cables that are running close to the solenoid or you switch it with a simple DC voltage, no PWM fuckery.

>>2398837
It's a stock Toyota intake air control valve, so it must work somehow. The problem only appeared when I switched to an aftermarket ECU. I guess that it lacks some kind of circuitry for noise filtration that the stock ECU had (though my guess could be way off).
You can read a little bit about the operation of such valves on this site: https://alflash.com.ua/idlet.htm

>>2398836
>>2398837
I was also confused by this. why PWM a solenoid? If you're trying to PWM a larger load, go with a mosfet. They may seem intimidating at first if you've only ever dealt with solenoids, but the wiring is actually simpler.

If you're still hellbent on PWMing a solenoid, shield the entire thing inside a conductive housing and then ground it. Also go for a higher value diode.

>>2398840
Ah, an actual solenoid valve. Gotcha. Yeah you're probably going to need some capacitance leading to your solenoid. It'll turn your on-off PWM into a smoother signal with varying voltage that won't induce so much RF

>>2398843
Any idea how big of a capacitor I could need? The voltage of the circuit is obviously 12V, and the manual indicates that the resistance of the solenoid is supposed to be in the range between 19.3 and 22.3 ohm.
Also you mentioned using a higher value diode. Which value exactly am I looking for? The amperage?

>>2398843
>capacitance leading to your solenoid
Won't this change the parameters in the ECU and return inaccurate values of certain sensors?

>>2398849
>what is a diode

>>2398851
Explain it to me like I'm a zika baby, professor.
Pro tip: I'm a zika baby.

>>2398840
>The problem only appeared when I switched to an aftermarket ECU
Does new ECU has any settings for frequency of the output signal? It might be too fast which would cause more interference.

>>2398856
It does. Before installing the flyback diode, I tried running the valve at 120Hz and the noise was still very much there. However I haven't tried lowering the frequency after adding the diode.
I really wanted to run the valve at somewhere around the 300kHz mark, as people online have said that the valve works best at this frequency. Apparently at lower frequencies, changing the duty cycle even by 1% can make the valve move too much, which causes spikes in engine speed.
But if I can't find a good solution to use higher frequencies while keeping the electrical noise to a minimum, I'm gonna have to try lowering the frequency.

>>2398861
Control the solenoid with a FET. PWM the man-in-the-middle.

>>2398835
Those cables spy on you while you're pooping.
Ask me how I know.

>>2398863
That sounds kinda difficult, but I'll keep that in mind. I suppose I should just try finding a diagram of a mosfet solenoid valve driver on Google and build it myself?
Someone ITT suggested I simply add a capacitor and/or use a higher value flyback diode (not sure what value to look for though). Would that not work in your opinion?

>>2398876
The flyback diode just prevents back-EMF from raping your ECU. Capacitors have a frequency component and will alter the PWM signal.
https://www.embeddedrelated.com/showarticle/77.php

>>2398883
Interesting, because me adding the flyback diode really seemed to reduce the noise, plus it stopped the valve from buzzing. Maybe it's just a coincidence.
Thanks for the link, I'll read that.

>>2398883
Alright, so after reading the article, seems that all I need is a mosfet and two resistors? Unless of course there are nuances related to an electromagnet being switched at a high frequency which would make the simple circuit shown in the article not viable for my application.

>>2398861
>I tried running the valve at 120Hz and the noise was still very much there.
Makes sense. If signal has fast edges it wouldn't really matter if pulses happen at 120 or 300kHz because in both cases the edge is what's causing noise.

Here is simulation of what might be happening with your system. Ringing on voltage bus will happen due to parasitic elements of the wire and solenoid. If you add a diode, you mainly prevent big voltage spikes on the pin which might introduce additional noise, but noise on supply line will still remain. You should be able to fix it by adding a capacitor close to solenoid to ground like in third example. Try adding 10-100nF from solenoid voltage supply to ground and see if it helps.

>>2398830
Ha— it was the diodes!

>>2398896
You still need the flyback diode parallel to the solenoid coil to protect the FET from back-EMF.

>>2398899
Awesome, thanks. I'll try this first thing on Monday when I get to my garage.
Btw, what about capacitors C2, C3 and C4 in your example, do I not need those as they would alter the PWM signal?

>>2398907
Right, forgot to mention the diode. I'll probably first try adding a capacitor from the solenoid power supply to ground, as the other anon suggested. But if that doesn't work, I'm gonna go with the mosfet.

>>2398918
Sounds good.

>>2398912
Those capacitors are parasitic capacitances of inductor. Every inductor has parasitic resistance and capacitance and you need to include those when doing simulations if you want somewhat realistic results. Parasitic resistance comes from resistance of the wire used in the solenoid inductor and parasitic capacitance comes from capacitance between each winding. C2, R6 and L5 for example form a model of coil used in the solenoid, in reality those three elements don't exist separately but are just approximations of a real coil.

>>2398630
cheers anon, figured it probably wouldn't be too easy. Would have tried winding them and testing it but the rest of the engine is still in pieces and all the poles are done with one length of wire so I'd waste quite a bit if I got it too short. I'll probably just order some wire o the correct gauge and do it properly, last thing I want is to be chasing ignition system troubles due to low voltage

>>2398939
Ohh, that makes sense. Thanks for taking the time to explain

>>2398723
runoffgroove.com has a few original circuits. At least one of them was copied by established 'boutique' makers.

It is Friday night and I am messing with latex fonts. Do you like Euler style upright integrals?
It is /ohm/ related btw. So rms = 0.707 in case you weren't sure.

>>2396121
hey guys
Newfag to electronics here. I've been trying to figure out what's wrong with this diagram for weeks. I've checked every resource I can get my hands on and I can't figure out how this violates the NEC. Any help?

>>2399092
>latex fonts
do comic sans lmao

>>2399101
I don't want to be a dick but from the OP
>household/premises wiring?
>More rules-driven than engineering, try /qtddtot/ or sparky general first

>>2398861
>people online say it works best at this frequency
I need to look into this, because either TRD solenoids are so well designed they can be used to make SMPS or class-D designs, or autofags are full of shit.

>>2399101
bathrooms require an extractor/vent if no window
bathroom circuits require afci
not clear whats happening with 2/3 gfci, presumably the two in one room are fed from one gfci socket and the other room is not fed from the first gfci otherwise you would have to go into the other room to reset it and they don't descriminate

I recently received one of picrel (pic not mine), and I'm trying to think of projects to do with it; and since I'm a complete newfag, I haven't been able to think of much. Anyone have any ideas?

>>2399176
What is it? What's so interesting about it? Just another old circuit-bending sound circuit?

>>2399176
>Anyone have any ideas?

if you have 2 stations, then you can use it for espionage.
like recording your roommate cheating, then blackmailing them to do all your laundry.
i use something similar when i'm in the garage working, and my GF is in the kitchen upstairs.
so she can order me about without having to yell down the stairs, and me saying, "WOT YOU SAY, CUNT?" 50 times.

>>2398531
Those are Lemo connectors, I think.

>>2399176
I had a set of 5 of those back in the day
You arent going to do shit with a single one

I threw them all away

>>2399303
Yeah that's what I was trying to remember.
>>2398620

You can get them with quite a few pins and they push lock

Im trying to make up a concept for a photovoltaic system for our house. Id go for 48V jsut for the flexible wires, but Im stuck on hybrid vs discrete inverters. Should I go for hybrid (ie makes 220v AC and 48V DC from solar voltage) or for discrete (one converter turns solar DC into 48V DC system voltage, and an inverter turns 48V into 220V)?
My issue is that well have multiple strings of solar cells at different voltages (different orientation and numbers), and hybrid inverters dont have enough solar inputs to accomodate all.

>>2399471
Why would you need 48V DC anyways? Surely you don't have that many batteries in series, right?

>>2399563
Not really important to the question at hand, but Id go for packs of 2 of those 24v 200ah lfp rv batteries, that should give me "packs" in the 10kwh capacity

>>2396121
BROS, I PUT DIAELECTRIC GREASE ON THE PRONGS OF AN AC CONDENSER FAN CAPACITOR...
PLEASE TELL ME THE BUILDING WON'T BURN DOWN..

>>2399615
>DIAELECTRIC GREASE

typically this takes 8 months to become flammable.
so by next summer, no one will remember who the pyromaniac who worked on it was.

Is there a resettable circuit breaker for low amperage? Like 100-250mA? I want to use one while experimenting with stuff and not low up my circuits or the battery in case I short circuit and not notice

If so is there a name for them that I can search for?

To clarify... having one audio effect with split supply won't mess up the rest of my effects chain that does not use it, right?

My plan is to replace pic related with Sony US18650VTC4

Can someone confirm this is safe? I matched capacity and voltage. I'm not sure about max continuous current.

>>2399634
>right?

yep, the caps on the outputs and inputs are there so that DC component of the signal is isolated from one pedal to the next.

>>2399634
Just make sure each effect has an isolated supply. If not, sharing the ground between different effects through the audio cable can cause problems. It's possible to be smarter about this if you know what's going on inside the effects, of course.

>>2399656
Read the datasheet of the new cell for current rating, and see if it's more or less than the maximum current required by the device itself. Chances are it will be fine, but you should still check, especially if it's a high-current device like a high-power flashlight or vape.

>>2399793
I think I need to figure out which component handles charging and look at the datasheet for that. I'm reverse engineering something here >>>2397360

>>2399656
to add on to this, what's the most professional way I can attach wires to an 18650? Pay someone to spot weld? Trying to avoid makeshift solutions.

>>2399853
(diy) spotwelder is the best way, soldering is bad for the cells

I have some wire that has some brown oxidation. What can I do to get a good surface to crimp to? The wire is rather large and fine-strand so I would rather not replace it if I can get away with it

>>2399862
dip it in/apply hot solder? maybe put flux on it first

Is there any good cheapo ($20-30) multimeter at ali?

>>2399934
DT-832 is good beater multimeter from ali
Sanwa PM3 is my favorite pocket multimeter

>>2399853
A cold bismuth soldering alloy with pre-fluxing before pre-tinning should be fast enough to not damage the internals of the cell appreciably. Can probably get away with normal solder if you're confident. There's always battery snaps, if there's room. Or replacing with a cylindrical cell that already has wires/nickel tabs, or a lipo.

>>2399934
Aneng AN8009 is a common recommendation here. Great specs for the price.

>>2399934
>cheapo...multimeter

anything beyond this is probably overkill for your situation.

Which type of motor is this? brushed or brushless?. and what the use of these grey wire?.
i googled the ref(epson sm-E48B C6C10) and found nothing.

>>2399853
>what's the most professional way I can attach wires to an 18650?
Spot welding. Any other method is either damaging to the cells or a waste of time/pain in the ass.
Depending on how much welding you need to do, you can either get a professionally DIY'd one (I have one of these, link below) or you can buy a supercap, attach some beefy leads to it and use that to spot weld. The supercap would need to be charged manually but if you have only a couple welds at a time to do then it works as a budget version.

https://malectrics.eu/product/diy-arduino-battery-spot-welder-kit-v3-2-2-full_bundle_car_battery/

>>2400045
Does it cog when you rotate it? Put a multimeter on the wires and spin it to see if it outputs AC or DC. If it's from a printer I'd guess it to be a stepper or maybe brushless servo, though it could be brushed if it's just doing initial paper feeding or something else that doesn't need to be precise.

i saw this guy add an interlock feature to the IR2110 gate driver, so HI and LOW inputs to the IR2110 (from a microcontroller) can't simultaneously be turned on at once. pic related.

>74HC00N is a quad 2-input NAND gate that acts like a cross-locking circuit. A by-product of this schematic is inverting the signal, so we need to invert the actual input signal before. When IN HI is low (for example) – output pins 6 and 8 are in the high state, and pin 6 drives IR2110 ENABLE HI input. Simultaneously, pin 8 activates the T2 transistor, which pulls down ENABLE LOW line, which protects this line from unauthorized activation.

isn't this a bad idea since it's essentially shorting a GPIO straight to ground if HI and LOW are both enabled?

>>2400045
"Ink key motor" manufactured by Shinshu Seiki. Third wire is either feedback from a tach (hall effect sensor) or PWM modulation input (transistor). Brushless DC.
*All of this is guesswork. lmao

>>2400099
It is a bit of a questionable decision since it would be simpler just to use logic gates by themselves. You need to realize function (High & ~Low) = High_out.
You can use 1 nand to negate Low and then realize ~(High & (Low nand Low)) and then negate again with transistor.

>>2400099
well it will short the output from the and gate but i wouldn't call that a gpio. if the gate ic has output current maximum and you exceed it then you can't rely on its behaviour.

Bros what is this component?
My current theory is some kind of cheap chinky solution to a variable resistor, you want more resistance you just add more of these foil layers inside
but idk man
it's out of a rice cooker

>>2400273
It's a heating element.

>>2400304
o i c
That makes sense, I wanted to disable the keep warm setting and this was on the net it switched to in that mode. I figured it just hooked back into the main heating element with a lower voltage to lower the temp but I guess they use a whole separate element for it.

>>2400310
Yessir. You put 20V/2A (40 Watts) into it and it gets warm. Similar to a heating pad for backaches or germinating seeds.

>>2400315
Handy. I'll hang on to it so.

>>2400206
i feel like a complete retard, but can you please draw this out for me? i tried making up a logic gate scheme to do this yesterday but i couldn't figure it out (much less a symmetrical scheme to get somewhat matched propagation delays.)

>>2400316
Maybe you could use it as a defroster for high-altitude projects or drying condensation on camera lenses.

What is this autism? Why do they multiply by jwRC instead of dividing through by R?

>>2400315
that's 220V/0.2A

>>2400048
thanks. I'm just trying to source someone to do it. It's a one-off project and I dont have time to dick around. Forgive my hybrid DIY mentality

>>2399656
one more question: how to figure out what the yellow wire is for? Is it safe to peel off the cover of the battery?

>>2400342
>Why do they multiply by jwRC instead of dividing through by R?
very rusty but I think they do it to so it's in the correct form. You can then find the zeros and the poles.

could some anon please provide me with ohms law written out in field equations? want to use it to show students that ohms law is a simplification

>>2400521
Google that phrase and there are examples because I just did.

>>2400319
never mind, think i got it. if anyone else cares, this is drawn using www.logic.ly -- bit faster/easier to use than falstad for basic logic gates. thanks!

Pretty much every security camera is proprietary and sends info or needs an internet connection. What's the best way to build a battery powered camera? Do I wire a lens to a single board computer somehow and then transfer the data via wifi or how do I do it?

>>2400552
>not using based logisim evolution

>>2400561
>Pretty much every security camera is proprietary and sends info or needs an internet connection
Not the old CCTV style systems, which are definitely still being manufactured these days. It's just an analog video signal on some 75Ω coax. If you want to transmit such a video signal, see what the /rcg/ guys do for their fpv setups. Basically the same thing, but with an RF transmitter and receiver.

Video over IP also works, and gets better quality, but it's more complicated. There should be plug-and-play wireless digital video solutions that aren't reliant on botnet home automation/iot services.

I traced part of the pcb from a practice amp because I wanted to find out if I could make it sound better somehow. Now, based on online clips—which I listened to on phone speakers— this amp sounds good-ish when cranked, similar in that aspect to an old vacuum tube amp. Even the "overdrive" channel sounds better with the volume cranked. Otherwise, the overdrive sounds really nasty.
Right off the bat, I think I could increase R3 to a more typical 1Meg and maybe also R8. I could mess around with the feedback resistors and capacitors, maybe replace R7 with a pot for gain control. Swap all the 1uF caps with polyester caps.
One mod suggested online for this amp model is to swap the speaker for a higher quality one. Another is to cut the diodes for higher output and less ugly distortion. Buying a speaker is not feasible right now, and I want to keep the diodes... maybe put them in the feedback loop if possible for soft clipping.

I would like to know:
-Why C1 is oriented that way
-What C28 and C27 are doing
-Anything else that I could do to improve the sound.

I mostly care about fixing the overdrive/clipping stage, but I also want to have more overall high end sparkle from the clean mode.

*I forgot to write the value of C1 and forgot what exactly it is, but I vaguely remember that it's larger than .1 uF.

>>2399176
Would it work with a PA speaker for a CB?

>>2400521
Deriving it from field equations shows that the lumped component model is an approximation. If you write it out using field equations, you still end up with a concept of resistivity (or conductivity). Ohm's law is essentially the statement that current is proportional to EMF (or in terms of fields, that current density is proportional to field strength). Which is an empirical model, not a physical law.

>>2400561
HD over coax exists but you need the proper DVR.

How does a US NEMA 6-50 240v outlet work if it has no neutral?

>>2400757
>Why C1 is oriented that way
It's retarded to use a polar cap for DC-blocking in a split-supply pedal, ignore it. In fact, you could argue that it would work fine without it entirely, same for C3, C8, and C9. C7 and C5 have some nontrivial impedance at audio frequencies so they need to stay, but I'd definitely consider removing C1, C3, C8, and C9.
Well removing the output caps only works assuming IC2 and (maybe) IC3 are split-rail. They might not be, especially IC3 since most headphone/speaker amps are single-rail. If not, say what IC it is because I'd like a few of those.
>what C28 and C27 are doing
During negative feedback, the inverting and non-inverting inputs should be expected to be equal. I suspect the caps are to help prevent momentary saturation resulting from sudden transients or otherwise high slew-rates. It is a bit strange though.

>Anything else that I could do to improve the sound
As you alluded to, putting the diodes across R7 will give a different sound. Series resistors with the diodes would also give a softer sound. Swapping the diodes for LEDs or zeners or whatever might make the clipping harsher, in case you wanted that.

>>2400790
Google "split-phase mains". Basically, there's two lives that are 180° out of phase from one another. Either live to neutral is 120Vrms, but measuring between the two lives is 240Vrms.

i.e. the residential transformer is centre-tap

>>2400790
The same way you can get 24V by connecting a +12V source and a -12V source. The 2 120V phases are out of phase by 180 degrees so when one is at positive voltage the other is negative and they add up. This is why they don't need a neutral.
Some applications of the european 3 phase 400V system (3 230V phases 120 degrees apart) also don't require neutral (ex: motors) but all outlets come with a neutral by default.

I'm in the market for another KVM switch, just a simple USB one. Most of the ones on the market that are within a decent price range have the button on the device itself, rather than on some extension (which is what I prefer).

Question is: Would there be any power problems with effectively cracking the thing open and soldering on an extension cable to a button say 60cm away? The non-retarded part of my brain says yes because of resistance, but I wouldn't know how improve it. Any ideas?

>>2400561
>What's the best way to build a battery powered camera?

easy. get one of these, or similar. there are lots like it.
you can set it up for timed images, and/or motion detection.
saves all pics and video locally on micro-SD, but lets you access them from a browser or smartphone.
if you're very keen, you can set it up to FTP every video or pic to a server automatically.
just needs a 5V power bank.

>>2400861
>Any ideas?

just do it.
you're just adding a few feet of wire which has negligible resistance.
there are some models that let you switch using a combination of typed keys, like alt-shift-scroll lock

>>2400770
>Would it work with a PA speaker for a CB?

if the question is actually ''...as a PA speaker'' then no coz it's under-powered for that.
it's for desktop use, not for full-room use.

>>2400871
>there are some models that let you switch using a combination of typed keys, like alt-shift-scroll lock
There are, but I'm a little cautious about those solutions. I *assume* the way that's controlled is through software on the computers, I run Linux and the likelihood of software support is low.

>>2400891
Change the button to an IR switch and use a remote.

>>2400861
The 4 PC one I have has a "remote" button. The cable could be much longer.
Be careful with these though as they are known to feed voltage back up the USB plug. Some machine don't like that any at worse it may fry the port. I use a sacrificial powered hub on each port to remove that power from reaching the PC.

so i got meself a camera for my miscroscope
it's not amazing, but for fifty bucks it works pretty ok, this is so much fucking better than trying to align my phone camera with the eye piece to get a sniper scope picture of my shit
any of you use these chinks cameras? is there any settings tricks to improve the picture further? if i for example pump the light on the ring to maximum the pic looks too flooded on the camera

>>2400861
Electrically there shouldnt be an issue, question is if you can crack it open without breaking it totally.
Also: what does one need a pure USB KVM for? With VGA/DP I get it, but can you transfer/control just over USB?

>>2400924
welp i think i tuned it in pretty well, that will do for now, i managed to get it to be in focus at the same time the eye pieces are

>>2400813
Hypothetically, frequency aside, how would somebody connect a British 240 appliance to such a NEMA 6-50?

Or 14-50?

>>2400891
>I run Linux

Linux Schminix.
the switching is done at the hardware layer; the OS is not involved.
i.e. keyboards are hard-coded to generate the exact same key codes irrespective of OS.
that's why you can use the keyboard in BIOS even before loading the OS.

>>2400974
you dont, since a british aplliance wants +-240 and 0 (neutral). What do you want to hook up? Water boiler? Better to use a step up transformer.

>>2400981
So let's say something else.
What about connecting something more universal like a laptop AC to DC adapter?

>>2400993
Thats not an "adapter", thats a power supply. Still needs neutral, but those are usually multivoltage (so you can use them anywhere from japan (100v) to britain (240v))
Look at the specs (should be printed on), and it should read "100-240v" input.

>>2400974
>how would somebody connect a British 240 appliance to such a NEMA 6-50?
By nigger rigging your own adapter cable.

>>2401034
please dont unless you know what youre doing, big difference in single phase vs 2-phase power.

>>2401031
It's a transformer or adapter.
It doesn't supply anything.

A power plant or a battery is a supply.

>>2401031
But how would you feed it 240 from the different phases?

>>2401098
A transformer is AC-AC, and adapter is a physical change in cabling. Whats the box in your PC with all the cables called? A power supply (unit).

>>2401101
You dont. You give it 110 line with a plug adpater or the correct cable in case yours has a changeable cord.

>>2401105
We're talking about laptops here.

There's no way to bring 2 phase power to a laptop "brick"?

>>2401115
i know were talking about laptops, doesnt change the fact. Why do you want 240 anyway? If you´re in the US or whereever they have 110V, just plug it in at 110V. It´ll work just fine.

>>2400974
Easy, just terminate your own cable. Assuming 240VAC is within the allowable input voltage range, and it doesn't use power factor correction.

>>2400981
Are you retarded? The potential is 240Vrms either way, not like neutral is ever needed to be at a fixed 0V potential, that's what protective earth is for. Assuming the thing even needs it. X and Y caps are symmetric about ground either way so there's no issue of having "neutral" being 120VAC, and double insulated tools (like laptop bricks) just leave the output floating. Arguably running an ungrounded laptop brick off split-phase 240V will be slightly safer than running one off euro 240V, since the output will float about halfway between the two input voltages and hence be much closer to 0V.

>>2401258
depends if british plugs are flippable like euro ones or if they arent. Then its isolated only one way, which would be bad. It should work, but its not worth the effort if you can just plug it into a normal socket.

>>2401262
The Nema 6-50 has a ground pin.

I'm assuming the anon want sot power up an appliance that's rated at 240V only and doesn't want to buy an expensive and bulky transformer.

>>2400926
not him, but hardware KVMs are nice because you don't have to rely on the OS, or the administrator of the OS, to understand that it needs to play nice and share a keyboard

>>2401287
Its a laptop PSU which all should be universal voltage. Thats why Im so hesitant in telling him "just cut up your working line voltage cable and jerry rig something" when he cant be bothered to read the writing on the box.

>>2401288
I got that about KVMs but wouldnt you need graphics output too? Thats why I asked about USB-only ones.

Dumb question: I’m learning about electronics to make an arduino project. My experience is more in programming and design. I know about current / resistance / voltage. How do I know when I need a resistor and for that matter how do I calculate which kind of resistor I will need? Any help is much appreciated

>>2401363
>how do I calculate which kind of resistor

when you're this much of a noob, you are incapable of calculating anything.
just follow a design that someone who is less nooby did, and who already did all the calculations for you.
in less than a decade, you'll have read enough, and experimented enough, to be a licensed resistor chooser.

>>2401363
>how do I calculate which kind of resistor

when you're this much of a noob, you are incapable of calculating anything.
just follow a design that someone who is less nooby did, and who already did all the calculations for you.
in less than a decade, you should have read enough, and experimented enough, to qualify as a licensed resistor chooser.

>>2401289
Oh yeah, using a travel adapter with an SMPS is going to work fine if it’s just for a laptop brick.

>>2401363
You know Ohm’s law I suspect, but have you done Kirchhoff’s laws? Once you have a thorough understanding of the theory, the practical implementations should be somewhat evident, and you’ll be able to calculate for yourself whether what you’ve planned is suitable.

Any particular examples you’re wondering about? If not you can try learning about simple situations like the voltage divider, LED current limiting, a heating element, maybe a low-pass filter or op-amp circuit.

>>2400805
Traced the power section today... maybe more than that.
The internet says that that particular speaker amp IC has been discontinued.

>>2401536
tayda has ones in stock made by UTC

>>2401536
>TDA2030A
Yeah that's just made with its own DC biasing in mind, just like an LM368. Might be possible to run them without a cap, but it might be kinda sketchy so I'd keep the cap and make it non-polar.

What's IC2, a dual op-amp?

>>2401564
Yes. It's identical to IC1.
Is there a way to know how much voltage is going to the ICs? There are no markings on the transformer, but I did measure 69 Ohms on the primary winding and 2 Ohms on the secondary.

>>2401596
>Is there a way to know how much voltage is going to the ICs?
Not without measuring it. You can put maximum and minimum values based on the capacitor voltage ratings and the IC voltage ratings.

so if i want to solder bgas, if i get that small chink reflow oven i technically just place the chip on the pad and it solders it self since it has solder balls right?
the probematic part is that i hate using solder paste because it expires so fast, only lasts a few months and you need to make fucking templates for applying it which sucks dick if you only want to make one pcb

Will this antenna connector footprint work fine?
it's on the other side of the pcb just under the antenna pin, which is on bottom right

>>2401648
Could invest in a paste mixer. I think the only issue with solder paste is that it separates, so if you can remix it it should last indefinitely. Or at least as long as the flux itself lasts.

>>2401657
If it's only radio at 100MHz or so then board design is noncritical and impedance matching flat out doesn't matter. If it's over 1GHz or so then you need to care about it, in which case I'd just flip it 90° to have the via and signal pad right opposite the castellated pad. Which might be a good idea anyhow, hollow vias or not.
Also I'd only use an SMD antenna connection if it's not going to see any knocks or bumps or tugs.

>>2401658
>If it's only radio at 100MHz or s
it's 868mhz lora antenna, basically the antenna connection will be there so i can connect the standard mini sma antennas to it if i need a signal boost, but in most of the times i will be using a piece of wire soldered directly to the pin when the module doesn't need to reach huge distances

>>2401658
>indefinitely
the flux would chemically react with the other shit, so just mixing it up isn't enough

>>2401536

your caps are drawn wrong.
flat side is positive.

>>2401536

your caps are drawn wrong.
flat side is positive.
unless they're transgender.

>>2401664
>868mhz
If you keep the traces short (below 30mm) then there's no issue.

>>2401667
Depends on what flux you use, but generally at room temperature they'll last ages. Solid solder just isn't very reactive, especially in the absence of an oxidiser. Put it in the freezer if you're worried.

>>2401672
was this really worth the repost

>>2401672
>worth the repost

yep, needed a punchline.

>>2401677
Death is easy, comedy is hard.

>>2401677
Dying is easy, comedy is hard

>>2401732
Dying isn't always easy. Comedy isn't always hard.
Especially when you cut your dick off lmao.

>>2398503
>senseless obtuse projects
wasn't that how everything was done back in the day? what did they do without microcontrollers?
>synth sequencer
that sounds pretty neat. it looks like I have everything except the ne556 which I can propably supplement with two 555s.
I hope it isn't too advanced for me.
https://www.instructables.com/Parallel-Sequencer-Synth/
Will update when I looked into it

>>2396121
starting to learn about switchmode power supplies. i see a lot of the pwm control ICs have a "maximum PWM" of 50% or 100%. how do you typically choose what % you need?

>>2401962
PWM duty cycle is constantly changing depending on what load is connected to the supply. It also depends on your inductor value.

>>2402028
why wouldn't you always choose a PWM chip that can do up to 100%? wouldn't the chip use feedback to regulate to whatever % it needs? or is it more complex than this?

>>2402053
>why wouldn't you always choose a PWM chip that can do up to 100%?
It depends of what kind of topology you're working with. 2-switch forward for example where giving it more that 50% would actually saturate the inductor and destroy your transistors.
>wouldn't the chip use feedback to regulate to whatever % it needs?
Yes, that's how PWM changes to follow the voltage set point.
>or is it more complex than this?
It can be, some regulators for example use burst mode and other tricks to optimize regulation.

>>2401818
>wasn't that how everything was done back in the day
I'm not saying logic ICs weren't useful, just that they aren't useful today. Even without microcontrollers, there are plenty of special-purpose ICs (SPICs) that operate on a higher level than discrete logic that are useful. Like clock dividers or BCD-to-7-seg decoders.
> I have everything except the ne556 which I can propably supplement with two 555s
Yeah they're functionally identical. I'd look around at a bunch of different sequencer (and VCO) designs to see what strikes your fancy, and understand what alternatives can be made. Also that model uses BJTs instead of messing around with analog switches, which is kinda strange but I guess it works.
The gold standard for a sequencer is to output a sequence of voltages that you can pipe to any desired volt-per-octave VCO. 555s are not very linear VCOs, nor are they particularly good sounding.

>>2401962
Over 50% can lead to instability for some topologies (current-mode boost IIRC), which need a feedback network to be stable. Current-mode is still probably the way to go though, and you'll want a somewhat wide frequency range so you can have more freedom in choosing inductors and MOSFETs.

>>2396227
Time constant in your simulation is too long. Make the first time step 1e-9.

>>2401258
So it's ok with putting it into the + and - of the 240 outlet then?

If it's that simple, then cool.

Otherwise I was wondering about bringing the two phases into a 1:1 transformer.

But if I don't have to, then ok.

Sorry if I'm a bit of a knob about this.

>>2402199
>So it's ok with putting it into the + and - of the 240 outlet then?
Yeah, no transformer needed. But it's only worth doing if you actually need 240V. A lot of appliances run off 120VAC just fine, that includes a vast majority of laptop chargers.

>>2402209
Yeah.
Wish I had found this video sooner.
https://youtu.be/JZChbvVgPJY

This is the last of the practice amp pcb. Even before firing up LT spice, I knew the filter after IC2a seemed familiar. It's a notch filter similar to the one in the Condor circuit I posted about before. IC2b is just another amplifier. I guess it keeps the impedance low for the power amplifier?
I played around with the power supply in LTspice and it seems that changing stuff alters the response of the circuit. I didn't know that could happen. I thought the power supply was just for powering stuff and forgetting it exists.

>>2402226
What do you use that melting pot for?
lools kinda dangerous

How much backlash does solenoid like this produce? if i put it on a controller in vr will it be able to simulate nice feedback to look like gun recoil?
https://www.aliexpress.com/item/32731717962.html

>>2402461
obviously i know it won't be as strong as a real gun, i am just looking for enough feedback to flinch the hand a little
normal vibration motors are shit for simualting recoild

Is it possible to do a small key finder with "long" range (~100m)?
I have a tiny cat and a very big yard with lots of trees. I need to find it when it hides out there. I looked at some XLC-RF-5V but their range is shit.
Most commercial options are too big for my cat or have very small range. I guess it's impossible to get more power on such a small device, but any input is welcome.
Thanks.

>>2402461
>1.8A
You can almost certainly give it like 10A for a fraction of a second to get a strong impulse without overheating. You'll need to fine-tune the duration, the current, and the mass on the solenoid itself. I'd lean towards as short a time span as possible, limited by the solenoid getting to full extension while the coil is still turned on (10-100ms I'd guess). Get the 6V one and measure the time it takes to heat up and cool down. Should be able to estimate its heat capacity and thermal resistance to ambient from that, which should together give you a relationship between voltage and maximum pulse length.
FYI, if you fire a solenoid in quick succession your freewheel diode may get kinda toasty, may want to put a power resistor in series with it or use a TO-220-2. Or better still, power it with a MOSFET half-bridge.

Also I'd use a solenoid as the trigger itself, you can use them as position sensors with a hall-sensor (or by measuring the solenoid's inductance), and you can give a small kick of mock mechanical feedback when pulled. I'd have a slight delay between the trigger feedback and the recoil from the "slide". Could even get a nice 3-round-burst in before the recoil hits.

>>2402476
I don't know of anything good for this off the shelf, but it may be possible to design one.
I'd use a loop rectenna around the collar for energy harvesting, a supercap for storage, and have it transmit an RF chirp when it receives a signal. You'd then find that chirp with a pair of directional antennae like those WWII radiocompass things.

>>2402482
>You can almost certainly give it like 10A
oh yeah i haven't even considered i can overload it for a shorted period of time, but do you think the kick will be strong enough?

>>2402485
>do you think the kick will be strong enough
When overloaded, probably. 450g of force is a fair bit, though I'm not sure which that one is for. You can probably give it a back of the envelope calculation for impulse/momentum based off the actuation force and resultant acceleration and travel distance (assuming force tapers off linearly I guess) to see what speed it will be at when it hits the end. Multiply that by a current overdrive factor. Can equate impulses by dropping weights into your hand from specific heights.

I'd buy some anyhow since it will certainly be enough for the trigger either way (if you can fit it). They're also just handy to have around.

>>2402121
But you still learn a good deal about the inner workings of computers and digital electronics using simple logic ICs, right?
>The gold standard for a sequencer is to output a sequence of voltages that you can pipe to any desired volt-per-octave VCO. 555s are not very linear VCOs, nor are they particularly good sounding.
I would be satisfied if it works at all. Though more sequences would be nice of course.
I will look at other designs when I get this thing working.
For now I'm confused about all those different digital ICs in existence. For example what's the difference between all these CD40...?
The sequencer design in the instructable uses a CD40106 but the only thing I have coming close to that digit are CD4093... sorry I'm too retarded to read datasheets. I don't know if these digits have any meaning or if there is any similarity at all between these ICs.

>>2402515
>sorry I'm too retarded to read datasheets.
Then you should forget about using logic ICs.

And in general, part numbers have no meaning beyond identifying the component, and if you can't get any information from a data sheet then the part number has no meaning whatsoever.

>>2402515
A quick search reveals that the CD40106 is a hex schmitt trigger ic. There are six independent Schmitt-input inverters in the ic— one input, one inverted output.
The CD4093 has four schmitt-input NAND gates. Each logic gate has two inputs and one output.
A search also reveals that a NAND gate can be turned into a simple inverter by shorting its two inputs. You would need another IC. There's also stuff such as voltage rating that you get from the datasheet.

Please help me identify these ICs to reproduce this board.

IC marking: 500P (???)
Board marking: P-1S1905C

>>2402661

looks like a battery protection circuit.
trace it out so we can compare with known reference designs in that space.

>>2402675
>trace it out so we can compare with known reference designs in that space.
I'll give that a shot tonight. It'll be my first time tracing a PCB. I don't mind replacing the IC with an alternative, my goal is for it to perform properly. I am familiar with KiCAD so I think it's realistic for me to accomplish this.

>>2402515
See:
https://en.wikipedia.org/wiki/List_of_7400_series_integrated_circuits
https://en.wikipedia.org/wiki/List_of_4000-series_integrated_circuits
There's a lot of overlap between the two, and also some loan designs like the 74HC4046. And in the 7400 series there's a lot of different logic families, like high-speed CMOS (HC), low-power schottky (LS), etc.

As the other anon said, use the schmitt NANDs in place of the schmitt NOTs.
See:
https://en.wikipedia.org/wiki/Schmitt_trigger
Also if you're curious about your 74LS05s:
https://en.wikipedia.org/wiki/Open_collector

>>2402661
>>2402675
Probably DW01 + dual MOSFET IC
picrel

What college degree or trade school trade would allow me to get a job in electronics repair?

>>2402515
>But you still learn a good deal about the inner workings of computers and digital electronics using simple logic ICs, right?
Well the digital logic is just the 2nd to ground layer, with the ground layer being transistors (and layout if you're autistic). Right above logic ICs is the register layer (assuming you don't count individual latches and flip-flops as a distinct layer), which is much more relevant to how computers function.
If you haven't already, watch all of Ben Eater's videos on the breadboard computer and on communication protocols, they're goldmines in a very educational structure.

>>2402748
>What college degree

job ads will tell you what's needed.
tho they usually go overboard in the requirements.
example: https://resources.workable.com/electronic-technician-job-description

check out videos from this guy (and others) to see if you really wanna do a thankless job like repair: https://www.youtube.com/watch?v=Io6niykPs9s
being a pimp is way easier, more profitable, and you get lots of great perks, like fur hats.

Im a bit confused by the term common mode voltage. The definition is Vcm = (V1+V2)/2 . Isbthis a real measurable voltage? In what way are they common. If V1 = 2 and V2 = 0 the Vcm = 1V, but there is no one volt component on V2. Its just 0V? An amplifier seems to amplyfy this voltage though so i guess it must be somewhere, but i just cant understand where it would come from if V1 is 0V

>>2402829

you know the world is full of electromagnetic noise.
when it lands on a conductor it causes current to flow, and voltages to appear.
when that noise hits both inputs of an op-amp, the op amp shouldnt amplify that signal but reject it.
which it does. data sheets will specify something like 100dB CMRR, common mode rejection ratio.
the higher, the better. and that's all you really need to know on that subject.

>>2402747
>DW01 + dual MOSFET IC
thank you!!

>>2402829
You measure it with respect to something like wall ground, or the other end of a long circuit. Though usually you notice it on the signal itself. Proper grounding and a common-mode choke and caps should render it a non-issue unless you’re doing instrumentation or have a Tesla coil in the same building. Or both, god help you. Differential signalling helps too, same for using optocouplers, when it comes to sending signals over distances.

Tldr: What light dimmer/ Potentiometer should I get?
Hey /diy/, noob here with a noob stupid question. I'm trying to build a hot wire cutter. I bought 26 guage nichrome 80 wire. The length of the cutter is 10". Using this site https://jacobs-online.biz/calc2.html , I need 600 degrees for foam cutting. It says I need 4.6 volts and 2.14 amps, 10 watts. I probably need more juice for cutting hard plastics, not sure what temp but say I try 800 degrees I would need 5.5v 2.6a 14w.
I have a computer power supply to use for power (pic related), I could draw power from a 12V (yellow wire). I guess it draws 14 amps max given the label.
I need a light dimmer/ potentiometer to adjust the heat but idk what kind would work best and be rated for 12v. What dimmer would you recommend?

>>2403143
I recommend a DC-DC buck converter. You hook it up to 12V and then you have a trimmer pot you use to finely adjust the output voltage to something lower than the input.

>>2403155
Thanks for the suggestion. I'm looking into it right now. But it looks as though those buck converter products can't handle over 2 amps, pic related. Seems some can do higher but they cost multiple times more. I found a forum and someone said they used a PWM to control their diy hot wire cutter. So I looked and I found this https://www.amazon.com/PEMENOL-Controller-Adjustable-Regulator-Generator/dp/B07WR4KBMF/ref=mp_s_a_1_4?keywords=12v+pwm&qid=1654764966&sr=8-4
Would this work? It says it's rated current is 5 amps. Not sure if that means input, output or both. Would my psu (14 amp max) kill it or would it just draw (not the max) 5 amps? (Idk how that works)
Do I just have to buy a 12v 5A power supply for it instead?
Also I'm assuming the negative terminal connects to ground since it's not ac right?

>>2403143
>4.6 volts and 2.14 amps
So the resistance is 2.15Ω, subtract maybe 30% for when its cold, so 1.5Ω. At 12V the maximum current will be at most 8A, so any circuit you pick will need to handle 8A instantaneously.
I'd go for a "10A 12V PWM" dimmer. Type those keywords into amazon or aliexpress or ebay and you'll find a dozen listings that will just work. Don't forget an external fuse or breaker if the dimmer doesn't have one.

>>2403155
>a DC-DC buck converter
A cheap DC PWM circuit will work just fine, no need for all the filtration and shit you get with a buck.

>>2403188
>10A 12V PWM
Awesome thanks! I wouldn't have known I needed 10A. I'll go with this one https://www.amazon.com/HiLetgo-12V-40V-Controller-Switch-Module/dp/B00QVONO20/ref=mp_s_a_1_4?crid=1U62ZDO5SL0FF&keywords=10a+12v+pwm&qid=1654766550&sprefix=10a+12v+pwm%2Caps%2C194&sr=8-4
It says it's not reverse polarity protected, but I think I can safely assume Power negative is just hooks to ground.

Hey guys what's the best way to generate a high-ish clock without using a microcontroller? 500KHz to 600KHz would be nice. I don't want to use one of those CMOS based 555s because I would like to learn more
I read about colpitts oscillator but I suppose it would be quite difficult to get oscillating
I am designing a buck converter without a uC and this is just yet another problem to solve in the way

>>2403183
There's beefier units out there like this one:
https://www.amazon.com/XINGYHENG-High-power-Converter-Adjustable-Protection/dp/B08LZ2RWC1/ref=sr_1_117?keywords=buck+converter&qid=1654767585&sprefix=buck+conv%2Caps%2C213&sr=8-117

or the green one here (the red one is a boost):
https://www.amazon.com/Converter-5-40V-1-2-35V-Power-Module/dp/B07SX6XGYT/ref=sr_1_35?keywords=buck%2Bconverter&qid=1654767727&sprefix=buck%2Bconv%2Caps%2C213&sr=8-35&th=1

>>2403188
>A cheap DC PWM circuit will work just fine, no need for all the filtration and shit you get with a buck.
A buck is idiot proof because as you said
>at 12V the maximum current will be at most 8A, so any circuit you pick will need to handle 8A instantaneously
With a buck you're running below 12V so you don't risk your shit exploding.

>>2403194
CD4046's VCO will do it, though it wouldn't be stable by itself. Could use a 555 or similar oscillator to generate a lower frequency clock (desired clock divided by a power of 2) and use digital logic ICs (counters probably, but shift registers or D-flip-flops also work) to make a phase-locked-loop of the desired frequency. Phase-locked-loops are really neat to learn about, so while using a 555+4046 isn't the most practical solution it's definitely an interesting one.

>a buck converter without a uC
Personally I used a comparator, they should be able to get up to a few hundred kHz but I'm not sure if common LM393s will be any better than 555s. If you're doing variable duty cycle then whatever you pick needs to output something akin to a triangle or sawtooth wave, which both the 555 and comparator options do. Not too sure about the 4046, but I think the pin that you put the timing cap on should have a triangle wave on it. Variable duty-cycle is quite an interesting challenge from the point of view of loop stability when it comes to selecting your error amplifier gain (and potential PID characteristics) but it's not the simplest of projects to start with.

If you're doing fixed duty-cycle on-off control (which I'd attempt once if you haven't done so already) then I'd challenge you to try and make the entire converter with a single dual-comparator IC. I've got such a design (constant-current fyi) ready to solder up on this board here, the red one at the top.
Keep in mind that dual comparator ICs usually have open-collector outputs.

>>2403197
Cool Thanks! I'll go with a buck then since it's idiot proof as you said.

>>2403143
>What light dimmer/ Potentiometer should I get?

- use a separate length of nichrome in series to vary the current. use alligator clip to attach at various points. or,
- use a light dimmer to power a 120V to 12V (4A) old school iron transformer.

>>2403143
>What light dimmer/ Potentiometer should I get?

- use a separate length of nichrome in series to vary the current. use alligator clip to attach at various points.
- combine this idea with the fact that you can choose 3V, 5V, or 12V from the supply to give many set points.
- use a light dimmer to power a 120V to 12V (4A) old school iron transformer.

>>2403143
any 2 watt with a bta06 and a couple capacitors and a fixed resistor of say 5 watt across the potentiometer to make it higher wattage . it will technically make it logarithmic . so the max point is actually just before the end of the max turn. but you get better wattage. it also means the slew in output is spread fucked up. so the beginning is most of what you will see different and almost no change until near the end when it starts to go back down. more desirable for audio circuits but a 10 watt potentiometer is like $200

>have martens on roof (probably in insulation)
>make pizza
>*Click*
>fuse blows out
>two fuses, one for water system on balcony, one for inside that oven is connected to
>put both back in
>start oven
>fuse blows again
>only set the oven one, not balcony one
>werks
>hear rumbling again on roof five minutes after
I'm fucked ain't I?

Anyone here make magic tricks? I don't want to spoil the trick, but I saw a trick where the magician used some kind of radio receiver or bluetooth signal to be able to tell which option the audience member picked and it got me really interested in other applications.

I'm colorblind and poor, but I've always been moderately interested in electronics and I think there are some good places to go mixing modern technology and magic.

>>2402853
>>2402959
I know what CMRR is and all that. What im confused about is the mathematical definition. From where is it derived? Common mode voltage is described as being a voltage common to both terminals, but if, as in the example in my previous post, V1 = 2 and V2 = 0 where is the cm voltsge of 1V present on the V2 terminal if it is 0V? Yngdn

>>2403549
>modern technology and magic.

not exactly what you're looking for but check this jewtube channel, and see if you can make some of these
even if you're a horribly damaged human bean: https://www.youtube.com/c/grandillusions/videos

>>2403560
>V1 = 2 and V2 = 0 where is the cm voltsge of 1V present

nowhere.
what you have is a differential input voltage of 2V.
if the op-amp has feedback then it'll try its best to cancel that difference.
if no feedback, or very high gain, it'll fail and act as a comparator.
common mode is a name for spurious or undesirable inputs present on both inputs.
what you have are normal differential input signals, which have no relation to common mode anything.

>>2403575
So where does the definition come from? CM voltage is described as the voltage common to both terminals and it is a voltage beside the differential voltage that is amplified. So it has to be a "real" voltage and not just a mathematical construct.

>>2400805
>I suspect the caps are to help prevent momentary saturation resulting from sudden transients or otherwise high slew-rates. It is a bit strange though.
Is there any benefit in not having them?

>>2403587
You could try with and without, if it’s a circuit board just add the footprint and you have the option whether or not to populate it. I doubt you’d hear a difference, but I’ve been wrong before.

I'm trying to understand what's happening here. The article I read didn't explain how to calculate the cutoff for the low pass.

Ok what's stupider:
>clamping aluminium-backed MOSFET PCB onto bottom inside of aluminium box, then clamping heat-sink onto bottom outside of aluminium box
or
>cutting hole in aluminium box, clamping aluminium-backed MOSFET PCB onto bottom of heat-sink, and sealing around the gap of protruding heat-sink with silicone

>>2403822
Consider DC input, gain ratio is 0 because C1+R2 are a high-pass filter. Consider extremely high frequency AC input, gain ratio is 0 because R1+C2 are a low-pass filter. Consider input such that |X_C| ≈ R, gain is finite. QED, it's a band-pass filter, albeit a pretty low-Q one.

I'm trying to run a 3phase motor. It spins freely when idle. But when I apply power it jumps a bit, then it hums and stays still until the circuit breaker goes off. While it's humming, I can't spin it by hand, the input phases are keeping it still.
Am I single phasing it? Is there a short in the motor? While idle I measured resistance between the different phases and got only 4ohm.

>>2403835
I should add: it's wired delta, and there is another motor running on the same input in parallel and it has no problem. 9 times out of ten it will stall and trip the breaker like I said, but every once in a while it will run for a few minutes before tripping out. Last week it ran for the very first time for about an hour without issue, and now this is happening with no change in wiring.

>>2403822
Calculate the transfer function for something quantitative:
>X_C = 1/(s*C)
>X_bottom = XC2 || R2 = XC2*R2/(XC2+R2) = R2/(1+sR2C2)
>X_top = XC1 + R1 = R1 + 1/sC1
>Vout/Vin = X_bottom / (X_top + X_bottom)
>Vout/Vin = R2/(1+sR2C2) / (R1 + 1/sC1 + R2/(1+sR2C2))
>etc.
>Vout/Vin = sR2C1 / (sR1C1 + R1R2C1C2s^2 + 1 + sR2C2 + sR2C1)
Each term in that equation (except for 1) represents the complex angular speed or frequency "s" multiplied by some effective frequency.

If the resistances and capacitances are all equal (R1=R2=R, C1=C2=C) then you get a simpler equation:
>Vout/Vin = sRC / (3sRC + (sRC)^2 + 1) = 1/(3s + sRC + 1/(sRC))
Here the resulting graph has a somewhat rounded top, a passband gain somewhat below 1 at 0.33 or -9.5dB, and the standard ±20dB/decade rolloff on either side.

More likely though, if you'll be having a substantial flat area in the middle of the band-pass, you can make it such that two values are much larger than two others. Say the passband gain, we want to be as high as possible, so R1 will be very small and R2 will be very large. Then for similar reasons we make C1 much larger than C2. This way we get a simple graph where the passband goes from R1C2 to R2C1, indicating that those two parts in the transfer function refer to the edges of the passband. This is a little easier to see if you express it as:
>Vout/Vin = 1 / (R1/R2 + sR1C2 + 1/(sR2C1) + C2/C1 + 1)
The only terms are either the corner frequencies or simple dimensionless ratios. These ratios are much larger than 1, so we can simplify:
>Vout/Vin = 1 / (sR1C2 + 1/(sR2C1) + 1)
When messing about with transfer functions, you want the terms to actually mean something.

The other extreme would be making R2 and C1 much larger than their counterparts, this gives a triangular peak with a "passband" gain much lower than 1. As seen in the lower equation, the C2/C1 and R1/R2 terms are much larger than 1 and pull down the maximum value:
>Vout/Vin = 1 / (R1/R2 + sR1C2 + 1/(sR2C1) + C2/C1 + 1)

>>2403835
Asynchronous motor running directly on 60/50Hz mains 3-phase?
>While it's humming, I can't spin it by hand, the input phases are keeping it still.
Wouldn't expect that for a dropped phase or two, very odd. The breaker tripping can be expected from a motor stalling, but the immovability you describe is more akin to a stalled DC motor. I'd expect a stalled induction motor to be able to be spun by hand to some extent. And a shorted winding would be more likely to trip the breaker outright or cause noticeable thermal issues.

There's comparable resistances on each of the three windings, I take it? 4Ω is pretty damn low, but since it's an inductive load the actual AC current won't be influenced by that resistance much. And if the resistance is the same that indicates either that it isn't a dropped phase, or that there's a loose wire in there causing it to fail when turned on.
There's no load on it, right?

>>2403837
If it's running on a VFD I could maybe imagine the VFD itself being kinda funky, but you say the same source works fine on another motor so that doesn't explain anything.
>every once in a while it will run for a few minutes before tripping out
It spins just fine? If it is stalling from running on only one phase, it's possible that a strong enough kick to it when stalled could get it to start spinning. That would tell you succinctly that it's not seeing a proper rotating magnetic field, and it's arguably easy to test. Just put a large wrench and breaker bar on the motor and turn it on. Note that this is also a very efficient way to punch a hole through your skull, so maybe try a large pulley with a pullstarter cord on it (the sort that comes loose after unwinding).

The arguable intermittent nature of that fault gives some credence to the suggestion that there's a loose wire causing your issues. Be it a phase becoming detached, or a partial short circuit.

t. never used an induction motor

>>2403201
Anon thanks for the great insight. I think you have sold me on PLLs, I'll try them out (probably not for this project but another one
I think I'll pick up the challenge to do a variable duty cycle one since I have already made an on-off one (in ltspice tho)

)

>>2403846
>I think I'll pick up the challenge to do a variable duty cycle one
Yeah they're a good challenge. If you're doing boost, ensure that you take care of the edge case where 100% duty-cycle means blowing a FET. In practice I think this just means a hard-limit on your duty-cycle. Assuming you're not doing current-mode switching, which has its own challenges at high duty-cycles. Bucks don't have that issue, as for current-mode bucks, they may still have stability issues, not too sure.

As for a project to use PLLs, a pair of CD4046s would make a great FM audio transmitter+receiver pair for IR LEDs. Mono only, but I'd be fine with that. Stereo FM transmission isn't trivial, but it may be possible by using another PLL to generate the subcarrier frequency, and an analog switch to swap between left and right channels, using the same setup (hopefully synchronised by the main wave) to demodulate it.
That's assuming you're not bandwidth limited by the IR LED and photodiode/phototransistor. The issue with them is that you want the maximum possible oscillation frequency in order to make filtering it out of your audio easiest.

>>2396121
Anyone have experience with Car MCU and eeprom programers?

Im looking for a cheapo clone which is best Xprog, Iprog+, Orange5 etc?

Thanks.

>>2403561
Oh man I love that goober!

>>2403934
Sorry anon. I only ever use those at work, so it's all segger and intel stuff, and most of it is designed to be programmed without removing it from the board.

If you can find cables or boards that work with segger stuff, their edu-line isn't too outrageously priced.

https://www.adafruit.com/product/1369

so a gas water heater is not connected to the mains and the power is generated by a thermopole? and what about the igniter, is it just a piezo element? how much voltage does a thermopole generate? i had no idea that you can power circuitry with basically a beefed up thermocouple?? what about the current draw?

>>2403963
>so a gas water heater is not connected to the mains and the power is generated by a thermopole?

I don't think you can say that, as a rule. Every house I've had has had a gas-water-heater (midwestern USA), and they've all been connected to mains I think.

I've never had a problem with them that I could fix though. For me they work until they're old and start leaking, and I then I replace. So basically, I move into a house, the 20+ year old water heater starts leaking in a year or two, and I replace it once.

>>2403981
>midwestern USA
same. I never bother to check until the pilot stopped working: no spark. The old style heaters were easy to fix since the igniter assembly was in a separate chamber, very easy to pull out, clean, and put back in. The newer heaters have these electronic boards (Honeywell) and the pilot assembly is inside the main gas chamber so it has to be tightly sealed and when you remove it, you have to replace the gasket which is a major pain. So I was obviously curious how this thing is powered and I know for sure that the tank is not connected to the mains. I thought there might be a battery inside the Honeywell board but nope. It is self powered by some sort of a thermocouple. Which is mind boggling (to me). Pretty clever if true. You need a thermocouple anyway. So initially there is no power so you push the button on the piezo igniter and it sends high voltage to the probe which lights the pilot and heats up the thermocouple which will then power up the board and it will start flashing. Something like that.

>>2403946
Do you have any books or data on programming ECU's etc? its documentation is quite obscure.

The segger stuff seems interesting but not quite as plug and plug as the eeprom programs on sale on ali.

i dunno if this is a more auto specific question but if you have a car pull handle that is connected to the door frame by a screw that's grounded, how dangerous is it? from the factory the screw is inside a plastic housing, so there is obviously some risk but i want to know what
assuming you are grounded sitting in your car seat it's only dangerous if you're touching a live circuit with it right?

>>2404046
It's totally safe in the electrical sense. Why do you think it would be unsafe?

>>2404054
because the factory had a plastic cover for it? they surely didnt put that there for no reason

>>2404055
Well it's not to prevent shocks if that's what you're thinking.

>>2403838
>>2403827
Thanks for explaining this, but all I want is the equation for the lowpass cutoff as a function of R1, C2, and seemingly also R2, which is the part that puzzles me. I know the equation for the high pass cutoff in this case is 1/(2п(R1+R2)*C1)— no problem there.

>>2404056
what's it for then?

>>2404046
>how dangerous is it?

cars work on 12 volts DC, which is not dangerous at all.
you could eat an entire bowl of 12 volts DC, and you'd be perfectly fine.

>>2404063
a e s t h e t i c s

>>2404066
yeah no that's bullshit, it's to mitigate it from being a ground
i know because i put a test light to battery positive and it didnt light as a ground whereas the one i put in without the plastic did
probably going to just put in rubber washers to be safe but i really dont understand the risk

>>2404067
You're right. It was engineered to electrocute your face while you're driving faster than 65MPH. Haven't you heard the thousands of stories about ChristineAI™? That's why they put chips in cars.

>>2404069
work on your reading comprehension, im saying the factory made sure it wasnt grounded
if you dont want to spoonfeed me why thats the case then that's fine.

>>2404070
If you choose to disbelieve what I told you then that's fine. We are at an impasse.
Check out this pic of my cousin's dog.

>>2404058
Easiest way to get the equation is to find resistance on C2's terminals while treating C1 as a short circuit. When you replace C1 with short and set input to 0V this gives resistance when looking into C2 terminals as R1||R2, which then gives you time constant of C2*R1||R2. Cutoff is then just 1/(2*pi*time constant) = 1/(2*pi*C2*R1||R2). You can only use this approximation when cutoff frequencies are far enough apart (1 decade or more).

any alternatives to veecad with a better UI?

>>2404081
I enjoyed these type of circuits in class. Finding their transfer functions and then generating an equation to punch into matlab.

Help /diy/ I am a bit confused.

I have a 5v regulator that works. It has 3 pins, vin, ground and when I input 3.6v in vin, it outputs 5v in vout. the circuit is picture 1.

In picture 2, I am using a pnp transistor to turn this regulator on and off. If I input 2.4v to base pin the transistor, it connects c to e. and I am using c as ground for my regulator circuit. so if transistor is on, the ground of my old circuit (in picture 1) is now connected real ground of the battery. if transistor is off (2.4v is not connected) then ground is unconnected and regulator/led powers off.

the problem is when I also put an arduino as a load on the regulator (picture 3), the arduino does not turn on. Why is that? It works if I remove the transistor and power the arduino using circuit 1.

I am suspecting that the transistor does not allow enough current to power arduino but I am not sure how to confirm that. If so how can I pick a better transistor?

>>2404136

time to take off your training wheels, kiddo.
https://www.youtube.com/watch?v=35YuILUlfGs

>>2404247
>pnp transistor
shit, I meant npn transistor.

>>2404247

a lil old TO-92 transistor is gonna get burning hot at 200mA.
200mA is also the typical max current for the 'duino.
but when idling, it's less than 50mA, so you should be okay on that end.
however, you committed a capital sin by interrupting the ground.
you never do that coz of ''too many reasons to go into''.
so, redo your shit: switch the 3.6V power line using this circuit.
no only is it the right thing to do, it also means your circuit is gonna get precisely 5V (no transistor losses)
(lower the resistor values by 10x to ensure it works ''real good now'')

>>2404255
I was using npn (not pnp) so it was giving me 3.6V before with a very little loss. check the bottom part of attached pic, the drop on resistor is about 5v, which represents my load

I actually tried your circuit as well but it does not work for me. I am indeed getting 3.6v from that pnp transistor but for some reason the moment I connect my regulator (yellow circle) it stops working, the voltage immediately drops off if I connect vin of my regulator to that 3.6 output of transistor. I need to isolate grounds for some reason I guess

>>2404271
to clear it up: the led that lights up is connected to 3.6v output of pnp transistor, and volt meter shows that it is indeed 3.6. but when I put my modulator there it no longer works. the voltage immediately drops

>>2404271

so what's the thing that's providing 3.6V?
an itsy bitsy LiPo?
does the voltage across the power source sag when you load it?
do you have something stronger, like a 5V power bank?

>>2404276
>so what's the thing that's providing 3.6V?
it is 3 rechargeable ni mh batteries
>does the voltage across the power source sag when you load it?
not sure if I understand, but that 3.6 voltage drops off when I connect the regulator
>do you have something stronger, like a 5V power bank?
my battery works fine If I directly connect 3.6 to regulator, which gives me 5v that can turn on the arduino. but the arduino does not turn on if I also add a transistor

>>2404284
>that 3.6 voltage drops off when I connect the regulator

if you mean the battery voltage drops significantly (sags), then you may have the answer:
the cells are too weak, too old, or not charged enough for the job.
the voltage falls below the regulator's minimum input and it goes on strike.

>my battery works fine If I directly connect 3.6 to regulator

''working fine'' means 2 things, (1) it provides enough volts, and (2) it provides enough amps for the job.
it appears like condition 2 is not being met.

>>2404284
The input voltage to the regulator needs to be 1.5-2V higher than the fixed output voltage (5V). So hook up 7V minimum to the regulator input and try again.

>>2404290
>The input voltage to the regulator needs to be 1.5-2V higher

that's not true.
this is a step-up regulator, not some dinosaur 7805.

>>2404287
>provides enough amps for the job.

what you could do is connect various decreasing resistors across the output of the regulator, to see when the output starts to fall significantly below 5V
this will tell you the exact capability of the cells and the regulator to supply current.

>>2404294
>step-up regulator
part number?

>>2404299

kinda blurry.
i need better glasses

>>2404303
nice

>>2396121
I have an RV. There are six 100w standard mono crystalline solar panels on the roof. These are wired as 2P3S or 2 parallel, each branch having 3 in series.

My current biggest problem is if one panel is in shade (as is often the case) total output is drastically reduced. This same effect also applies to each individual panel.

How can I best optimize power harvest? I understand half cut cells help with this problem. Would wiring in parallel help mitigate one panel drawing down the output of another?

>>2404303
>>2404299
https://www.pololu.com/product/2564
it is this one, yea step up regulator. apparently can even act as step down if slightly over 5.5v but never tried
>>2404297
>>2404287
I will give it a try tomorrow, try different amps for base current and maybe different transistors as well

>>2404332
Other than using fresh batteries as the other Anon said, check that all of your Dupont jumpers are about the same resistance. They're notorious for badly crimped pins.

>>2404343
the batteries are new. here before and after connecting the modulator. before I get 3.7v in collector of pnp transistor. but the moment i connect the modulator, it drops to 380mv

it draws a lot of current (pnp transistor gets really hot) right now because I reduced the resistors. modulator was not able to give 5v with that 10k & 100k resistors.

I think I need to figure out how much amper modulator + arduino draws and use proper resistors and transistors that can supply that

>>2404352
>the moment i connect the modulator, it drops to 380mv

that's very bad news.
see if the same thing happens if you bypass the switching circuit (short the emmitter to the collector) of the PNP.
if so, then it would mean your regulator is probably dead.