/diy/ - Do It Yourself

I want to hook a common use LED strip inside my pc, said led strip has a 4 pin connector. The pins are labeled +12V, WW, CW, +.
Is it possible to connect it to my motherboard or to the PSU? If so, is it possible to reduce the lumens output?
How do I wire it?

>>2001404
I want to put it out that I'm not some RGB faggot, I'm building a pc case from scratch and it involves a satin acrylic front panel, which is the only thing that is getting a slight bling, thats why I'd want the light to be really dim.

Anything to improve or wrong from my MOSFET driver circuit, anons?

>>2001404
You can get a 12v source from the power supply. The black wires are ground, the yellow are +12v.
You'll need an LED strip controller that uses the CW and WW lines to modify any kind of light it puts out. I really doubt your motherboard supports it, you'll need to get a stand-alone controller and put it in the case.

>>2001422
Looks good, only two things to mention.
One, the /SD pin is held to logic high with an internal resistor, so R1 isn't necessary. It doesn't hurt anything, so no big deal.
Two, I'd put a fat tank capacitor near the PV and GND connections to the IRFZ44N's.
Looks good though. What are you driving with it?

>>2001427
>One, the /SD pin is held to logic high with an internal resistor, so R1 isn't necessary. It doesn't hurt anything, so no big deal.
yeah but there is no written value, so I thought I'll add an external resistor just to be sure
>I'd put a fat tank capacitor near the PV and GND connections to the IRFZ44N's.
yea, I am currently updating it and apparently the caps needs to be able to withstand Irms of ~10A so I need a lot of caps
>What are you driving with it?
I got an STM32F411CE board and will be driving it @100kHz as a poor man's MPPT controller. Is 1000 steps duty cycle resolution too many or not enough?

>>2001429
>>2001429
> What are you driving with it?
whoops misread the question, it's for the MPPT project so it's going to drive a buck converter

I have a variac that had a poorly designed volt meter on it. I want to remake it. Have it powered by the primary side and measure the secondary side. The secondary side ranges from around 0Vrms to 155Vrms. I need a circuit design for this but I am not experienced enough in ac or design to do this myself. A general design would be great so I can get started.

Tard question: What would be easier to implement? An 8-channel DAC with 4 stereo headphone amps, or 4 stereo DACs with headphone amp built-in.

Anyone here knows his stuff about power sources?
Im thinking about building my own tube amp that's able to play music through network (RPi, Esp32, or whatever I come up with). I'm not an audiophile, but the tube technology always interested me.
For that, I need two power sources, one ~5-24V for the platine, and one ~250-480V for the amplifier side.
There are a few online sources selling transformers like that, but they're super expensive, and all cost more than 70 bucks.

>The actual question(s)
-Do you know where to get cheap, ready to use multi source power supplies?
-Can I just use two ready-to-use power supplies? I'm a bit sceptical if they would like having their ground on the output side connected

- if that's possible: modern power sources are way more efficient than transformers, but I'm not sure if the chopping frequency will have an effect on my sound. Would that be safe to use

Oh, and if anyone had problems with signal interference, be it power supplies, WiFi boards or grounding, please let me know!

(And pic unrelated, I know that the EL34 are better suited for guitars then HiFi systems)

>>2001454
It depend on your data source to drive the DACs. What are you doing with the 8 channels? Is the audio 8-channel, or do you have 4 sets of 2-channel audio data?
An 8-channel DAC would be easier if your data is already encoded into 8-channels in one file that you can buffer into the DAC. If you have multiple files that each only have a couple channels of data, the separate DACs would be easier.
More info needed i guess.

>>2001471
The audio will come from a DSP, so it'll be 8 channels I guess.
DSP will probably be a adau1701 because cheap and easy to use.

Ok guys, i need help.

What amplifier are 3 and 4?

I thought that 3=inverting but the circuit looks like non inverting same thing with 4.

>>2001587
It's do your own homework.

>>2001587
Think about it like this,
the op amp tries to make Vp and Vn equal to each other. This is called a "virtual short".
The only way it can accomplish this is by going high or low on the output, with high and low being what the Vcc and Vee voltages are.
For each node, write out the KCL equations then use the fact that Vp=Vn to figure out the exact voltages.

>>2001588
Are you retarded?

What has "I don't know what amplifier type this is" to do with homework?
I don't ask what the gain or the ressistor value are.
I bet you know every circuit every existed.

>>2001598
Not him, but that is definitely a homework tier question.
Now maybe not actually *your* homework, but it's something you can and should figure out yourself.

>>2001589
Never heard of virtual short only virtual ground.
Thanks you for the tipps to solve this equation but like i said, i don't need a equation etc, only the name, is it a non inverting amplifier, inverting amplifier or something else.
I want to look on a circuit and see instantly yeah thats an (non) inverting amplifier or not.
Maybe this circuit is in a good formulary but mine kinda sucks.

>>2001604
I don't know what school or university you went, but over here i get 0 points from 5 if i answer,if circuit 2 is an inverting amplifier with yes or no.
They want to know why and a derivation. So i don't know how a yes or no answer can be a homework?

in designing audio circuits, what is the root cause of mains hum? Originally I thought it was the boards acting as antennas but apparently not.
How do you design an audio circuit that's robust against mains hum and external noise?

>>2001648
By wrapping all the audio parts of the circuitry in a grounded metal box and keeping the PSU well filtered

So I finally got myself a wire crimper since I don't want my wires to slip out of terminals. Problem is, after looking into it, it appears that my ferrule colors are abso-fucking-lutely not adherent to the color standards they should be, or at least not any I can find. To add to the confusion, pic related says 0.5mm^2 wires should be put in the white ferrule, and the box says that white ferrules should be used with 22AWG, but the charts I've found say that 20AWG is 0.518mm^2 and 22AWG is 0.326mm^2, which is definitely undersized for that.

What do? I've got 18AWG and 20AWG wires I need to crimp and no fucking idea what size ferrule I should be using for them.

>>2001648
Mains hum comes from ripple on the power rails which finds its way into the output. The power supply needs to be well filtered and the amplifier also needs to be designed to reject power supply noise. A good book on this topic is Audio Power Amplifier Design by Douglas Self.

>>2001587
non-inverting and inverting schmitt triggers

simulate them and see how they work with a high-amplitude wave going into them

>>2001589
this is incorrect in this instance, because it only applies to negative feedback.

>>2001435
>I need a circuit

digital or analog? analog is super simple, and way cooler than digital, which are composed of satanic symbols imposed on us by the arabs.

>>2001435
>I need a circuit

digital or analog? analog is super simple, and way cooler than digital, which are composed of satanic symbols imposed on us by the arabs.

>>2001670
>no fucking idea what size ferrule I should be using for them.

wow, such helplessness.
use simple common sense: use the ferrule that makes the tightest fit without forcing it.

>>2001468
>Can I just use two ready-to-use power supplies? I'm a bit sceptical

dont be skeptical. this is a common practice without any inherent problems other than size/weight.

>get cheap, ready to use multi source power supplies?

one way to get a cheap high-voltage transformer is to use ''travel transformers'' which are relatively cheap, esp if you get the low power ones, like 50W. they're usu 120:240V so you can use one to double your line voltage, to get 240 from 120, or 480 from 240.

>>2001686
Wow thank anon, even more than i ask for.
Do you have a recommendation for a good formulary?
My formulary kinda sucks, it doesn't even have the circuit symbol.

>>2001727
>formulary
what the fuck is that

just learn about negative and positive feedback, all 4 of those circuits are implementations of those principles

Any cheap soldering iron that won't melt it's own tips?
Those cheap aliexpress ones are worthless, even on the lowest temperature setting the tip will survive 1-2 sessions with cleaning and all.

>>2001736
T12 stations, TS or pinecil if you want something portable.

>>2001736
>inb4 you use steel wool or sandpaper to clean tips

>>2001750
Thank you, I will need to think about that, soldering station seems very nice, but I move between 2 places every week or two, and I am not sure if I have enough free space in my suitcase to carry it with me.
>>2001755
I use a moistened sponge and colophony, never sanded a tip, and I do not have steel wool. I suspect something is wrong with temp control, since even at lowest temp (200 celsius on knob, but I think that's bullshit) the tip and the mounting element is getting burnt.

>>2001733
>formulary
We call it formulary, maybe in USA you call it reference book / handbook

>>2001736

my Weller WP-25 which is over 20 years old and works as good as new. tips cost $5 and last 5 years.

>>2001693
Thanks for the response I had an analog but ended up breaking it when I was learning how it was constructed so bought a digital but it was constructed in such a way the measurement would never be accurate. I want to go digital kind of interested in driving lcd. But need a overall circuit first.

>>2001736
Just save your money and get a 100 dollar weller or hakko station or something. You'll end up saving more money in the long run and have flexibility on what you can work with.

>>2001766
>moistened sponge
The thermal shock from touching something wet is probably not ideal for a tip, despite how common it is. I swear by copper wool, a quick wipe with a dry facial tissue also cleans somewhat well.

Post iron/station. While they technically do have temperature negative feedback controlled by a dial, the analog soldering irons have a rather rudimentary circuit within, the cheapest digital soldering iron would be a good step up. While I never had any issues with my analog temp controlled iron for the couple of years I had it, you may have just gotten a bad one.

>>2001879
Yeah, I am realising that now, I don't plan to solder that much and it's all THT on perfboards, but those cheap pieces of shit can't even deal with suck a basic job.
>>2001880
>Post iron/station
Pic related is my "soldering iron", it's the cheapest kind from aliexpress.
Tried to solder a DIP-40 socket to perfboard today, starting with brand new fresh tip. As soon as iron got hot i tinned it and started soldering. After 8 holes the solder wouldn't stick anymore. Tried cleaning it with colophony and wet sponge. I wasn't able to make the solder stick anymore, so I decided to start with another new tip.
Also I noticed than my colophony is past its expiration date, i don't think it would be of any issue but I tried that another tip without using colophony at all, only sponge. Same thing, I could wipe the tip to see the silver surface but solder still wouldn't stick. I have also another tip which literally melted and bended itself during soldering. You can see the tips in the pic, the tips have turned black and the rest of them have turned to light blue.
It's either a complete garbage, or I am a retard who is doing something wrong.

>>2001940
>colophony
Are you using straight pine pitch or rosin flux? Mix a small amount of isopropyl alcohol with your "colophony" and try again. Because your iron doesn't have temp control, plug it into a dimmer switch so you can dial in the temp without lifting the plated through-holes on the perfboard.

>>2001949
>Are you using straight pine pitch or rosin flux? Mix a small amount of isopropyl alcohol with your "colophony" and try again.
Yeah, it's the solid kind that you are supposed to make a 25%/75% solution with isopropyl alcohol, but I just use it to dip the tip of the iron to clean it. I have flux which I apply on the solder pads before soldering.
>Because your iron doesn't have temp control
It does, you can see a small trimmer on the right of the handle in the picture, I have it set to the lowest value (200 celsius), but the tip still becomes unusable after ~5 minutes, no amount of cleaning will make the solder stick to it on all the surface, just on some spots if I am lucky.

>>2001940
Yeah those irons aren’t too bad, sounds like you got a dud. You could take it apart and see if it’s got any burnt or poorly soldered parts, though it’s not like you could fix them without another iron.

If it’s shiny but no solder is adhering to it, that’s a rather unusual situation, and makes it sound like your iron is too cold. If you quickly dip the tip in rosin, is the rosin smoking off after 10-100 seconds?

>>2001949
It should have temperature control though, that dial on the handle goes to a dual op-amp circuit which somehow switches mains to the element with feedback via a thermocouple or thermistor in the tip. Though it might not be working at the moment. Real neat circuit either way.

>>2001965
>you can see a small trimmer on the right of the handle in the picture
I'm blind & stupid. Apologies. Maybe the pot is bad (max heat)? Or the tips could just be shit. Chinks suck at metallurgy.

>>2001970
Yes, my mistake.

>>2001970
>You could take it apart and see if it’s got any burnt or poorly soldered parts, though it’s not like you could fix them without another iron.
True, will check it out tomorrow.
>If it’s shiny but no solder is adhering to it, that’s a rather unusual situation, and makes it sound like your iron is too cold.
It's not really that shiny, i can see the silver surface, but it's mostly covered in black. I tried cleaning it really aggressively with the sponge but can't get all of the black stuff out. Also increasing the temperature makes the tip blacken even faster.
>If you quickly dip the tip in rosin, is the rosin smoking off after 10-100 seconds?
Smokes off instantly, also the tip will burn the pads on perfboard and make them get peeled off if held it for too long, but still the solder won't stick.
>>2001972
>Maybe the pot is bad (max heat)?
There's an LED inside the grip and it's intensity is tied to the temperature I set on the pot, so i suppose the pot is working. Still Chang could put a wrong value, or something else on the board is wrong/broken/missing.
>Or the tips could just be shit. Chinks suck at metallurgy.
Looking at Aliexpress they are ridiculously cheap, like 1.5 euro per 5 tips, so they must be shit, question is what is shitter, the iron or the tips.

>>2001374
>>1995422
I currently have one of these analog meters on my laser cutter, I would like to swap it, or add to it a digital meter with at least 2 decimal points so I can read it more accurately for reproducible effects.

It has a single knob to control current and I just want a readout of what that current is exactly that the analog meter is running, a percentage, or whatever, just something that is actually a number I can set it to, to get the same strength on the next project.

any advice would be appreciated

>>2002017
Buy a DC current panel-meter on eBay for $5. There are ones with various current ratings, and a variety of input voltage ranges, there should be one that suits this application. But IIRC laser cutters can use pretty high voltages, so make sure it’s on the low-side with respect to your power rails. Unless it’s got a hall-effect current sensor that is.

You can buy your own Hall effect current sensors btw, Andreas Speiss reviewed a few. But that would require a current sensor, an ADC, a MCU, and a 7-segment display, and also the code to read the sensor and multiplex the display.

>>2001994
>but still the solder won't stick
You aren't using lead-free solder, right?

>>2002027
Nope, 60/40 solder, when the tips work they work well, soldering is easy, when the tips don't work it's almost impossible.

>>2001736
Not to shill (((amazon))), but their $16 60w iron ("best seller" or something) is solid. Three years and counting

>>2002031
Strange. It's probably best to buy another iron, even another cheap one. Fuck that frustration.

>>2002038
Actually it's my second iron, I got my first cheap one a long ago, and it was even worse. First time it came broken, because the cable was not attached to grip at all, the only thing that it was attached by were the tiny soldered wires inside, which broke when you pulled the cable slightly. After repair i wrapped the whole damn thing in tape so the cable wouldn't move. What a piece of shit.
I'm considering buying something more expensive like those KSGER T12 or TS100, but I see people on forums having problems with those too, ending up with broken stations/irons.
I just want to solder some THT for gods sake.
>>2001782
>>2002032
Will take a look at those, thanks.

>>2001766
>I move between 2 places every week or two
Then a Pinecil or TS80P should be good. T12 station itself isn't very large (I have one), if you're needing a seperate power brick with the above irons it's going to take up less room. Also is cheaper. But if you already use a 24V (or 19V, 2/3 power tho) power brick for a laptop, then the Pinecil and TS80P portable DC irons should be good. TS100 might also be a match if your power brick doesn't fit the other two.

If you really need something portable without a DC brick, then the digital version of what you currently own is reasonable. Search "temperature controlled iron" on alibay and it should be noticable, it has a small screen and two buttons on the handle instead of a knob, and plugs directly into the wall.

>>2001994
>I tried cleaning it really aggressively with the sponge but can't get all of the black stuff out
That's unusual, try rubbing with a dry tissue.
>Smokes off instantly
>burn the pads on perfboard
Yep, you're definitely too hot. So hot that the flux can't last long enough to make a join once the workpiece is up to temp. Surprised the element hasn't burnt out. Like the other anon suggested, running it with a dimmer and using it as a dumb iron without temperature control isn't out of the question in a pinch, though I'd order a new iron/station asap regardless.
>question is what is shitter, the iron or the tips
The tips are shitty sounding, but I think your iron is shittier.

>>2002046
99% of T12s and TS100s and TS80Ps and such won't be broken out of the box. For your current iron it's probably 90-95%, by nature of them running directly off mains. Haven't heard from anyone with a Pinecil though, they're pretty new, but IIRC they're intended to be better than the TS100. Open-source hardware too.

>>2002046
>I just want to solder some THT for gods sake.
Get the Amazon iron to get going. You can return it if broken and you won't have to wait forever to get it. Then you can decide on an upgrade like Hakko or Weller in the future. Avoid the chinkshit because you're going to buy it 10 times and spend more in the long run.

>>2002017
>>2002026
https://www.ebay.com/itm/50mA-LED-Digital-Ammeter-DC-0-50mA-Analog-Amp-Panel-Meter-Current-for-Engraver/124297548836?hash=item1cf0b61424:g:M18AAOSw63ZfNWOp
This is the closest thing I have found so far, just about all of them I've found were in the amp and not miliamp range.

Given the name of the listing, I assume this is what I'm looking for?

>>2002087
>This is the closest thing I have found so far, just about all of them I've found were in the amp and not miliamp range
Oh, so you have a <1A laser? Is it a CO2 tube that makes up for it with high voltage? Looks correct in that case. There's also the option of taking a 1A model and replacing the current sense resistor with 10 times the resistance.
It requires a 5V input, I guess you have one spare? It doesn't look to have a hall-sensor, so definitely connect it on the low side.

Also are you varying the power with a potentiometer? Not gonna get much better than ~2% variance with a pot, I'd consider seeing if you can replace that part of the circuit with something digital, with a rotary encoder and feedback from a current sensor.

any one have a analog circuit that can tell the difference between sin and triangle? this is a sort of side project im thinking up. the idea is analog rc

the thing is the easy way to do it is to make 1 op amp oscillator to do square and have another op amp as the mirror to read it so you dont null your multi vibrator and just use multiple caps for part of the frequency adjustment and instead of jumpers its momentaries and a potentiometer to give more frequency adjustment. but you end up with a antena for each thing times 2. so 1 motor needs 2 antenas and if you got room for 4 antenas wouldnt it be nice to have 1 big one instead of 4 smaller ones?

so what i came up with is triangle is a fuck and cant get it up in the bed room so 1 zener makes it look like it isnt invited to the party except for a brief instant at its peak and square is always getting through. the brief instant it gets through it needs to cut on a bjt but rise time and amount of current can make that almost nonexistent when you consider a resistor on the back end of the bjt. in real time the flutter may not even manifest observably without a osciliscope and on a rc anything not important.

so thats differentiating between traingle and square but sin and triangle seems to similar and so far thats only 2 for each single frequency used. better than 4 for a rc car or boat but its still cumbersome. worst case i do it that way and if i have to do it that way i use resonante frequency boost through a inductor and voltage divider with a couple Mohm to know the difference between any signal and the inductors resonate frequency signal to make it look fancier. nothing says i know my shit like a spark gap on a rc car that feeds a neon lamp as a voltage regulator and doesnt fry a dc motor

any one know a way to have a circuit tell the difference between the 2?

>>2002110
Probably a comparator, compare a sine with a tri/sin and rectify the output?

>>2002093
I'ts a 40W co2 tube laser yah

And yah I'm using a potentometer, honestly I'm not looking for hyper accurate variance or anything, it's just that I'm mainly doing image rasterings and I want to do a shit load of examples to really knock down what the "best" (in my view) amperage is for what I'm wanting, and being able to turn it back to that amperage after I'm done cutting.

tl;dr My main focus is reproducibility more than accuracy, the number can honestly be 100% wrong as long as it's consistently wrong.

>>2001994
Try this stuff -
https://www.ebay.com/itm/141716446469

Lads, help me out.
So I have this U-229 to kenwood connector (basically from radio to headset: microphone, speaker, push-to-talk). After I opened I noticed something weird. I have to this day connected all the pins to correct places with few resistors if needed but Ground and Microphone ends hand some weird things going on.
Might this be a amplifier circuit or some audio quality circuit or what is going on?
Can capacitor microphones even be amplified without external power? I imagine the sound quality would suffer.
I made a shitty picture of the circuit cause the whole thing was covered with hot snot. I'm 95% sure it was wired like this.

Added the npn symbol but might be wrong. I'm retarded with electronics.

>>2002179
That doesn't look like a BJT amplifier topology I'm familiar with, the resistor from input to output is throwing me off. Could maybe be a unity-gain buffer amplifier. Could maybe also be something with a JFET though.

Why the hell is the gate-source cut-off voltage of JFETs so unpredictable? I designed a voltage controlled amplifier using a J113. I'm building a lot of them and about 75% of the time it doesn't work because the transistor's cut off is so far away from the one I used while prototyping. It can be anywhere from -0.5v to -3.0v. I ordered them all at the same time from Digikey.

I've looked at every JFET on Digikey and none of them keep the cut-off voltage to within a narrow range. How does anyone design circuits with these things when they're so unpredictable?

>>2001940
Mine is even worse but I can still use it, not pleasant though.
Just have to clean the tip a lot.

>>2001768
>>2001727
stop mistranslating things stupid br.

>>2002110
Notch filter around the sine frequency and a low pass filter to limit the bandwidth at idk, the 10th harmonic. If the filter output is close to zero then you either have nothing in the output or a pure sine wave, if it crosses a certain treshold it means other shit passed through

>>2002241

>>2002241
this is simply not true

>>2002217
JFET tester, sounds tedious tho

>>2001473
>adau1701
That is still only 4 output channels from a single stereo input.
Assuming you want to use 2 of them, you'll have 8 channels output total. The adau1701 outputs are already analog, so you would go from it to an amplifier.
What are you making? Do you just want a lot of speakers with individual controls, or are you making some headphone surround sound system?

>>2002059
>Then a Pinecil or TS80P should be good. T12 station itself isn't very large (I have one), if you're needing a seperate power brick with the above irons it's going to take up less room.
I noticed from reviews on ali that T12 comes just wrapped in bubblewrap, it does not have a nice box to put it into, so I would need to be careful when packing it for travel. TS80P or Pinecil looks nice since they are small and I could just put them in the boxes they came with.
>Haven't heard from anyone with a Pinecil though, they're pretty new, but IIRC they're intended to be better than the TS100. Open-source hardware too.
Shame that Pinecil is sold out at the moment.
>If you really need something portable without a DC brick, then the digital version of what you currently own is reasonable.
I could try that, but I'm worried that I will end up with 3rd useless soldering iron, since it looks identical to the one I have now aside from being digital.
>That's unusual, try rubbing with a dry tissue.
No luck, some of it will come off, but most of it won't.
>Like the other anon suggested, running it with a dimmer and using it as a dumb iron without temperature control isn't out of the question in a pinch, though I'd order a new iron/station asap regardless.
Yeah, I need to make up my mind and pick something up, I am stuck in breadboard hell and really need to transfer some of my projects to perfboard.
>>2002061
>Get the Amazon iron to get going.
All I can see on Amazon is the same kind they sell on ali, but with higher markup.
>>2002224
>Mine is even worse but I can still use it
Well, I can't really use mine, couldn't even finish soldering DIP-40 socket to perfboard.

Also I disassembled my piece of shit, but nothing looks burnt or anything. They only weird thing I could notice is E28 resistor (the calculators say 1.3Mohm?), but the markings say 82K. Don't know if it is just lack of consistency, or an error.

>>2001648
As the other anons said, the power supply needs to be filtered well. Building a PSU is a job in itself if you are looking for high quality.
The amp layout in the enclosure also effects signal. If you have the mains voltage coming into the enclosure, and the mains wire running across the case to a power switch, then back across to the transformer, you have those wires carrying high voltage all across your box. They should be short and kept away from the audio circuitry. I like to divide an enclosure up and shield the sections from each other to help minimize signal leakage.
Grounding can also be your friend if done correctly, but can also the the cause of some nasty hum if done incorrectly.

>>2002046
I picked up a Hakko FX-888D a couple years ago and never looked back. Its been fucking amazing. I'm still on my first tip that came with it, and I've going through nearly 10lbs of solder. I use it for tht, smd, and general rework with zero problems.

>>2002281
Those are analog channels, the thing has ADCs and DACs built in, but apparently you can wire a lot of digital I/Os to it (through TDM).
I'm not really "making" anything, just seeing how I'd go about creating a digital crossover for multi-driver headphones.
Right now the idea is USB interface - DSP - 8ch DAC+HPA.

>>2002288
>Hakko FX-888D
Lmao, the colors remind me of that Hot Wheels PC.
Seems nice, but it's out of my budget, I am not willing to spend that much on an iron, I don't do smd, I just need something that will get the job done for basic tht.

>>2002299
The 936D is cheap and pretty good.

>>2002299
If you want quality you can always use those T12 stations with Hakko tips.
Though most people seem to do fine with clone tips.
I wouldn't use anything without cartridge tips these days.

>>2002282
Mine

>>2002302
Nice, will add it to the list.
>>2002308
Good point, with T12 I could get some genuine tips if the chinese ones won't do the job, with TS100 and similar I'm probably stuck with chinese tips.
>>2002312
Damn, at least it still works.

>>1997242
Check the charging port for obstructions and bad solder joints.

>>2002217
You could use JFETs with feedback. Either directly with an op-amp to the one JFET you're using for the VCO, or if that isn't possible, with a matched pair and phantom feedback or whatever it's called. Though if you're going to the effort of matching your JFETs, you might as well just choose surrounding components based off what you measure. Matched pair use is only really warranted if there's a lot of drift.

>>2002241
This should work, but only if the sine is of a constant frequency. A slightly more versatile use is to use a high-pass filter that's steeper than the F/3, F/5, etc. frequency cutoff of a triangle wave (I think 2-pole is required, maybe 3), then compare that amplitude to the amplitude of the input signal. I think with some log amps you can get something that gives the same response regardless of frequency or input amplitude, so long as you're above the noise floor and below the filter's corner frequency.

>>2002282
The T12 is in a solid aluminium case (if you get the aluminium version), and the cable and pencil have good strain relief on them, I'd say they're fine for travelling with.
>picrel
That looks a lot simpler than the one I have. Unless there's some SMT ICs on the other side, it might be a simple TRIAC-based circuit without feedback. How many wires are coming from the element/tip? If it's only 2, then there's almost certainly no temperature feedback.

>>2002560
>The T12 is in a solid aluminium case (if you get the aluminium version), and the cable and pencil have good strain relief on them, I'd say they're fine for travelling with.
Nice, I think I will pick T12, TS100/Pinecil looks flimsy, the tips are harder to get and I would need to find myself some flexible power cord and power supply, I bet none of my laptop ones would fit.
>That looks a lot simpler than the one I have. Unless there's some SMT ICs on the other side, it might be a simple TRIAC-based circuit without feedback. How many wires are coming from the element/tip? If it's only 2, then there's almost certainly no temperature feedback.
Yes, there is nothing on the other side, and only 2 wires are coming into the tip. For the meanwhile I can try to control it with extension cord with power switch when I go back to my family house, don't have one on hand and I don't want to get myself more frustrated with this iron.

Soldering noob here.

I just made my own aux cables, but in the process my fingers, which have been in contact with soldering lead, have touched the cable sleeve and the connectors.

If there is no visible residue, is it safe to use these or will I get into contact with lead? Or can I clean them somehow? Need to be extra careful as my wife is prego and will be using my cables

Can I rewind a MOT to output low voltage high current for battery charging/car starting?

Can somebody brief me on led acid charging? Can I just put a lightbulb in series and charge it to a voltage set by a comparator?

>>2002604
Just wipe them down with a damp rag if you're worried.

>>2002609
>Can I rewind a MOT to output low voltage high current for battery charging/car starting?
Yes.
>Can somebody brief me on led acid charging? Can I just put a lightbulb in series and charge it to a voltage set by a comparator?
They're not as finnicky as lithium ions at the least. There should be documentation online as to their charging curves.

>>2002604
Lead poisoning is accumulative unless you ingest it or superheat it and breathe particles into your lungs, but I would clean them anyway out of precaution for your babby. Wash your hand after soldering, too.

>>2002613
*hands
lmao

>>2002609

search youtube for ''4 New Ideas using Microwave Transformer''
advance to 17m mark.

>>2002611
>>2002613
Thanks, I'll wipe it off with a damp rag then

Hi, I've designed a PCB that controls two valves. The PCB takes 12V and also has a USB port for serial comms that I plug my laptop into. When I connect the board to my laptop when the board is getting 12V DC it turns my laptop off. When I connect the board to my laptop when the board is not getting 12V the board will turn on and the serial comms will work fine (but of course the 12V valves will not function). What is going on here? I'm pretty new to electronics and PCB design, so sorry for the amatuerish question. Any insight appreciated. Thanks.

>>2002680

And here is the PCB

>>2002680
>>2002682
I can't see your schematic. Did you isolate the 12V side from the 5V?

>>2002694

hopefully this pic is better.

The 12V is just coming in from the DC jack into the 5V regulator

>>2002750
It's also of course goes into the DPDT relays (in the "Valve Relays" block section)

>>2002750
>>2002751
Try cutting the Vcc trace (or use a spare USB cable with 5V disconnected) from the USB connector on the board since it's being powered by the 5V regulator fed by your 12V PSU. Leave the GND trace connected.
Check the inside of the USB connector and plug for shorts too.

>>2002755
okay thanks boss, I'll try that now

>>2002755
It worked!!, thanks again man. Really appreciate it.

>>2002768
Noice.

>>2001736
The pinecil is the one to get right now.
Basically a better ts100 at a fraction of the price.
See https://hackaday.com/2021/01/05/review-pine64-pinecil-soldering-iron/

>>2002784
It looks nice, but I need something now, and according to pine64 they won't be available until at least february.

>>2002789
Sucks to be you. I got mine in December. A friend of mine ordered his last week.
If you need something $now, your best bet is to go to a local store and get the cheapest random basic firestick-style iron as a stopgap.

>>2002784
Yeah wtf this seems too good to be true
Is it great or just good?
Is there a catch that I'm not seeing?

>>2002803
There's no catch.
What's clear and explicit, however, is that the launch price is discounted, in order to promote the product.
Price can and will definitely go up.

>>2002806
Well shit, guess I'll be refreshing the store page for the next few weeks...

Is it possible to implement Qualcomm quick-charge 3.0 as a DIY?

>>2002810
Sure. You probably won't get the same energy efficiency, but it's definitely possible to DIY a quick charger.

>>2002768
In future, put a diode in series with the USB 5V input. That way 5V can never flow back into the laptop.

>>2002810
You can bitbang literally any protocol with an MCU and probably some supporting circuitry. Heck, you could even bitbang a protocol as complex as USB using discrete logic hardware, but it would probably cost you a few hundred dollars and cover a dozen PCBs.
Whether or not it’s worth doing is another thing entirely. I’d look for a dedicated IC for it on LCSC or wherever and just use that.

>>2002827
Oh, unless it has literally no handshake whatsoever and is just a higher current PSU with no feedback. Which sounds pretty shit.

>>2002827
>>2002823
I have a simple 8 bit li-ion project. I guess I would need a Qualcomm enabled device to use quick charge and this would be very complicated.

>>2002810
>>2002839
You’re talking about the downstream device that needs the juice? For a few bucks each on eBay, there are ‘trigger’ boards for USB PD. Not sure if the same this exists for the Qualcomm protocol, if thats a hard requirement.

>>2002810
google for "QC3.0 decoy" for input or "QC3.0 buck" for output

>>2001374
suggestion for next OP - archive of all Popular Electronics issues from 1954 to 2003
https://worldradiohistory.com/Popular-Electronics-Guide.htm
>Popular Electronics was created in 1954 by Ziff-Davis for an audience of electronics hobbyists and experimenters. It soon became the "World's Largest-Selling Electronics Magazine"
>The final issue was January, 2003.

some pretty neat ideas if you flip through random issues

>>2002955
Oh neat, I've added it to my personal paste (OP for this thread and some previous ones). It's half advertisements and out-of-date technological musings, and probably takes up a few TB since it's all image files, but it's a decent bulk resource anyhow. He has a searchable (ctrl-F-able) index for all issues linked to your page, which should help a bunch. Actually all the issues are searchable themselves too. Neat.

There's quite a lot of data out there for this hobby, so maybe there should be a denser wiki or document or infographic with a lot of links on it. Especially appnotes. Ideally something searchable by topic.

What are some decent resources for audio circuit design? Both digital and analog side.

>>2001426
So I should be able to get a SATA3 to molex connector and wire it to the +12v and ground connectors right?
Do i need a controller even if I dont want to be able to change the light intensity?

>>2002968
what specifically? synfezisers, or high-fi stereo outputs, or DSP, sound design...?

>>2002975
>Do i need a controller even if I dont want to be able to change the light intensity?
Assuming the WW and CW wires are the two negatives (no clue what "+" means if it's different to "12V"), then you could just put resistors from the two negatives to the 0V rail. Depending on the value of those resistors, the brightness of the two channels would be set at a certain level, setting the colour. But if it's a 10W LED strip, you may need resistors rated as high as 5W, which are a little big. They'll also get hot. And be a bit of a waste of power.

A proper controller would have two MOSFETs doing PWM instead of resistors. You can make your own 3-channel PWM driver with a single quad-comparator IC (e.g. LM339) and a bunch of passives plus the MOSFETs, if you're wanting to go that way. You could buy a little LED strip controller, probably smaller and cheaper than anything you could make, more convenient too, though the remote control solution can be a bit shit and they rely on internal non-volatile memory.

>So I should be able to get a SATA3 to molex connector and wire it to the +12v and ground connectors right?
Any unused connector on the mobo (or psu) that has 12V on it will be fine, so long as you're careful not to have anything that could short out and smoke your pc:
>molex to sata, lose all your data

>>2002976
DAC & headphone amp design. Maybe some DSP too.

What type of potentiometer is this?

>>2002986
regular one?

>>2002986
a reversible one? assuming those are switches and they're both just a single dpdt
there's fringe uses for such a circuit, i guess

>>2001736
Okay, I ordered KSGER T12, hope it arrives in one piece.

Anyone know how easy it is to reuse the usb connector from a usb c to aux adapter cable thing? I want to reuse it in my own, longer cable. Can I just cut off the female aux connector and expect to see the three usual stereo cable wires I can work with or does the usb part of it complicate matters?

>>2003008
Good luck! What tips are you getting for it? I like the K that came with mine for coarse stuff, but for finer stuff (SMTs) I use a D12. I hope you ordered the thin blue handle with the black rubber grip, the wider one isn't as good.

>>2003010
>Can I just cut off the female aux connector and expect to see the three usual stereo cable wires
Probably. I suspect all the circuitry is in the USB end. But often the wires in these things (speaking from earphone repair experience) aren't easy to solder to. They're some sort of litz wire I think, lots of really thin enamel insulated strands loosely twisted together, the insulation takes a while to burn off. There's also often strands of nylon or something inside them for strength, which you have to seperate and cut out since it also messes with solderability. I'd give it a miss to be honest, unless you've got a couple spare.

>>2003013
>Good luck!
Thanks!
>What tips are you getting for it? I like the K that came with mine for coarse stuff, but for finer stuff (SMTs) I use a D12.
I got the set with K, ILS, BC2 and D24 tips, will see how they perform and buy some other ones when needed.
>I hope you ordered the thin blue handle with the black rubber grip, the wider one isn't as good.
I bought the black one, read that some people had issues with the blue one with rotating cables and tips.
If the station works fine I will be happy to buy other handles for it and check them out, I don't expect to change tips on the fly for now, but if I do then it would be a chore with the handle i got.

>>2003010
If you want to do it neatly you can expect this on the USB end.

Would adding a magnet to a metal detector such as in the center of the coil help?

Since it detects changing fields not static ones. And the magnet moves with the coil it should be static, but the magnet would be able to help induce a field in metal it passes over and help it be picked up by the coil by making and overall stronger induced field yes?

>>2002299
Yeah, the colors could have been better than "babbys first iron" but I could care less about looks so long as it works.

>>2003034
Hakko makes high-quality stuff that works well for years. Good choice.

>>2002985
https://sound-au.com/
Not really a lot of DSP, but there is a LOT of good info and projects about audio here. I've been building amps for nearly 20 years and I still reference his site.

If I design a PCB with two copper areas on top and bottom layer, will I have to worry about the parasitic capacitance between these areas?

>>2003084
As long as your ground planes are connected with plenty of vias you should be fine, sans RF and HV circuits which require additional isolation and specific board layout.

>>2003087
I see, if they are connected with plenty of vias so I don't have to worry about them. Is it because the electrons won't build up if there is no bottleneck between these two planes?

>>2003090
Yes, because the ground reference is shared there is no difference in potential between each side of the board.

>>2003093
Ok, thanks for the explanation. Here's a tortured loli pic for you as my gratitude.

>>2003096
lmao okay
thanks?

I want to like analog computers, but they just sound so damn tedious

>>2003184
You don't like abacus because you're raycis against chinks, nigger.

>>2002772
>>2002827

Thanks for the diode tip.

Unfortunately the serial port isn't enumerating on my linux machine. I've talked with this board in the past via minicom. It uses an ftdi chip as shown in >>2002750

Any idea as to why it's not being detected?

Is there a way to fasten paracord properly at the ends when used as cable sleeving when there isn't a type of clamping mechanism available?

>>2003216
Does the board respond to another machine?

>>2003245
no it does not. I've gotten it to respond briefly since cutting the 5V USB line. I briefly connected 5V from the regulator to the USB and then disconnected the wire I was using before plugging anything back into my computer. I noticed that the LCD module went blank (backlight still on, only dimmer). I plugged the board into my computer and it enumerated. I took it out, plugged it back in again and nothing. I pressed my finger against the voltage regulator to see if it was hot and the LCD lit up again... I'm trying to look for bad connections to resolder, but perhaps I'm missing something more fundamental here?

>>2003251
>>2003251
https://electronics.stackexchange.com/questions/393066/how-to-control-12v-from-5v-using-transistor
I *suspect* that your flyback diodes need to go on the 12V side of the relays.

>>2003281
>>2003251
Even better, right before the solenoids.

>>2003281

>>2003251
Just to make sure, you ONLY cut the Vcc line that comes out of the USB socket, correct?
I'm not familiar with the FTDI USB chips, so please excuse my questions:
You have the 27Ohm resistors on the D+/- lines, along with 47pF caps. Does the datasheet call for these specifically? A lot of modern USB-serial chips have them built in.
Pin #10 should go directly to C11 (100nF) by itself, then to ground. Pin #11 (RESET#) is tied to it for some reason. That doesn't look correct at all. The 3V3OUT is the internal voltage regulator, and it uses the 100nF capacitor for decoupling. This may be the cause of random enumeration errors.

>>2003281
>>2003286
His diodes are correct. The relay coils are driven with 5V+, while the 12V switched from the contacts.

>>2003017
>the black one
Wait, like the aluminium one?
>rotating cables and tips
The cable doesn't seem to rotate for me, at least not significantly. It might still be a vector for wear though. The tip does rotate somewhat freely on the other hand, but to apply enough torque to do so when soldering you'd be really riding on the thing.

>>2003096
>seeing this shit here
god the latest chapter was not something i needed to experience

>>2003281
He already has diodes across the coils of the relays. But if that's a solenoid valve he's powering with the relays, then he should probably use a diode across them too.
I assume J10 is the solenoid valve, but no clue what J8 is. Fuck EasyEDA for not having more symbols, use KiCAD instead.

>>2003251
>>2003296
Also to throw out there, check and see if the PIC has an internal pull-up resistor on the MCLR pin. It is active-low, so you need to use a resistor (4.7K - 10K) connected to 5V+ to keep the pin at a logic high for the PIC to run.

>>2003281
>>2003286

Does pic related look correct? Also, would this actually interfere with enumeration? Thanks for the help either way.

>>2003296
Yes, I only cut VCC. I'm not very familiar with these chips either. I basically copied a schematic used in a different product. So far it's worked fine when ONLY my laptop is connected via USB. When the entire board gets 12V and is connected to my computer via USB I'm getting sporadic enumeration and constantly unreliable LCD behaviour (dimmed backlight, not displaying what it's supposed to). The LCD doesn't even really look like it initializes properly. Perhaps a good start would be to make your proposed changes. Will post results

>>2003310
forgot pic

>>2003303
the PIC definitely runs fine. I have a shell running on the PIC that I can interact with when enumeration is successful

>>2003314
that would just turn J8 on constantly and with more current, and removes the required diode across the relay coil. do not do this.
you need the diode across the relay coil like you had before in >>2002750, and across any other coils/solenoids

resoldering connections is a good start, then i'd see if unplugging the laptop from its power supply will help

Did I mess up by connecting the OP amp to the diodes and cap at the begining and not the end like in the pink schematic?

>>2003356
of course
that way you get no negative feedback which is absolutely essential.

>>2003365
Fuck I though since they were part of the same track they could be connected at any point.
What can I read or watch to make sure I don't make the same mistake again?

Hello I am a literal retard I want a small remote controlled servo how do I do this on the cheap?

>>2003367
Oh, I checked again
Its alright, just confusing as you can see right now lmao

>>2003376
get a small servo, and use a cheap 433MHz wireless receiver + probably a cheap mcu like an attiny10 to remember the value it received. there might be dedicated rc receivers that do that memory thing without an external mcu though.

>>2003302
>Wait, like the aluminium one?
I should be more specific, It's pic related. You can see the sleeve which needs to be unscrewed and screwed back when replacing the tips.
>The cable doesn't seem to rotate for me, at least not significantly. It might still be a vector for wear though. The tip does rotate somewhat freely on the other hand, but to apply enough torque to do so when soldering you'd be really riding on the thing.
Yeah, I thought the same, you probably need to handle it really careless to break it, and you really shouldn't push your iron hard into the solder point, but I wanted to play it safe and get the most rigid and solid looking one, maybe not the most ergonomic (I still remember my first shitty iron where the power cable was only attached to the handle by the 2 shitty solder joints of the wires).
If everything is well then I will be happy to get myself the other handles, the thinner one you got certainly look easier to handle.

I've got this lamp that I want to fix, but I don't know what's going on..
I've got 8,6V on the output of the transformer pcb. No resistance between the transformer and the pcb in the pic. Does that make sense?

>>2003422
I forgot to mention, the lamp is rated at 3W. Can't measure directly at the led because it sits inside a tube and my test leads are too bulky. No idea how they put this thing together either..

>>2003388
Those ones have a collet to grip the tip. Makes it solid so it doesn't rotate, but doesn't let you hotswap bits. I can just pull a hot tip out with a small sheet of silicone and shove a different one in without having to wait for it to cool down. Had it for 2 years, nothing wrong with it so far.
The thinner one also has less stickout, which is a good thing in most cases, and is rather comfortable.

>>2003422
Draw an annotated circuit diagram. What do you mean by transformer? Are you feeding 8.6V directly into an LED with no current regulation? Because that's how you destroy an LED. LEDs need current limiting, and that sort is probably a 3V LED. If it's running at 8.6V and not producing light, the LED has probably gone open-circuit and needs replacing.

also do you call that a "decimal point" or "decimal comma"?

>>2003310
>I basically copied a schematic used in a different product.
Do you have the source of that schematic? I'd be interested to see it for comparison.

>the PIC definitely runs fine. I have a shell running on the PIC that I can interact with when enumeration is successful
>When the entire board gets 12V and is connected to my computer via USB I'm getting sporadic enumeration and constantly unreliable LCD behaviour (dimmed backlight, not displaying what it's supposed to). The LCD doesn't even really look like it initializes properly.

So if you only connect the board to USB, and not the 12v supply, how do you know the PIC is working? If you cut the Vcc trace, nothing at all should work when plugged in to USB only.
If you are getting power with USB only, even after cutting the USB Vcc trace, then you have a short somewhere.

Also do NOT change the diodes on your relay. Keep them as they are. There is zero reason to do this: >>2003314

>>2003433
Here's the rest of the lamp. Blue and brown is 230V. White and black becomes the brown and black you see in the first pic.
I didn't make this lamp, if that was unclear.
Tried the diode tester on my multimeter on the white and black wire and got 2,7V and 0,2V, if that helps..

>>2003296
I finally got home and had the chance to pull your schematic up on my computer, not my cell phone. I also dug up the datasheet for the FT230X.
The USB D+/- lines do need the resistors and capacitors, those are fine.
Also, the VCCIO, 3V3OUT, and RESET# lines can be all connected together like you have, with the capacitor to ground. Its fine, It looked strange on my phone earlier.

Something else I did notice though, you have a LOT of capacitors on your 5V+ lines. If you wanted to power anything from the USB Vcc line, you have to keep the capacitance under 10uF. That is a USB standard, too high of a value, such as the 1,500 uF on the LCD, can act like a short when plugging in the USB cable, and cause the USB port on the computer to stop working.
C10 in your schematic is a 47uF cap, and the datasheet shows that it should be a 4.7uF.

>>2003377
Damn, I see your point, the box on the opamp makes it difficul to see the trace

>>2003444
If the LED is broken, then either the cooling design was insufficient and the LED overheated itself, or the power supply failed from heat or lightning surges or something. The PSU is probably fine though, considering it's not outputting 0V or 250VAC. Some LED devices just have poor thermal design, you could arguably fix it by replacing a resistor value in the PSU to make it run at a lower current.

>>2003464
I'm guessing the LED gets fairly hot. That brownish semi-translucent wire is supposed to be solid red.
The 8,6V still doesn't make sense though, does it?

Should I be worried about sharing grounds and/or neutrals between 120VAC and 5v DC?

I've seen quite a few people do it, but it just seems sketchy as fuck to me. What happens if the neutral becomes the live? Like as in two prong plug put in backwards. I'm definitely not an electrical engineer.

>>2003606
It's good practice not to share an AC neutral with anything other than AC neutrals. And to keep them insulated from human contact too. Not nearly as big a deal in civilised countries, but where it's possible to swap the polarity of a plug, it can be a big deal as you've described. As for AC protective earth/ground, that's just fine to reference something else to, so long as it's just a reference and no current flows. Ground connections should never be in a situation where they can be confused or swapped for live.
If the device is thoroughly isolated from the outside, then it doesn't really matter either way, like the non-isolated buck converter PSUs inside LED bulbs.

>>2003286
>>2003281
dafuq is this? if your npn bjt cant handle 12v you need a better bjt. the guy who wrote that drek on stack probably sells relays to idiots on amazon with such misinfo. i got to92 bjts from boards i have salvaged from that do 300v 1a. i got motorola ones from a old kit my dad bought for nitinol pistons in the 90s. same company selling stuff all the diodes came individually sealed in plastic bag stuff that was stapled together. they can do 40v 600ma which is nothing to write home about its just the 300mhz switching they can do thats good

we need a charity for people who have bad bjts. for just pennies a day you can save bob from a life of relay dependence ... wont you help

>>2003714
>if your npn bjt cant handle 12v you need a better bjt
It's not the 12V it can't handle, but rather the multiple kV inductive spike that happens when you cut current through an inductor and it's E = 0.5LI^2 energy has to go somewhere as its magnetic field collapses. The diode across it prevents such a spike. It's called a "freewheel diode" or "flyback diode", there's a whole wikipedia page about it: https://en.wikipedia.org/wiki/Flyback_diode.. Not just relays, it needs to be used for any inductive DC load, like DC motors and solenoid valves. At very high frequencies, you can even get such spikes just with the inductance of your wires. It might be similar to the kind of ripples you get when using unmatched impedances in a circuit with transmission lines like coax.

On the other hand, feeding this inductive spike into a capacitor is also how boost converters work.

>sudo apt install kicad
fucking hell, was it always that easy?

>>2003733

>>2003718
the relay cant either. the contacts for the relay have whats known as leads. other shit on the board has leads. its a infestation. but the point is if you dont use a freewheeling diode its your own fault when the inductive spike daisy chains across your circuit and no relay stops it

>>2003739
>the relay cant either
Well, the breakdown voltage of the solenoid's insulation is usually higher than anything else in the circuit. Lead-to-lead, if it's a 2.54mm pitch, that's maybe 2mm between conductors (if you're using solder mask like a good boy), takes like 1.5kV to arc across. That's also higher than any common semiconductor, your transistor woulda given up the ghost before that happened. But it won't daisy-chain across the board, just jump the nearest path to force current through the relay. Just shorting through the one transistor will do this. Though it may well also put HV directly through the base of the BJT too, killing the MCU or shorting through its TVS diodes.

Actually I knew a guy who was using one of those crappy cheap adafruit-style h-bridges at 12V to drive a solenoid that was moving a magnet with an arduino. To ensure he activated the solenoid at the right time, he used back-emf sensing to tell when the magnet was near. But he just connected an analog input of the arduino directly to the drive coil, without any protection. So the arduino was constantly being subjected to 12V spikes. It heated up a fuckton from all the current going into its TVS diode, but somehow the circuit actually worked, and kept working. Fucking blinkies.

>>2003302
>god the latest chapter was not something i needed to experience
it's great, I hope it's not just an illusion or prank or bullshits like that

>>2003376
depends if you are smart enough to program an Arduino

>>2003773
I'm not and desu buying all the individual components ie battery, transmitter, receiver, servo, etc is already looking to cost well over $50 so I'm about to just buy a cheap ass RC car and use one of the wheels instead.

>>2003782
>buying all the individual components ie battery, transmitter, receiver, servo, etc is already looking to cost well over $50
not even 10$ bruh
>so I'm about to just buy a cheap ass RC car and use one of the wheels instead.
yeah, that would be the best for dumbfuck like you

>>2003827
Yeah go ahead and show me where I can order every one of those components for not even $10

>>2003842
go back to facebook gramps

>>2003848
No, no, go ahead. I'll wait.

>>2003857
>what is aliexpress
>servo
5$
>transmitter + receiver
3$
>battery
2$
you're welcome for the spoonfeeding, retard

>when your "tl074" has 7nA bias current
t-thanks aliexpress

>>2003861
What transmitter and receiver are you seeing for $3 dude

>>2003862
>he doesn't have a dedicated jellybean dealer
>he just gambles with the chinks

Anybody use MPJ for parts?
http://www.mpja.com/

>>2003923
i live near them, they have a comfy storefront with friendly old people. great prices sometimes on random transformers or power supplies or breast milk pumps or whatever the fuck they happen to drag in that week.

>>2003930
They have a nice inventory that hits the sweet spot between low prices and not having to wait 2 months for your shit to arrive.

>ordering my own pcb designs for the first time from jlcpcb

lads my tism is kicking in hard I just ordered after staring at my simple schematic for 2 hours straight thanks to the delusion that something is wrong with it

>>2003936
That's normal. You probably will find something wrong. Then you bodge it and update your schematics and board layout before ordering more boards. It's a learning process, and even engineers make the same mistakes.

>>2003936
something probably is wrong with it. just hope it's something you can repair. i've triple checked boards and still missed dumb mistakes.

>>2003938
I'll take comfort in the fact that at least china makes this process dirt cheap

>>2003939
the circuit itself (different stm32 controlled sensors with radio transceiver) I've tested with jumper wires, I just designed a board with pin sockets to plug in everything without having loose wires everywhere. I'm gonna feel stupid as fuck if this doesn't work.

>want to charge my watch but i lost the original wall wart
>whatever i will just use the phone one
>it works two times and then the watch stops charging
>write the chink company who made the watch
>oh you have to use wall warts with max 1A output or the charging dock will melt BAAAAAKA
holy shit what kind of retarded design is this? why the fuck isn't there some current limiting circuitry to limit the current so shit won't melt? And so I ripped open the charging dock like the EE chad that I am and it's literally just a cable and a pcb with pins, so i repaired the broken burned wore and added an lm317 in CC mode to provide constant .5C charging current, and then the watch will take care of cutting it off when the battery is charged, so now i can magically use any wall wart i want, holy shit fucking dark magic!
fucking incompetent chinks, how hard is it to include a vital 10 cent part in your $300 fucking product

>>2003184
they are literally filters

>>2003450
Thank you very much for this man.

Do you think that could interfere with LCD initialization?

tfw you will never be this comfy while fishing

>>2003972
How bored are you? lmao
Still, pretty neat.

>>2003943
>I'm gonna feel stupid as fuck if this doesn't work.
You should only feel stupid if you give up on it.

>>2003946
That's supposed to be in the watch, unless if it's a wireless charger.

>>2001473
>>2002297
>>2002297
I've had a play around with the ADAU1701 and trying to drive active speakers with it. Also been thinking about DIY cost optimized dac's on it.

Since you already have 4 x I2S out from the ADAU, you only need 4 slave DAC's. And the offerings from e.g. TI really point you toward getting multiple 2-channel DAC's. If price isn't an issue, then sure, you get to use less parts if you find multichannel DACs. For me, it was PCM5102 breakouts all around.

Does anyone have any experience with the ADAU145X series? The freeDSP classic schematic is pretty familiar to me, but I'm really missing the increased delay capabilities of a 'larger' DSP chip.

>>2003988
It's not for production anyway, an 8ch DAC from TI is like $2-4, headphone chip amps are ~$0.5. That's in quantity but even if doubled it's still not much.
Running multiple DACs & HPAs might cost more. Increases size too.
I've been looking at cirrus logic parts too, particularly the codecs but they cost a lot more, there's a portable codec that has 6ch output but it's $10.
There's also the issue with output impedance, even for chip amps it's not a stated spec.

You can buy a adau1452 board from china, has a stm32 onboard too. I'm thinking of buying a adau1701 board myself, instead of trying to put everything on one board.

>>2004001
Oh wow those 8ch DACs from TI are cheap. Noted.
Yeah, I haven't pulled the trigger because I've been unsure about the support for it. But seems that quite many people have got theirs running, so I probably shouldn't be this apprehensive.

>>2003894
https://www.aliexpress.com/item/4000834519025.html
literally less than one dollar, for both transmitter and receiver

>tfw the IR2184s I ordered from ali aren't SOICs but MSOPs
>tfw hand soldering 0.65mm pitch
>tfw there's no MSOP option in the datasheet
hope i didn't get chinked

>>2004036
Right, and how do you propose to control it then?

>>2004102
With a small MCU, like an ATTiny10.

>>2004109
I don't think you're really getting the whole remote control part of this project.

>>2004113
One for the transmitter, one for the receiver, what's the problem?

>>2003967
>Do you think that could interfere with LCD initialization?
Possibly.
My theory would be that if you tried to power everything up at the same time, the 1,500uF capacitor on the LCD would take much longer to charge and reach a working voltage. It would lag behind all the other parts in reaching a good voltage level to startup.
Depending on your PIC firmware, the PIC might attempt to initialize before the LCD is ready. You can solve that by using a much smaller cap on the LCD (a 1uF should be plenty, if you needed one at all), and using a delay in the PIC firmware to force the PIC to wait before attempting communication.

That's my theory at least, unless I could probe the board real time to troubleshoot it, I can't be certain exactly what is going on.

>>2001429
https://www.youtube.com/watch?v=qVz0C0vvZjc

Depending on your requirements you could consider this.

>>2004115
You now have an MCU on both ends. How do you plan to physically control the servo remotely?

>>2001468
Like this anon said
>>2001699
use a isolation transformer, can be had really cheap at scrap yards and then you just use a voltage doubler or tripler to get the voltage you need. Don't fuck with chokes, more weight and modern capacitors are orders of magnitude better than the ones used back in the day. An SMPS might give you grief as tubes are inherently high impedance devices and can pick up noise if you aren't careful but I don't see a problem with it if you take care with the design. The EL34 is not "just a guitar amp tube"; it has been used for ages in hi-fi; the Mullard 5-20 is excellent: http://www.r-type.org/articles/art-003d.htm Whatever you do, DON'T SKIMP ON THE OUTPUT TRANSFORMERS, they are the heart and soul of a tube amplifier. You may need to play with the feedback as you will inevitably be using modern transformers and they will be different in their characteristics requiring you to change the feedback network to get stability or you can leave it out at the cost of higher distortion. I recommend Hammond for the OPTs as I've had good luck with them in the past. If you really are on a budget you can use power transformers but the high end may suffer as a result; 240V:6V transformers with a 4 ohm load will give you roughly 6.4k at the primary. >(240/6)^2*4=6400
Also check out funwithtubes.com and good luck.

>>2004123
anon, I...

>>2004126
Oh and one more thing, using power transformers as a substitute for the OPTs will require you to ditch ultra linear (distributed loading) and do something about the supply for the screen grids as well as costing you distortion performance as well. My most recent amplifier I built uses power tx for the outputs and has 0.8% THD and 5% IMD at 12W output, is only down 2dB at 30Hz and damn near flat all the way up to 35kHz without any feedback as measured by an Amber 5500 distortion analyzer. A scope and analyzer go a long way in nailing the performance but if your scope can do FFT that may be of help. Do your research, a tube amp may not match transistors on paper but built right they sound phenomenal.

>>2004130
No please tell me. I need it to spin when I press a physical remote button. I literally just need an rc car basically just shaped differently.

I'm experiencing some parasitic oscilation on this build, I've read that unintended oscillation is pretty common in these kind of high gain feedback circuitry and a way to fix it is "RC pair between polar inputs of the opamp".
I'm assuming an RC pair is a resistor + cap in parallel and it makes sense since putting a random cap in between 2 and 6 mutes the interference completely.

How do I know what values to use for the R + C? Electrolytic, ceramic or poly? Will it affect the tone?

>>2004214
forgot pic

Should I go ULN2003 or ULN2803 for jellybean purposes?

>>2004123
So first you preprogram both MCUs. Say, the first uses its ADC connected to a potentiometer, and whenever the analog value changes(after some threshold), it spits out serial data of that value. Perhaps something like RS232, with its start bit, 8 data bits, and end bit, which would make framing relatively easy. But personally I’d go with something involving Manchester encoding. Either way, the serial signal goes into the 433MHz transmitter and performs on-off-keying to the waveform. The 433MHz receiver picks this up and sends it to a digital input on the second MCU. It uses this to update its PWM duty-cycle, which is fed directly into the servo (or maybe with a low pass filter in the middle). Whenever it’s not receiving a signal, the second MCU will just keep outputting PWM at the last updated duty-cycle.

This is the kind of easy stuff that is perfect for doing on an underpowered 8bit micro. Could even go for a Padauk 3c micro, if you have the programming hardware and software, and can handle the one-time-programming.

Anyone have any experience with sending data from an arduino to a raspberry pi? I'd like to utilize the arduino's analog ports for various sensor readings and then send it over to the pi for data logging and remote access. I've read up on the ard's TX and RX pins, but it's not as simple as just serial.write(), is it?

I'm doing a garduino type of deal for next growing season.

>>2004363
I should also mention a simpler USB connection wouldn't be very practical in this situation.

>>2003936
My first PCB, I went downloading footprints for specific components from the manufacturer just to make sure nothing got fucked up and somehow I still ended up with the source and drain swapped on my power mosfet

what do you think

>>2004426
I remember thinking that when I saw that lmao

>>2004426
So𝅶y cam for his horse dildo borescope.

What the fuck is this atrocity?

>>2004426
I'll never undestand why they make that face lmao

>>2004363
I’d just use two of the pins for serial. Both devices should make that pretty easy. The rpi will almost certainly have RS232 pins on its GPIO, though I remember something about RS232 on Linux being shitty about the different pins. A better option might be to use a finer resolution ADC (ADS1115 is common for blinkies) directly via I2C with the rpi. Assuming it doesn’t need to be interfaced with fully real-time. Could also use a comparator and the built-in audio DAC plus some code to make a successive approximation ADC out of the pi, which might be fun.
Also don’t forget the logic level shifters.

>>2004377
Did you place them manually in Inkscape or something, or did you do it via KiCAD or similar? Because it’s pretty hard to mix up pins on KiCAD.

▲
▲ ▲

testes testes
1, 2, ...3?

>>2004217
Do you have an actual circuit diagram? Oscillation is a product of gain and a phase shift/delay. Any RC low-pass network can give you that delay, which can be an integral part of your circuit, so you need to eliminate gain. Even the propagation delay/slew rate of the op-amp can be sufficient, causing it to oscillate at many MHz. IIRC, a capacitor from the output to the inverting input will give it strong negative feedback at high frequencies, which should decrease the gain enough to prevent oscillation. Choosing a small enough value should prevent oscillation and also not effect how your circuit works and sounds at normal operating frequencies. That's what stopped my headphone amplifier from producing 300kHz and demodulating AM radio.

I use a troubleshooting tip I like to call "cap on a stick". Get a capacitor, 10nF or so, bend the legs away from each other, and grab one with an alligator lead. Clip the other end to ground and start poking it while it's on and scoped/being listened to, so you can figure out where a cap needs to be. If caps to ground don't do it, then caps to Vcc or the inputs or outputs are what to test.

>>2004448
>>2004466
yuck

>>2003862
Should've bought from LCSC

>>2004038
Don't buy parts from Ali, most of them are fakes. Buy from LCSC if you still want to buy from the chinks

>>2004120
how do I make dead time with this config? I would prefer to only use 1 PWM output

>>2003920
share it pls

>>2004590
wait in the end he still uses the IR2153, ok then it just speeds up the rise and fall time

>>2004585
I'm buying from one reputable seller, not just sorting by cheapest or most orders.

Also those were actually my SI5351s, oops.

I wanna order some PCB's soon, but I'm too shy to upload my own u_u

Are there any free devboard gerber files for cheap FPGAs, something I could get for $2 a chip and just solder together? Like the ICE40UL1K-SWG16ITR on Digikey?
My time is worthless desu

>>2004591
tayda for common parts (~$2 shipping), digikey for big boy parts (~$5 shipping)
haven't uses LTSC but they seem pretty legit too

How do I filter USB power noise? For an audio board.

>>2004499
Cap on a stick it is then I like the idea, why did a cap from inverting input 1 to inverting input 2 seem to solve my problem? I'll try output to the inverting input.
To be honest the circuit has more gain than the effect it's trying to imitate so I've checked and double checked all my values twice and I haven't found any problems, maybe there's some design issue with the veroboard layout.

>>2004692
Multiple-order LC filters. Say, a multi-stage Pi filter. There's a limit on the input capacitance of a USB device of 10µF, but by putting an inductor after it and following it with more capacitors, you should be able to get better filtration, especially of high frequencies from SMPSs. But too high of an inductance will make it difficult for it to respond to sudden load changes, if that's something that might occur.

Still, USB is hardly desirable for most audio purposes. If no power is required, you could put the data through an opto before it goes through to the analog stage (say, as an I2S link from MCU to DAC). Being able to run things on a 3.3V regulator would also help.

>>2004711
You already have a cap from 1 to 2. But it isn't that large. Simulate to see what effect a larger capacitor will have on normal operation, 1nF should be fine, maybe. I think a large resistor in parallel with the diodes (1MΩ-10MΩ) might also help.
What op-amp is oscillating?

Also please don't arrange your op-amps like the IC is arranged, it just makes your schematic messy. You should be separating each subcircuit in their own little area, connected with net labels. All the footprint pin assignment and such is done for you when you import the netlist into the board designer. Crosses over crossing wires also isn't necessary, though not really an issue either.

>>2004720
I'm not sure at what stage it's oscillating so props for pointing me in the right direction.
I'll hook up the osciloscope and see if I can find what op-amp is causing trouble to at least remove half the components from the equation.

The small 51pF C4 capacitor across the diodes works as a low pass filter, softening the corners of the clipped waveform and mellowing out the high end of the distortion.

I was scared to fit a readily available 56pf on c4 (c2 on my diagram) because I didn't want to sacrifice high tones, but I'll give it a pop, huge resistor in diodes is a great candidate too, I'll give it a shot.

Thanks for the feedback and I'll definetly not arrange my diagrams like this in the future, it was my first diagram ever, I'm a coder and my code is bad and spaghetti like so I guess that bled into my electronics.

>>2004733
Also I don't doubt your recomendation but why was I told to put a RC combo between polar ins and not out to in like you mention?
Just trying to learn as I go to avoid asking these dumb questions next time I encounter unintended oscilation.

>>2004733
Wait you already have a resistance across the cap/diodes, a 1M won't do anything extra.
As for the capacitance, 51pF is a really small value, it will soften the corners a little, but not by much. Going up an order of magnitude shouldn't effect the overall sound much at all.

>>2004736
A high-pass RC link across the inputs may well help it, but I couldn't say how much. I'm not an expert by any stretch.

>>2004761
Great! I'll gradually increase the capacitance and see if I arrive at something good.

About the RC, correct me if I'm wrong. But I should see what range the resonance ocurrs in, and calculate what freq to cut-off suing this formula?

If a Li-ion cell measures 0V that means protection tripped right?

>>2004733
datasheet has a couple graphs on the gain and frequency. They are dependent on the load. You could try estimating the loop gain and phase (just exclude the diodes) and seeing how it relates to the device curve.

>>2004795
And you could try giving us the oscillation frequency, it could help.

>>2004786
>>2004761
Back! I had a polyester 1nf lying around, wich is a big leap from a 56pf ceramic but it got the job done. I'm gonna buy some tiny ceramics to try them in increasing order till I get the intended result.

>>2004795
>>2004796
I'm tempted to do this simply because I'll learn from the experience, I'm satisfied with the issue resolved but it was mostly a prod it with components till it fixes itself

Pulled this out of a bluetooth speaker. Maybe I can learn something about audio circuit design.
Pretty fancy for a BT speaker.

>>2004798
what is the oscilation frequency?

>>2001736
how do you manage cats around your diy space?

>>2004839
Let me get back to you on that, I'm using an analog oscilloscope from the 80s

>>2004896
Van de Graaff generators

>>2004907
i didn't ask about your cbt routine

>>2004903
Sorry chief, that's as clear of a picture I can get.

So I'm going to have to trust my 10$ multimeter and say between 2k and 8k Hz if I fiddle with the knobs on the effect

>>2004896
slap their face whenever they enter the vicinity

>>2004910
You didn't ask anything then.

the NAU7802's datasheet kind of sucks. for example it leaves the common mode range unspecified for pga gains 2 through 32, but it's unclear in a dozen other ways. anybody know of good posts/experiments done with the NAU that I can reference before I use it in a circuit and get fucked?

>>2004996
SparkFun has the NAU7802 on a breakout board:
https://www.sparkfun.com/products/15242
Click the "Documents" tab under the "Add to cart" button to get links to a lot of great info on it.

How do I get into SMPS design? I'm going to need to design one for a project (luckily, not a professional one).

>>2005059
Research existing topologies, read datasheets, and build example circuits.

>>2004836
Looks like a right pain to reverse engineer. It's going to be some variant of class-D, if that helps. Noteably, it has 8 output inductors, not 4 like I'd expect for a stereo amplifier. Also only focus on what's after the PCM5121s, since they're the DACs. Not going to be able to reverse engineer any digital circuit like that without a logic analyser and a bunch of time.

Then again, since it's a wireless device, there might be a full schematic uploaded to the FCC site.

>>2004914
>that's as clear of a picture I can get.
It's not triggering synchronously at all. Adjust the trigger point to ensure it's triggering off the channel properly, it might also be aliasing on something so try increasing the timebase a bunch to see if anything high up there triggers properly. Holdoff might also be worth messing with, though it shouldn't be necessary to view a simple repeating wave like this.
Got a good SNR there though, and it's sinusoidal, which is somewhat interesting. What's the V/div?

what gauge wire should i use to go from a 24v psu to a buck converter to drop it down to 5.1v to run a raspberry pi 3? also do i use the same gauge wire going in and out of the buck converter?

>>2005122
The current draw of the Pi is like 2.5-3A max (15W). You don't need beefy cables. 22AWG is more than enough.

>>2005125
thanks anon

>>2005110
It outputs 4 channels, not stereo. One for each driver. The DACs are stereo and so are the chip amps.
The DACs also have some filters built-in like crossover, which can be controlled with an external device, and indeed they're wired over I2C to the BT SoC, which is a CSR 8675. Which also has dual I2S and a DSP so I wonder why they didn't use that. Or maybe they do?
It has a DFU mode too, I wonder if one can dump the firmware through that.
This thing is quite powerful for a BT speaker. It comes with a 40W power brick.

>>2005125
>The current draw of the Pi is like 2.5-3A max (15W). You don't need beefy cables. 22AWG is more than enough.

this is wrong. the RasPi gets weird if it gets below 4.75V, as i've experienced when using thin cables. replacing them with 18AWG fixed the weirdness from cable losses.

>>2005214
Were the wires you used 30 feet long? 22AWG (not THAT thin) is fine for a Pi, dude. Been there a million times.

>>2005153
Oh, 4 channels. Are the speakers far enough apart for that to be significantly different from just 2 channels?
>I2C and not I2S
Sounds odd, yes.

>>2005153
Is this from a soundbar?

>>2004914
learn2trigger

>>2005110
>>2005110
Got it boss.

If I adjust the knobs on the guiyar effect the oscilations go from
highest pitch: 3 separation between highest and lowest at 50u seconds, wich comes to 1 shift every 150us... 6666.6666666667 Hz ? I'm not sure on that math...
On the other hand the lowest is 2 squares at 10us, so 5000hz.

Anyway, I played with the values of c4, gradually incrementing values, the higher the value the lower the whistling and eventually at 680 complete silence and the effect works as intended. I've compared the sound between 56pf and 680pf at C4 and I'm under the impression that under high gain output the sound is noticeably less pitched and less gainy, but under any setting less than max there is no audible difference to my ear.
Am I correct in assuming that's how this cap has changed the circuit?
Sorry if I've required more handholding than I anticipated

>>2005238
This anon basically taught me in 5 min, what a legend

>>2005245
>This anon basically taught me in 5 min, what a legend
Dude if you can't trigger into a sinewave just give up

>>2005245
A 20kHz oscillation means it's definitely not oscillating by slew-rate alone. Increasing the capacitance as you've done has fixed it, but I suspect there's a better way to tackle it. Assuming there's a low-pass RC network somewhere causing that delay, a small cap in parallel with the resistance of it might be a better option. Can't decipher your circuit diagram to figure out where though.

>>2005248
I refused to give up and now I know

>>2005264
Good job bro. Now what is the frequency ree

>>2005271
>what is the frequency ree
Kenneth

>>2005263
I also suspect there's a better way, since I've realized it affects the output sound more than I initially realized. Possibly because I'm filtering frequencies that are in the guitar's range.

I don't blame you for not understanding my diagram, I had to read it twice and use your cap on a stick method to determine that there's a low pass RC labeled R12 and C6 witch feed directly into the second opamps -in. putting any value cap in paralel with R12 without toucing C6 rises the pitch of the intereference ever so slightly.
Also putting a small value cap in paralel with the 1M resistor that separates grand and input seems to make a significant difference.

>>2005303
Honestly, I'd redraw your circuit diagram, with linearity. I.e. the signal always goes from left to right. Then probe where you're getting the noise, and probe back from that to find the source of the oscillation.

Pic related. I haven't drawn annotated boxes around anything so it could be better, and I've split it up to stop it being so long, but in general it's easy to read. Also it has some glaring issues that I had to bodge out, so don't copy it, though it's a circuit with very similar purpose to yours.
Important to note is the use of power nodes (Vcc, Vee, GND), the lumping of relevant parts of the circuit together (power cluster, main signal path, individual effects and switch), and the shortcutting of otherwise long interconnecting wires by using net labels (vGainIn, vGainOut, softClip, hardClip, etc.).

What's this capacitor's capacity?
The code is f2.00 C, so 2 or 20 pF?
I'm measuring 56 pF, so it is most likely the culprit why my gamepad is not working, but what new capacitor do I need? The marking is strange. The C at the end indicates it should be under 10pF, but if I read the code as 200 it is 20pF.

>>2005315
Looks like a crystal.

>>2005308
Those are some great tips and I can definetly see the benefit of redrawing.
What I originally did was translate from veroboard do schematic but now I more or less unerstand the journey the signal makes across the different stages, so I'm sure re-drawing will be to everyones' benefit.

Thanks for helping me out here! truly apreciated!

>>2005320
Probably ceramic resonator, but yeah, basically the same thing.

>>2005330
Thanks! Found a similar one. I'll change it anyway. Maybe it will help.

>>2005332
Try to resolder the old one first, but don't overheat it.

>>2005339
It is already desoldered as well as all capacitors. Resistors, pcb traces and the cord seem to be fine, so I thought it can only be the capacitors or the microcontroller.

>>2005348

>>2005348
The resonator is delicate and prone to failure from a hard drop. The caps and resistors are probably fine, but check them anyway. Reflowing the wire connections is also a good idea.

Two 100nF capacitors are 85nF and 75nF each, the rest is ok. I checked the cable from the Playstation connector to the first resistor on the pcb with a multimeter. All the wires have connection. Thanks for the tips regarding the resonator. I'll replace it with a new one or a 2mhz quartz.

>>2005361
Sounds good. One more thing. Check resistance (rather than continuity) of the wires from the console to the controller. If they're all in the same ballpark you're good.

>>2005368
Thanks. I'll report back later. It's 2pm here in Germany, so I'm off to sleep.

>>2005372
>2pm
2am

>>2005372
Okay, Hans. Sleep tight.

>>2004896
There is nothing to manage, all that my cat does in my room is sleep. After he wakes up I let him outside for the rest of the day, he loves hunting and would never miss the fresh cow milk.

I'm correct in assuming this is an RC damper, a flyback diode and a TVS all together?

I know literally nothing about electronics or wiring, but I want to convert a humidifier to 12v. Keep in mind the only moving part here is an electric fan. So would this be any more involved than replacing the 120v fan with a 12v? Would the cord and wiring designed for 120v cause issues?

>>2005454
It's not really a flyback diode. The UF4006 blocks any current in the positive direction, so current only flows through the TVS in a loop from the transformer. I wouldn't call that a flyback diode, since I doubt it's meant to happen regularly, if it did then the TVS would quickly overheat. In normal operation, the energy caused by the primary side's current should be taken out by the secondary side (and the TNY's power supplying winding) before any kind of spike appears.

>>2005471
>replacing the 120v fan with a 12v
That would work just fine, so long as it fits and has at least equivalent IP and humidity ratings.
>Would the cord and wiring designed for 120v cause issues
Probably not an issue, chances are it's nowhere near it's current limit when running on 120V. Measure its gauge first, then decide one way or the other.
Though you'd better chop off the mains plug and crimp/screw/solder on a normal DC plug instead. Like a T plug or XT30 or barrel jack or whatever.

>>2005218
The full range drivers are 3cm from each other. The tweeters 15cm. They are placed at an angle though. It's the kind of speaker you put in your room plugged in, despite having an internal battery.
Also it's both I2C and I2S. I2C for control.

>>2005219
It's from a HK Onyx Studio 3.
Soundbars should have more channels.

Also it has an issue with the battery seemingly draining itself. I got an hour or so out of it after it's charged, but the next day it would shut down just a minute after turning on. Annoyingly this happens even if it's plugged in.

at what point do I stop messing with complex circuits and just use an arduino?

>>2005556
The moment you thought: fuck this it's easier with a uC

>>2005308

there's been a plague of drawing idiocy here recently.
for those who dont know: grids are for drawing your diagrams. when you wanna show them off, you turn OFF the frackin' grids.

>>2005308

there's been a plague of drawing idiocy here recently.
for those who dont know: grids are for drawing your diagrams. when you wanna show them off, you turn OFF the frackin' grids coz they make your drawing look like UTTER SHIT.

>>2005556
when you complete your sex change

What connectors would you use for low profile stacked or side-by-side board connections?

>>2005578
Point taken.

Is there a variant of 2.54mm pin headers that are a little thinner and fit into breadboards better?

>>2005651
the round one

how do solar micro inverter works? I thought you cannot connect inverters in parallel?

>>2005611
cursed image

>>2005556
when you recover from your head injury
>>2005471
there is a piezo element that vibrates on the bottom and associated circuitry.

>>2005665
Of course you can.

>>2005676
>Of course you can.
wait really? Don't you need to synchronize them or something like that?

>>2005678
Every source connected to the grid must be in sync, regardless if it is a gigantic 300MW generator or a micro inverter. In fact grid frequency is used to control the power output of the sources (google frequency droop control).

What you cannot do is connect two voltage sources in parallel without anything between them. (short circuit, indetermination). Regular grid stuff has miles of cables and transformers between them, inverters have output filters.

>>2005682
>Every source connected to the grid must be in sync
how do they sync to each other?
>inverters have output filters.
what do you mean by this?

>>2005684
If A=B and B=C A=C anon.

is there something like a rotary switch but a linear one instead of rotary

>>2005767
slide potentiometers? or a switch?

>>2005767
Search for "slide switch x-position", x being a variable for poles.

>>2005732
what?

Hi noob here

If I put 12V DC on a LM7805 regulator (lets say from a 12V 5A power supply) rated to output 2A, the current draw on its 5V pin will be limited to 2A. However, what about the 12V pin? If I had two circuits, would I still be able to draw 5A from the 12V pin? Or would I have to connect my 12V circuit to the PSU directly?

In other words, how do I split 12V into a 5V and 12V circuit and maintain the ability to draw 5A on the 12V rail using an LM7805?

>>2005836
If 2A is drawn from the 5v regulator the draw on the 12v supply is roughly 2A * (12/5) = 4.8A. The extra current is dissipated as heat in the regulator.

>>2005859
Very nice, thank you.

I'd like to get my understanding of theory/ circuit analysis up to snuff. Can I ask how that formula is derived?

>>2005153
>It outputs 4 channels, not stereo. One for each driver. The DACs are stereo and so are the chip amps.
Its only 2 channel. The unit has 4 speakers, both channels have a tweeter and woofer. They are doing a bi-amp setup so each speaker gets a dedicated amp. The SOM supports two PCM/I2S channels, and is most likely programmed to use internal DSP to output the higher frequencies on one output, and lower frequencies on the other. Each DAC is 2-channel, but this setup allows processing of a much more narrow band of frequencies.

Why?
Quality and power. This setup allows the audio to be broken down into multiple components and processed/amplified individually. You can squeeze more quality out of handling a smaller band of frequencies.

I've designed tri-amp systems with a similar style. Its not common, but its a real thing.

>>2005870
that's what a linear regulator do, basically a glorified resistors. Their efficiency is Vout/Vin.

>>2005836
>>2005859
The 7805 is a linear voltage regulator. The output voltage is dropped, but the current stays the same.
If the Output is 5v@2A, the Input will be 12v@2A. Thats how a linear vreg works.
Keep in mind, you dissipate the excess as heat.
The 7805 Has to dissipate 7V@2A = 14W.

>In other words, how do I split 12V into a 5V and 12V circuit and maintain the ability to draw 5A on the 12V rail using an LM7805?
Assuming you need the 2A on the 5v rail, and 5A on the 12v rail, you'll need a power supply that can output 12v at 7A.

>>2005896
>that's what a linear regulator do, basically a glorified resistors
They are semiconductors and use transistors to dissipate the extra energy. Not nearly as basic as resistors.
>Their efficiency is Vout/Vin
Pout/Pin is more correct when calculating efficiency for anything.

>>2005890
I mean the digital crossover outputs 4 channels, 2 for each side.
The BT on this thing only does SBC, I wonder why they cheaped out on that.

>>2005905
>I mean the digital crossover outputs 4 channels, 2 for each side.
Gotcha, we're on the same page, but not the same language.
A "channel" is referred to as a dedicated track with unique audio data. Such as Stereo = 2 channels. When you split them up into various frequency passes, they aren't called "channels", they are just "Right Channel High Pass" and "Right Channel Low Pass".
That is the verbage used when designing these stupid things. A little confusing at times.

>>2005897
> Assuming you need the 2A on the 5v rail, and 5A on the 12v rail, you'll need a power supply that can output 12v at 7A.

>>2005904
> Pout/Pin is more correct when calculating efficiency for anything.


For give me, but Pout/ Pin is

Pout = 5V * 2A
Pin = 12V * 7A

That's 10 / 84 = approx. 0.12 watts, which doesn't seem like a lot. What am I misunderstanding here?

I think it's the 2A * (12/5) in your original example that's tripping me up.

>>2005913
I posted only these:
>>2005897
>>2005904

For Pout/Pin, I was referring to only the 7805 regulator. The Output is going to be 5v constant. You said you need it to output 2A, so our output from the 7805 is 5v@2A. Pout = 10Watts. Because the 7805 is a *linear regulator*, the input current is equal to the output current. In this case, because your output current is 2A, the Input current is also 2A. You said you have a 12v power source for the input, so the Input to the 7805 will be 12V@2A. Pin = 24Watts.
So to calculate the efficiency, Pout/Pin = 10W/24W = 0.4167, or 41.67%.
That is ONLY for the 7805.

You also asked >how do I split 12V into a 5V and 12V circuit and maintain the ability to draw 5A on the 12V rail using an LM7805?
Based on our previous calculations, your 7805 that provides the 5v voltage will use 2A of current. In order to have 5A available from the 12V supply, you'll need a power supply that can output the 2A for the 7805 to use, and the 5A you'll need for 12V.
So you'll need 2A(for the 7805) + 5A(for other 12V power) = 7A total from the 12V supply.

>>2005480
Thanks.
>>2005673
>there is a piezo element that vibrates on the bottom and associated circuitry.
For what purpose? Haven't actually pulled it apart yet but they only need a fan.

>>2005918
>So to calculate the efficiency, Pout/Pin = 10W/24W = 0.4167, or 41.67%.
I forgot to add in there, the equation is specifically (Pout/Pin)*100. You have to multiply the answer from Pout/Pin by 100 to get the correct percentile. I'm used to doing it in my head, sorry.

>>2005684
Inverters obviously need to monitor the mains frequency and ensure that they're producing an in-phase output. In the case of large rotating synchronous generators at 60Hz, more current drawn from the grid means more load on the generators, which slow down; any generator not slowing down will have more load drawn on it, so it's a natural negative feedback loop. Simple electronic inverters cannot do that, so they have to actively follow the mains.

Inverters have LC filters that smooth out the waveform into a more sinusoidal shape, but they also serve to buffer any slight phase differences by storing energy as it comes out of (or goes into) the inverter.

>>2005904
> >Their efficiency is Vout/Vin
> Pout/Pin is more correct when calculating efficiency for anything.
For a linear regulator, Iout=Iin so Pout/Pin=Vout/Vin

Frenly reminder for the next baker:
A request to add CNLohr to the related youtube channels.
A request to include a Popular Mechanics archive to the reading materials list.

>>2005946
forgot link
https://worldradiohistory.com/Popular-Electronics-Guide.htm

>>2005946
>Popular Mechanics
you know what I meant

>>2005918
>>2005921

Thanks, that's very clear

What amount of voltage ripple is acceptable in the primaries of a SMPS with a flyback topology? I was aiming for 1 Vpp, but ended up with a massive capacitance, I checked another design online and I calculate that it has a ripple around 15Vpp

>>2005946
Done the poptronics, but why CNLohr? Not entirely against it, but he seems to be more of a software guy with some lean into MCUs. Not that good of a fit in my opinion.

>>2005965
Doesn't really matter what the primary side mains ripple is, you just need sufficient capacitance to not drain much when pulled on by the transistor. In other words, E = 0.5CV^2 >> 0.5LI^2.

>>2005970
thanks m8
have space in return

>>2005970
>but why CNLohr?
His ATtiny NTSC VHF transmitter is pretty neat and there's crossover into MCUs here anyway.

>>2005979
There's an mcg at the moment.

>>2005395
i was talking about indoor ones though

>>2005965
whatever the regulations in your local area or design parameters are.

>>2005919
Most humidifiers I have used just vibrate a piezo element to yeet water particles out of them in a mist.

anybody have the eevblog BM235 meter? i'm tired of buying chink meters that are supposedly fine but work like shit in practice. i was looking at flukes but i'm really unimpressed with their <$200 offerings. the eevblog meter is well reviewed though i don't trust australians.

>>2005995
Can't imagine having one, must be a chore. Maybe just keep him outside your room/workshop.

>>2006033
There are three common kinds of humidifier. Some use a heater to boil water, some use a MHz piezo, and some (like the op’s) use a high surface-area wick to soak up water and use a fan to blow air on it. The piezo model has the disadvantage that it kicks up particles of liquid water that then evaporate, leaving any salts and gunk in the water to crystallise out in the air and leave a fine powdery coating in the nearby area. Using distilled water would be pretty expensive. The heater models are pretty power hungry, though if you’re using resistive heating anyhow it won’t make a difference; the other models are swamp coolers after all. While the wicks do need cleaning or replacing, those models seem to be the most effective in water evaporated per joule. They’re also not fucking electrode-boilers.

t. watched a technology connections video on them last week

I need to interface with a serial port using a CH340G, but the serial port is a proper ±12V one. While this IC is only 5V tolerant, the serial-transceiver IC on the appliance accepts 5V as a 0 and 0V as a 1, despite them being technically invalid. So with some diodes and transistors and resistors or whatever, I can give the CH340G a safe input voltage, and its outputs will work just fine.
Are there any potential issues with this? I only plan on using it for this one appliance. Not sure whether I'll have to invert my bits or not though. The appliance relies on the CTS or RTS pin (forgot which, it's the one going into the appliance) to actually give me any data, which is a bit of a pain.

Does anyone make a dimmer or multiposition switch i can use to replace the on/off switches on my desk lamps. If no one makes them how difficult would it be to throw a variable resistor into the housing?
I only use LED bulbs anymore and would like to be able to control the brightness.

>>2006265

- a real designer would pop in a max232 chip and call it a day, having made a universally-compatible RSR-232 device.
- potential issues: less noise immunity, shorter possible cable runs. not a big deal, usually.

>relies on the CTS or RTS pin
this is to prevent buffer overflows, from the old days when gadgets had tiny buffers. if data is sparse, then you can get away with hard-wiring one or both to appropriate levels.

>invert my bits or not though
info should be in CH340G datasheet. too lazy to look, but my guess is it expects to be followed by a max232-type chip that inverts RX and TX, but passes other signals straight.

>>2006287

you have several options, but putting in a pot is definitely out, unless you enjoy fire and smoke.

simplest fool-proof method way is to get an ikea-type light dimmer for $20-$30.

other options include (1) adding a touch switch, which usu has 3 light levels + OFF, or (2) a wireless dimmer, also available from Ikea, or (3) rewire the socket as a 12V unit and use a PWM module like this https://www.superbrightleds.com/moreinfo/single-color-dimmer-switches/ldp-2a-12-volt-dc-single-color-led-dimmer/61/

>>2006297
>max232 chip
I've tried using a MAX232 before, was a real fucking pain. Its self-generated power rails kept collapsing and "boot-looping" if you want to call it that. Was following the recommended circuit too, and I'm pretty sure I had sufficient supply capacitance. It was literally more reliable to put diodes on the output pins to generate the ±11V rails for transmission purposes.
Also I need to get the data to my computer one way or another, max232 + usb-compatible mcu is like 5 times more expensive than this shitty IC.
>if data is sparse, then you can get away with hard-wiring one or both to appropriate levels
No, I'm pretty sure it only transmits data upon seeing an edge in the CTS/RTS pin. Anyhow, the CH340G has both so I'll use them.
>my guess is it expects to be followed by a max232-type chip that inverts RX and TX
Would need two of them if I was using both DX+RX and CTS+RTS.

>>2006316
I suspect the reason he's asking and specified "only use LED bulbs anymore" is because his LED bulbs don't work with dimmers. To which there's only really one option, buy LED bulbs that do. That said, I'm planning on making some circuits to fit inside the housings of LED bulbs that work with a remote control. Should have bought some of those IR receivers I guess, LEDs too. Be neat to connect it to an MCU with a hexadecimal or octal keypad, and send an MCU in the bulb abstract commands. Or maybe even figure out some way to program it via IR for really complicated stuff like time-changing brightness, or responding with internal sensors.

>>2006339
>I've tried using a MAX232 before, was a real fucking pain.

it's famous but it's also 30 years old. Maxim now makes hundreds of modern variants with much better performance all around. the problem is choosing 1 from hundreds.

>>2005924
So they get the voltage value and position of grid and set pulse width and output voltage position based on that value and the output must go through a low pass filter, is this correct?

>>2006378
Probably, taking into account the effective phase shift of the filter. But you wouldn't necessarily have to measure the grid directly. The more out of phase the wave is, the less energy comes out of the filter, which is reflected in a higher voltage out of the filter or distortion of it or whatever. Because I think that phase shift of the filter is a function of output current. Assuming you don't end up pushing hundreds of amps into or out of your inverter with your testing sequence, you could find the optimal phase to drive the FETs at in order to produce the output current you desire.

>>2006398
this sounds more complicated than what I thought. Anything to read about this?

>>2006418
I'm just guessing from intuition. You could try simulating it though.

>>2006446
>>2006446
>>2006446
NEW THREAD

I bought a 24V-20A power supply on aliexpress but like the nigger I am I forgot that I needed a 12V one. What are my options to step down the voltage? Complete retard btw but I can probably follow instructions

>>2006564
If you need anywhere 20A, it will be cheaper to buy a new power supply. Buck converters over 5-10A are expensive. But if you're savvy, modify the existing one to output 12V.

Also new thread>>2006446

>>2006729
wait i didn't see your post in the new thread, disregard

>>2005995