/diy/ - Do It Yourself

The equalisers posted don't help me at all. https://sound-au.com/p-cat.htm#equ
I'm looking for a basic baxandall type equaliser for a HIFI system.
So is picrel sufficiently good, or are there better circuits for this application?
https://www.circuitstoday.com/passive-tone-control-circuit

>>2575936
>>>2575933
So did I get chink'd? Was the 2uA figure ever true in the first place?

>>2575970
Yes, you did get chinked. Get a refund

>>2575966
>http://guitarscience.net/tsc/baxandall_passive.htm
Here you have a ton of equalizer configurations, just pick whatever you like and build it. With passive type circuits you need amplifier in front of it to bring gain back to 0dB or you can also build active version like pic related.

I work in a contract manufacturer that assembles PCBs.
I'm one of the very few people that actually knows anything about electronics.
In the last couple of years, we've started offering repair of power electronics and I'm basically running the program.
The pay isn't amazing but I'm pretty much left to my own devices and whenever I'm doing a project for myself, I throw all the components I need on a purchase requisition and get the company to buy them.
I say I need the components for test development or prototyping and nobody asks questions cause they've no idea about electronics.
I've even had them buy me fancy development boards a few times and then sold them on ebay.

>>2575978
you cheeky cunt :^)

>>2575977
Thanks Anon. The cicuit is very similar to the baxandall I posted earlier, using a single op amp as active element.

I want to make a temperature logger. Are there any decent sensors that don't require me to sell my kidney and bone marrow to afford them? I don't want DHT11 tier sensors, I want something good.
Somehow I think manually calibrating an NTC thermistor is my best bet here.

Damn, maybe I'm just too jaded and cynical

I bought a soldering iron and tips for my station... And lead free solder because it was cheaper this way.
What should I expect from lead free solder? Chinks claim it is Sn99 Ag0.7 Cu0.3
I never have used lead free solder for electronics so idk.

>>2576013

>>2576026

>>2576025
just takes a bit more to heat up. use 350 C on your iron. also its surface tension isnt as good so you need a bit of flux in certain situations

Im replacing the capacitors in a speaker crossover.
The inductors and ceramic resistors dont go bad right?

>>2576042
bridge between the 2nd and 3rd pin from the top.
>>2576043
what's the point of using solder paste instead of regular solder in this scenario?

>>2576043

>>2576049
>what's the point of using solder paste instead of regular solder in this scenario?

Maybe it's handier than having to flux and solder separately

>>2575881
Yeah it has to be a spinning chopper disk with only one sensor. This is the lens.

>>2576011
what accuracy? NTC's have something like 3% per C change, should be easy to track with analogg inputs

>>2576049
not needing 3 hands

>>2576081
>Maybe it's handier than having to flux and solder separately
Which he did after tacking the corners. The solder paste is an added step.
>not needing 3 hands
Load the tip of the iron with solder and touch it to the fluxed pins/pads. Then drag solder the rest.

>>2575977
I'm the retard who tries to build a tone control.
How would I go about measuring this? Does picrel make any fucking sense? It's supposed to be a sinewave at 1khz

>>2576101
*I mean this is what happens when I turn the bass and treble pots

trying to "personalize" a totally legally-obtained söy scooter. pretty stumped at this

>>2576101
No if you put sine in you should get sine out (at different amplitude + different phase relative to input). Anything else is distortion. Make sure you're not overdriving the circuit. At max pot range it can amplify the input by about 15dB which is 5.66 and if you put 1V in you will get 5.66V out in those specific frequency ranges.

>>2576124
What's the goal?

I passed out randomly the other night. Never happened before in my life.
ECG just showed up strange and I've to go to A&E.
Hopefully all the zaps I've gotten over the years haven't fucked me up too bad

>>2576127
Oh now, that you're mentioning it. I think I had the function gen set to almost to max - so around 15v in. No wonder it's distorting...

>>2576164
>A&E
Arts and entertainment?

NEW THREAD
>>2575936
>>2575936
>>2575936

What does this convention mean? I see it a lot. Why do all of these wires merge together? Are they actually connected? Or it just means that it is some kind of a connector and a cable and I need to trace it and find the matching labels on the other end?

>>2576419
>Are they actually connected?

no

>>Or it just means that it is some kind of a connector and a cable and I need to trace it and find the matching labels on the other end?

yes

>>2576337
There used to be an autist who would have an aneurism if you made the new thread before this one was about to exit the catalog...

>>2576427
whoops. seems like I replied to a most unusual post.

So how fast will the bulb turn on in the Veritassium example?

>>2576419
That / means they are joining a bus. Each connector is independent but the entire bus is going to the same places in the schematic and on the board.

>>2576419
That / means they are joining a bus. Each connector is independent but the entire bus is going to the same places in the schematic and on the board.

I'd like to add a backup battery to an old Sony Dream Machine alarm clock. I looked at the schematic, and it has one single integrated controller with several VDD inputs (AVDD, DVDD, and some other). I also found a service manual for a newer model with integerated battery backup but it looks like the controller itself has support for it as it has a dedicated pin for that. So I was wondering if a crude approach of retrofitting a battery is even possible.

>>2576427
You mean me? I'm still here. Having a new thread before the old one gets archived sucks, because now you have to keep two threads open, or you could miss a reply.

>>2576468
>backup battery to an old Sony Dream Machine alarm clock.

$2 battery powered clock from the thrift store, with pleasant musical alarm sound, and changing-color LED back-light.
this is the kind of zero-effort, low-cost battery backup you need.

I bought this fire alarm second hand and I can’t see anything on the board that looks like it’d make noise (pic related). I’m starting to think I may have just bought the strobe without a horn: is this possible?
I’ve never installed a fire alarm before so I don’t know if it’s commonplace to sell the strobe separately. The reason I bought it in the first place was for the sound.
Sticker on the assembly says it’s a wheelock 3303; I also found a patent filing based on another sticker I found on the assembly:
https://patents.justia.com/patent/5608375

>>2576518
>is this possible?

they make doorbells and alarms for the deaf that flash instead of toot.
and some also vibrate, for the kinky deaf.

>>2576164
>all the zaps I've gotten over the years
no bro it's the govid vax

>>2576337
lmao

>>2576518
Got a wiring diagram for it? Or do you at least know how many wires can go in/out of it?

>>2576599
Just two terminals (PCB is behind the not-so-scary warranty sticker), which leads me to believe it's meant to connect to some "core" that regulates a larger network of them.

>>2576611
>signaling appliance and equipment for the hearing impaired
>visual signal appliance fire alarm
No ahoooooooooga's for you.

>>2576617
>>2576611
kek this shit is pretty funny.
you will have to wake up and open your eyes to see the visual alarm. you could run a wire to your bed to send a high voltage pulse to wake you up.

bring it back, tyrone.

>>2576434
You need to define what turn on means more precisely. 90% of the final value? 10%? Settling time? 1 electron going through lamp?

>>2576127
>>2576186
Fug. How do I adjust the voltage on that function generator?
t. retard

>>2576753
the dial called "amplitude"

>>2576549
Never got the vax fortunately.
Xrays and ct scans and bloods all came back good though so looks like It'll take a few more shocks to kill me

>>2576760
It works now, amplitude looks clean now.

Unfortunately though, hooking up my phone on the input and 60 Ohm headphones on the output, it is too quiet.

Would this also translate into the input of a linear audio amp IC?

>>2576812
Sir, could I improve it by adding a second op amp? Pls response
https://www.circuitstoday.com/passive-tone-control-circuit

>>2576819
Sirs?

>>2576819
Sir, you just need buffer on the output sir. Then the output power will be very very large and your music will be very loud heard all the way from Bombay to Delhi.

>>2576643
>you could run a wire to your bed to send a high voltage pulse to wake you up.
MyPillow 3.0

>>2576786
>Never got the vax fortunately.

Can you show some of your pcb projects, I need inspiration.

>>2576871
This is a picture of my bar mitzvah. I didn't want to pay the photographer for the pic so I just saved the watermarked pic. If you look closely you can see a motherboard.

Why do you need converters and transformers if the voltage can be lowered with resistors?

>>2576889
Time is cruel. Change is unavoidable. Death is inevitable.

>>2576889
Resistor dividers only really work if you're not pulling any current to anywhere else.
They keep the voltage stable across them if current is only flowing through them

>>2576889
Resistors turn the excess voltage into heat. Transformers turn the excess voltage into current.

>>2576518
light a fire under it and find out

>>2576856
Dear sir. There is already OP Amp on the input of the Baxandall. What is the reasoning for the "buffer"?
Is this nessecary for Amplifier IC? 60Ohm Headphone was only for test.
Pls understand, dear sir.

What happens if I try to start and induction motor on a current limiting light bulb?

No load on the motor.

>>2576011
What's your exact application? Does the sensor need to be reporting values digitally (SPI,I2C, USB, etc) or is it okay if the sensor reports an analog value that is sampled through an ADC? What is the temperature range you need? What about speed? Is this a temperature that varies quickly, or is it something like just monitoring the room temperature? You want a temp sensor that is in a SMD/TH package, or do you want some kind of thermocouple with long wires? You should also try digikey's parametric search with all your requirements.

just realised my shoe brand is "asics"

>>2576995
you need an output buffer, the output impedance of your filter is way too high to drive headphones with any loudness

>>2576996
might stall, might run, give it a try.

>>2576011
I2C controlled sensors tend to come factory calibrated.
Anyone knows the best temperature sensors, that are calibrated to high absolute and relative accuracy?

>>2577029
I have to add, if you can calibrate temperature sensors yourself (you probably can't), it's an entirely different game.

the fuk? thermistors have 150C cap and 18b20 only fucking 125C? what is this gay shit i need to measure temperatures up to 200C, how the fuck do ovens and shit do it then

>>2577030
Distilled water ice bath will come very close to 0°C. If you do a bit of research you can get it to within 0.002°C. Even with crude setup achieving 0.1°C is completely doable.

>>2577041
I tried it myself. It's not as easy as you make it sound.

>>2577043
If you don't need more than 0.5°C absolute accuracy, boiling method is a bit easier. The question is do you actually need the accuracy to justify calibration?

>>2577038
k-type thermocouple

>>2577038
Thermocouples

>>2577049
I just want highest resolution (at least 0.5°C absolute) for the least effort.

>>2577038
Thermocouples

>>2577038
Thermocouples, but K-types don’t give better than +/-2 degrees C. Look at other thermocouples (maybe 4-wire sensing idk) or go for a platinum RTD. Get a quality dedicated amp+ADC IC for it too.

>>2577055
I guess you need both precision and accuracy?

>>2577232
>I guess you need both precision and accuracy?
Yes. I want the real temperature.

>>2577233
Yeah then I’d go for a 4-wire PT100 or PT1000, and one of these:
https://www.analog.com/media/en/technical-documentation/data-sheets/max31865.pdf
0.03deg resolution, 0.5deg accuracy. Might be able to get better. There are dev boards for a few dollars on AliExpress, but I wouldn’t trust them if you really care about accuracy.

>>2577240
Most seem to do that well, like the BME280, which has the temperature sensor integrated, and comes factors calibrated. I've put multiple sensors (different vendors, all factory calibrated and all claiming about the same absolute accuracy) in one place and still got different readings.

>>2575936
I posted a few weeks ago about a failing gas furnace control board. After loading up the parts cannon and replacing the filter caps and replacing the 7805 regulator with a switch mode type, I was finely able to observe the fault. The relays would start clicking on and off at around 1-2 times a second along with the diagnostic and status LED. I got my multi-meter and started probing and found the output of a diode that should have been around 30 volts was 13 volts. I jumpered the failing diode with a 1n4007 from my junk box and the fault disappeared.

failing diode part number is RL104, will a 1N4007 work in it's place?

>>2577260
never mind, the datasheet recommends using a 1N400x series for replacement.

https://datasheetspdf.com/pdf-file/1200129/Diodes/RL104/1

Occasionally I've noticed a weird phenomenon when working on electrical issues on cars. For example, I'm working on a VW Routan (Dodge Grand Caravan) that had a no-start issue. I found that it was not consistently firing the ignition coils. One would fire consistently. A couple others were intermittent. The rest had nothing. After testing all the other components the computer relies on for ignition timing, I sent the computer module, which directly controls the ignition coils, off to be checked out. It passes all tests, all functions work, they send it back. I repeat my tests and we still have the same problem. So now the last thing I can check is the integrity of the wiring between the computer and the coils. I unearth all the wiring, visually inspect it, and ohm everything out between the computer connector and coil connectors. Everything looks perfect, excellent continuity, no issues with the wiring. Plug it all back up, and now everything is working 100% consistently. No repair action taken, only testing.

This kind of thing has happened at least a dozen times in my career. A consistently-failing electrical component or system mysteriously begins working only after the circuitry is thoroughly tested with no problems found. This is after conventional "resets" like removing the battery overnight or unplugging the malfunctioning component fail to produce any changes.

Is there a name for this or a known mechanism behind this kind of situation? I am not educated, I'm just a simple car fixer redneck who happens to know how to use a DMM better than the other rednecks in the shop.

>>2577272
> a name for this or a known mechanism behind this kind of situation?
it's called "Have you tried turning it off and back on again"

>>2577272
A socket/plug vibrated loose and you fixed it by disconnecting and reconnecting it.

Can I cut the 5v line in an usb cable to use it to transfer data without the possibility of drawing power from it? I have an arduino nano that I will be powering from the 5v pin, and as I understand it, powering the board from usb and the power pins at the same time is a big no-no.

>>2577301
No that's just fine. It won't draw power over USB if it has vcc

>>2577303
or vice versa. I don't remember which. Either way no one cuts their cables.

>>2577272
I have repaired a bunch of mid 90's Jeep ECU's every single one had failing caps that would cause intermittent issues, I have a ZJ ECU that has 300k miles on it, caps were perfect but when I went to change them anyway I found that vibration caused the solder joints to loosen up around the capacitor leads, pretty sure that caused a pretty inconvenient random stall and no start issue. Other ECU's had holes eroded in the capacitor cans but the ECU would still power on and run well enough for me to dump the EPROM out. The expected data retention of EPROM's is about 20 years, but they just don't fail all at once, all it would take is for access times to some of the EPROM cells to become inconsistent or erratic to cause a misfire.

My furnace would only glitch out every 5-7 days and it's been running with the failing diode still in place for the last few hours, what a strange fault.

>>2577295
This makes sense when plugs are corroded, burnt, or mechanically worn/damaged, and I have experienced that. What I'm referring to is cases where the connections have already been unplugged/replugged/wiggled several times without any change in symptoms, and the system only resumes function after every individual part of the system is tested with a meter. And then it continues to work reliably even after wiggling the connections, test driving, etc.

>>2577301
Look at the datasheet of your arduino, they usually have diode (or mosfet diode) circuits to prevent backflowing current. At least they basically always do so on USB.

>>2577272
>So now the last thing I can check is the integrity of the wiring between the computer and the coils
>Plug it all back up, and now everything is working 100% consistently.
It's either the wiring harness or the solder joints on the ECU board.

>>2577027
But will I need a buffer to drive an amplifier?
The input impedance of the the amp is very high, so I shouldn't need a buffer for that do I?

Is pic related what you mean by "output buffer"?
https://www.allaboutcircuits.com/technical-articles/how-to-buffer-an-op-amp-output-for-higher-current-part-1/

>>2577416
No you don't. Every amplifier is effectively a buffer with gain

The output buffer in your picrel just lets the opamp amplify more, like stacking two gains together. They have a limited current capacity compared to fatass FETs.

>>2577417
How's this one?
http://www.muzique.com/lab/buffers.htm

Probe is set to 1x.
This is all I get, with only the oscilloscope probe hooked up to the output of the tone control.
It just seems quiet, regardless of load. Am I wrong?

>>2575936
Not sure if this is the right thread to ask in, but it's my first time soldering and there is a bunch of this yellow stuff all over my PCB.
I'm assuming that's flux? What's the easiest way to get rid of it? Will it just evaporate if I heat it back up, or should I use something like cleaning alcohol to scrub it off?
I really don't like the look of it and parts of the PCB are going to be exposed once I'm done.

>>2577453
>I'm assuming that's flux?
Yes
>should I use something like cleaning alcohol to scrub it off?
It's most propably rosin residue which is completely harmless. The only reason you might want to remove it is in fact for cosmetic reasons.
And yes, isopropyl alcohol works best. If you have an ESD safe brush, use it to rub it off in combination with alcohol or if there aren't any susceptible components, just use a toothbrush.

>>2577452
>Am I wrong?

you're a noob so the answer to that questions is always gonna be yes.
pedals typ operate at AUX levels, which is, by convention, around 0.1Vrms
your scope is showing 500mV but we dont know how it's set up, so that could be RMS or peak or peak-to-peak.
so, 0.5Vrms would be a tad high, but not so huge it's fatal.
if it's 0.5Vp-p, that's 0.17Vrms which is acceptable.

>>2577453
>easiest way to get rid of it?

easiest is to leave it alone.
spend the time you'd need to clean it to work on your autism instead.
if you cant overcome your cranial anomalies, alcohol and a toothbrush will fix the board.
(this comment might lead to another existential crises: do i use 50% alcohol, 75% or 99%? which one is RIGHT? the answer to that is YES.)

>>2577453
Cleaning alcohol (preferably like 99%) with a toothbrush and maybe a kimwipe is the way to go. That flux residue is almost completely harmless, but it is sticky and probably mildly corrosive. I wouldn't really worry about corrosion unless it's a project meant to last 20+ years, or 5+ years in a particularly humid environment. Those are just bullshit ballparks, take them with a grain of RMA.

>>2577460
>your scope is showing 500mV but we dont know how it's set up
It's a CRT (maybe a hybrid digital) scope, there probably won't be any dynamic amplitude measurement, and there aren't any cursors on the screen. That will just be the V/div, same how the "T:500µs" is the time/div. So that would mean 1.3Vpk-pk, or 0.46Vrms.

I think the "PT:50%" and "DC:27.5mV" are part of an internal function generator. I suspect the anon is just feeding the sine out of the scope, into his tone circuit, and back into the scope. So the total amplitude doesn't matter so long as he stays away from clipping and the total gain is sensible.

>>2577452
Hey plot both the before and after waveforms on the scope. All the tone should do is change the amplitude (and phase somewhat) as a function of frequency, you'd be able to see that as you sweep the frequency across the human hearing range. It would be easier to see with a wave that isn't a sine-wave, like a square or sawtooth. You'd see the sharp corners get taken off a ~500Hz wave by the low-pass functionality, and just the sharp corners left behind off a 20Hz wave by any high-pass functionality.

>>2577272
>Plug it all back up
Reseating all the connectors should have been your 2nd step, after running the diag software.. It's not a rare issue. A plug doesn't have to be visibly fucked up to be marginal. Back in the day Centronics plugs on printers regularly had to be unplugged and plugged back in or they stopped working. My father has had a problem with his monitor a few times. I told him to unplug and plug it back in and it worked.

>>2577490
>unplug and plug it back in and it worked.

unless you give it a spritz of this, the problem is just gonna come back in a few weeks.
(seems WD-40 is now offering a contact cleaner as well; tho oddly price seems to vary from $7 to $23 from place to place for 11oz.)

>>2577482
>I suspect the anon is just feeding the sine out of the scope, into his tone circuit, and back into the scope
No, I am using the aux of a phone to input the signal into the tone control and am measuring the output of the circuit.

I don't know what that 27mV and 50% is.

But the other anon was right, that the voltage per division is around 500mV.

>>2577460
It's not a pedal though. It's an amplifier.
I also hooked it up to an amp circuit and am getting around 2v out of it.

What did I do wrong, Key Cat?

>>2577496
Did you add edge cuts?

>>2577482
>Hey plot both the before and after waveforms
The square wave is completely scuffed for some reason

>>2577482

>>2577507

your scope has 2 channels.
you're supposed to use that to show in/out in a single pic.
doesnt matter if you only have one probe.
use a thick paper clip (or a nail) and a wire as a probe.

>>2577514
OK. I will do that next time. But I think the picture shows indeed that the circuit is amplifying.

>>2577504
No, I didn't.
Thanks Anon!

>>2577504
Is this a severe error?

>>2577530
fixed it :^)

>>2577531
btw. this is an excellent introduction to KiCAD https://hackaday.com/2016/12/23/creating-a-pcb-in-everything-kicad-part-3/

Here is the real electronics, ASIC design
https://youtu.be/69mdJv6fWXE

It's my first PCB

>>2577533
>watch later :^)

>>2577543
Fair play.
Make sure you check everything well before getting it made.
My first PCB I used the wrong footprint for a MOSFET so the source and drain were in the wrong place and my 2nd one I wired all my pots back to front in the schematic so turning the pots counterclockwise turned them up and vise versa.

You don't need any holes to mount the board?
Or decoupling caps for whatever U1 is?

>>2577644
Good thing where I'm "working" there's a CNC mill where I can have everything made FOR FREE.
So it's not that fatal if I mess something up.

>You don't need any holes to mount the board?
Thanks. I'll add that.
>decoupling caps for whatever U1 is?
It's a NAND gate.
There are two caps. I have the upper layer make a common VCC and lower layer GND. So they are connected directly to that.

>>2577675
Are the capacitors specifically for decoupling the power for the IC or they're for something else in the circuit?
Generally you put a capacitor specifically to decouple the power on every IC on the board (100n ceramic capacitor as a rule of thumb) and good design practice is to have it right beside the power pin of the IC

>>2576434
Veritassium's description of the problem is misleading. The keep point is "any current." So one electron being moved by the electromagnetic field is going to qualify and "turn the lamp on." This of course doesn't apply in the real world. One electron isn't going to turn a lamp on in any meaningful sense. Nor is a handful of electrons.

AlphaPhoenix actually tested the experiment. The graphs at 18m07s should clear up what Veritassium failed to explain. https://www.youtube.com/watch?v=2Vrhk5OjBP8

PS2 gameconsoles sometimes have bad video output and these arrays of resistors tend to be the culprit.

I can't find where I can cheaply order the part. I don't know how proprietary resistor networks can be? The part number is 1-234-710-21 and the description is "Resistor Chip Network 47x8". I think the 47 means that many ohms. Could I find an identical part without paying a ton for the Sony part that probably is out of production?

This was talked about in a recent Louis Rossmann repair video. In the video (and the one his is based off) both fix the issue by bridging the points with wire and the video is fixed, but I don't think that's safe for the console longterm.

>>2577781
It's 8 separate 47 ohm resistors in one package.
The case size seems to be metric 3816 which is a bit longer than metric 3216 (standard 1206)

You'd probably get away with soldering a 1206 one on there no bother

>>2577759
I watched veritassium’s video, and the sad backpeddling video. The whole thing is a stunt/trick for clickbait.
He also implies and confuses mathematical tools used for computing field strengths is actually how (and fully explains) reality works, which is ludicrous (esp. if you’re into semiconductor physics)
Anyway, what happens is that you’ll see a small induced voltage in the wire almost immediately due to magnetic (inductive) and electric field (capacitive) coupling.
The whole earth scale thing was just a bunch of misdirection.

>>2576043
Just get a robot to do it at that point

>>2576164
You probably have type 2 diabetes

>>2577781
> resistor network failing
Sounds like the were fragile enough to get blown by static discharge. Just find the one that is bad, stick (glue) a small smd on top of it, and wire it on the leads.

But yeah, 47 ohms isn’t a high value, prob fine if bridged, probably has protection on the source and dest anyway.

Not sure if this should go here or in /mcg/, but when should a microcontrollers DAC be used instead of PWM + low pass filter? Is it just a way to save two components on the BOM?

>>2577865
PWM + low pass filter can be annoying if you want low noise and quick changes. How do DAC outputs usually work on MC's, R2R ladders?

>>2577871
For my purposes, low enough voltage ripple and fast enough response can be had easily with 100k and 100nF and a frequency of 1 Mhz

>Four 12 bit DAC channels (2 external buffered and 2 internal unbuffered) can be used to
convert digital signals into analog voltage signal outputs. The chosen design structure is
composed of integrated resistor strings and an amplifier in inverting configuration.

>>2577878
if it has R2R DAC's just use those then. Setting up PWM sounds like more headache than it's worth.

>>2577865
PWM+filter can be accurate and fast when you put an aggressive enough low-pass filter on it. You could probably get 16 bits of resolution with enough filtration, nonlinearities notwithstanding. You often need to buffer the output anyhow, so I’d recommend using a 2-pole sallen-key filter in that case to kill two birds with one stone. If you don’t need to buffer them and are fine with the response time being orders of magnitude lower than the PWM frequency, PWM with a passive output filter is perfectly fine. You can stack passive filters if output impedance REALLY doesn’t matter, say if you’re driving the FET of a variable load.
It’s an especially useful technique when you need a lot of analogue outputs, or when you’re trying to cut down costs by using an MCU without a DAC.

>>2577881
From my experience with AVRs, the DAC is usually a bit easier than setting up the timer, but not hugely so. More pressingly, often you want to use that timer for something else.

"GreatScott" seems to have good videos but I cannot listen to him for longer than 10 seconds.

>>2577910
Agreed, being ESL is not an excuse for his faggot retard diction

>>2577928
exactly, i get it he pwobably has a speech impediment on top of the accent as he cannot pwonounce the R sound and that's annoying as fuck but he can't help it. but he also needs to dwop that pwetentious cadence, gosh. maximum cwinge.

>>2577781
find the bad resistor pin, if it's open-circuited, add a 47ohm across it, if it's shorted, desolder and lift the affected pin and break it off, then solder a 47ohm across it again. repeat for all bad pins.

>>2577675
*NOT Gate
>>2577696
Yes, I'll rearrange them closer to the power pin.

>>2575936
Where can I get 18650s that actually work? Apparently the Epoch cells I got were dead on arrival, and I need to make sure if I'm going to buy something a second time, it will actually work worth a damn

>>2577507
Looks like the gain is way too high for high frequencies, those spikes are 20 times higher than you'd expect. Maybe there's a capacitor in parallel with the ground resistance (non-inverting) or input resistance (inverting)? Does it change when you adjust the treble pot?

That or it's not stable with fast edges and is oscillating.

>>2577508
Post a schematic instead.

>>2577859
>blown by static discharge
Across a 47Ω resistor? No way man, impedance matching would result in all the heat going into whatever is in series with the ESD. Bet it's just cracking under flexing or thermal deformation.

>>2577910
I can stand him more than that ESL who puts an inflective emphasis on the end of every damn sentence.

>>2577960
2nd hand cells from laptop banks from local sellers is never a terrible way to go, but you're not getting top quality. As for new name-brand cells, try services that make/sell e-bike batteries.

>>2577950
>desolder
what's /ohm/'s opinion on cutting a track with a razor, scraping away some solder mask, and soldering the resistor directly to it?

>>2575977
What the fuck is rt?
A flux resistor??

>>2577973
not uncommon

>>2577507
Does this look fine, anon?
See, the scale is 500mv per division for all, except for the square wave where it's going completely out of spec for some reason.

>>2577973
Fine if it's the only way to fix it. I don't think you need to cut the trace in this instance though. Desoldering might be a pain if you don't have the tools, but I've done SOICs using a piece of solid-core copper wire bent across both rows of pins to reflow them all at once. Soldering an SMD resistor on top of the burnt out one also works.

>>2577973
My opinion is to not destroy the PCB if you don't have to. I am also pretty sure you can find a part like that on digikey for a few pennies, you could replace it with an equivalent and not have a fucked up ps2 board.

>>2577991
>for a few pennies,

>Shipping is $12.99
>They flat out refuse to just throw it in an envelope with a $00.25 stamp even though the only way it'll break in shipping is if they steamroll it

>>2577696
There's a ceramic and an electrolytic cap that are both connected from GND to VCC.
I put the ceramic cap right beside the power pins of the IC and left the electrolytic where it is.

>>2577696

>>2578005
>KiCAD Menu
>Plugin and Content Manager
>Repository
>Plugins
>Round Tracks
>Install
thank me later

>>2578012
We 1970 now

>>2576011
thermocouple

>>2577979
Anon?

>>2578012
>install button is greyed out

>>2577910
Let's get started.

>>2577910
I'd need subtitles to understand him properly.

>>2577910
>>2577963
>>2578117
What about Robert Feranec?

Are there any controls techs/engies here

Anyone design circuit boards for a living? What was your education and prior experience to get that job?

Ive worked on electronics without a degree for 15 years, but recently mangled my hands, and always wanted to do PCB design.

>>2577460
most flux is corrosive

>>2577910
That's why you have to watch Marco Reps instead.
https://www.youtube.com/watch?v=mmsBT3Fuggk&t=299s

>>2578119
Tolerable

can you guys help this brainlet on how to read this. I want to figure out where viewing area (red cornered rectangle) position. So I want to calculate blue lines. Left, Right, Bottom and Top

I think left and right is 3mm because Right is marked as 3mm (follow arrow). Since total width is 42.72 (at top), viewing area is 36.72 so left also must be 3mm

But I have no idea for top and bottom. Help please

>>2577910
>>2577928
>>2577963
You are weak

>>2578206
I found more schematics and I think I figured it out (bottom is 8.26 + 10.41 and top is 3.03 + leftovers)

>>2577974
A potentiometer. RT = Resistance Treble.

>>2578222
Oh shit I feel retarded, thanks
The blocky resistor threw me off, schematic symbol is squiggly and I would have recognized it instantly

>>2577963
>I can stand him more than that ESL who puts an inflective emphasis on the end of every damn sentence.
that sounds exactly like him. unless i confuse him with someone else. which channel are you referring to?

>>2578103
Inorder to be that level of boomer you have to pay your taxes and write no less than 3 essays praising Israel OR comply with 16 unlawful orders by public officials.

>>2578242
That's a Euro way of draw schematics.

>>2578274
What's the name of this standard?

>>2578299
IEC or something?

Seems like false advertising to call it 14-stage

Ok, I found a tube preamp for a guitar cabinet under my bed. Some years ago I disassembled it in order to fix, even bought some new switches and unsoldered old ones, but then life happened I forgot about its existence. I had photos of the connections on my old phone, those are long gone.

How can I fix it if there's no schematic? What would be your procedure if someone came to your cave, asked to do it and payed lots of money?

The preamp is valuable in sence it's somewhat unique and not sold for decades, so I'd like to fix it.

>>2578349
Dust it off with a paintbrush and vacuum it. Clean all of the pots, jacks and switches with contact cleaner. Reflow all of the solder joints. Replace all of the electrolytic caps. Clean the tube sockets and pins.

>>2578352
But I don't know where those broken/unsoldered wires go anymore. I removed some of the switches and some wires broke because it was all dangly and weak.

>>2578353
Well you need to find a schematic or start mapping it out yourself. What's the make and model?

>>2578166
Really like this guy.

>>2578244
Nah Scott is like an oxford graduate in comparison, this inflection was REALLY bad. Can't remember his name now though, I thought it was Electronoobs but after checking it definitely isn't.

>>2578337
It is, it just doesn't present all of its outputs. The output is 2^14 times lower frequency than the input (I think), it only presents the outputs considered useful for its purpose (stepping down a 32.768kHz crystal).

>>2578356
Oh fuck, I'm a total noob in electronics, I can solder but not develop... I bought it used in mid 2000s, it's a BMT TubeWizard from Ukraine, there's no way schematics exist for the thing. I will try to contact the manufacturer, but I have little chances of success.

In the meantime can you suggest youtube tutorial how to reverse engineer a pcb?

>>2578369
I don't know any youtube reverse engineering tutorials, anon. Sorry. Here's some pics though:
https://guitarplayer.ru/equipment-craft/tube-wizard-budem-modit/15/

>>2578368
I'm sure it has 14 stages but users would never be able to tell if it only had 13, would they?

>>2578368
>it just doesn't present all of its outputs
That still sounds like a fraud

>>2578374
>>2578368
Oh nevermind, what they call Q13 is actually the same as what every other manufacturer calls Q14

>>2578380
Who the hell start counting at 1?

>>2578384
Zero-child policy doesn't have the same ring to it.

>>2577992
> steamroll it.

I can assure you that shipping/import/customs companies encourage employees to steamroll, bend, spindle, mutilate, up end, crush, kick, puncture, immerse, loose, discard and steal packages that are not tracked, registered with “premium” options.

It actually costs, say, amazon *more* money to artificially delay cheaper non “next day shipping options rather than just send it out asap as is their normal process.

The last thing I actually received in unregistered normal mail as an old nintendo cartridge. This was within my own country, i convinced the ebay seller just to do that… at least 15 years ago. I’ve received ZERO things from hobby king, for example that went by untracked mail, and I’m pretty sure for other things, the actual postman stole them because I know it got here.

Not paying $12 shipping on a 50 cent amass connector.

>>2578299
> rectangle resistors, name of standard is IEC
No, it’s called “wrong” doesn't need any other name.
Don’t draw them that way.

>>2578299
The story has it that it was the French who came up with that symbol since they are really bad at resistance.

>>2578403
Heh, but in reality I think it's just german autism. My german power electronics professor is the only person in Yurop I've met who uses these symbols

I just started reversing the schematic from here >>2578349 and already got stomped. WTF IS THIS??? How is this possible?

>>2578384
You can't begin soldering at pin null god damn it

Hello /ohm/, /3dpg/ tourist here.
First, what's the point of these big fuses in pic related? As most boards seem to do well enough without burning down your house these days, are they even necessary?
Second, considering every driver breakout board comes with a potentiometer to adjust to your motors, how do these kinds of board without potentiometers work? Do they just kinda average the reference, or is in this example Prusa basically locking everyone into their specific LDO motors?
Last, but not least, given there's 1 driver for two (z) motors, doesn't that mean that particular driver is stressed far more than the others or is there some kind of duplicating magic going on here?
If haven't already, please do assume me a moron. I'm just trying to finally catch up on electronics and see if i can make some sense out of my prusa in comparison to other machines.

>>2578388
That's what I can call it
Like they made schematics in Ms paint

>>2578403
Fucking kek

>>2578418
> bigass car fuses
They are avalable everywhere, dirt cheap, standard, and low voltage. And pretty colors. Cars have a bunch of similar motors and solenoids on them too.
Cheap insurance incase the output driver goes into oscillation in case this is some kind of “open source” project put forth by a tard.

>>2578418
>fuses
firstly its the last line of defence. if something goes massively wrong and the circuit is overloaded or short circuited, the fuse will blow and cut the power before anything else gets damaged. secondly, regulation. to sell commercial products, especially cucked nations like europe or australia you need to get regulation and having fuses is part of that.

>how do they work they work without pots
see that massive chip in the middle of the board. it controls the 4 motor drivers on the bottom. it is usually done this way too. breakout boards for stepper motos with pots are a special case because either a. the driver chip allowes analog input or b. the analog input is converted to something else the driver chip recognises

>kinda average the reference, or is in this example Prusa basically locking everyone into their specific LDO motors
i have no idea what youre trying to say here.
those 4 things at the bottom are stepper motor drivers. steppers are 2 phase motors that need a special setup to rotste. the driver chip works by carefully switching the 2 phases on/off for each of the motors to make them rotate a specific direction and speed. this is translated usually from a PWM signal coming from the big chip (microcontroller).

>z motor
its likely got 2 outputs on one driver chip but runs in parallel. so it wont be stressed if this is the case. if not then its in direct parallel so the answer im becomes maybe. get a DMM and probe the 2 z motor headers and see if all the pins are connected. even so, if the driver chip is rated to run at or more than the power required for each motor, then it will still be fine for many years. its actually probably better to have 2 z motors because the build plate is heavy

3D printing motor control systems are pretty complex for someone who knows nothing about electronics. ive glossed over a lot of the details but basically...
>big chip control small chip control big motor
>fuse stop explodey things

>>2578388
That’s not that bad, look at what the IEC tried to do with logic symbols.

I mean, that is actual criminal retardation. All the people that developed that are now working on the IEC standard for the 53 different sexuality pronouns.

Well, thank god it went nowhere, or if it did go somewhere, it and everything else connected to it can be safely ignored.

How are you doing it, it's way too complicated and takes tons of time? That's 3 hours or so, just a small portion of scheme.

>>2578462
I think there might be a full bridge rectifier in there, but I can’t tell because it’s drawn in an obfuscated way

>>2578409
>How is this possible?

reason is you suck at tracing circuitry.

>>2578409
>How is this possible?

reason is you suck at tracing circuitry.


D1 to D4 should be drawn like this: https://www.falstad.com/circuit/circuitjs.html?ctz=CQAgzCAMB0l3BGEBOaB2AHGZyMBYBWMANgwCYEIy0QDbJaBTAWgQQCgA3ENYhgshh59wpKCCRl4DMBgbyo0AuwAqw-oJRiSQ+dDyK2R4ybaLiCDGgRoyeSGzzI2NZgWjECeNM6I+yJNSKOMjsACYoUiB4eELIYvYMZCBhjABmAIYArgA2AC7hWkKJEg7E0bEgyamZuQURyFExcQnxVSnp2fmF8cVtCGUVQtWddewA7kWiLcVwUBNTTuW9tJqQ7ABOEgMGzduQBgIKYAsDCOV7bAdD85ONDHv3tCLrd1EEIleHL6c7qwxfZ7ydgAYwkZDsNwQEO+ChgDiqeGglkwkDIREoMOur32sPBkI+wMmgJiAL+JRxJLm0PO0TmlIoF2pMLpRPxu3s7JuDMhJWhvM5lPJnJJlXWAHsQEIkA9IDg6eDoLp2kITpLKBJxHgLEhOeiPJrkhqTkA

D6,D7 should be drawn like this: https://www.falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l3BWK0wIBxgCwGYBsl8FcB2LHEATkhCXIQFMBaMMAKADdxNNxjcueAJiJRwIfOAqjqMBKwAmIQZmpgJ2QaomCQ8+gDMAhgFcANgBcFIDaoo7lt+7oMmLrAOYClIskuI6ZVgB3LzA+UIlIYIjqB3BI6Li1WJVJANZNKRtvfmywO2lYSAgwNGhMYmLBbEgKNEw0PEg0UTZM63qlZo6hf0K4ErLMXHrh3ARIGu5BAPAPa00chdi+wM9sTsE+jaE0FsCQvIKGxyhona6Wi+Szw86bvIS7nhuT+MCAJxBuFq2dH8uohmrC+2AQOjBEPBflmwMO0L+1mh+XSIQBmhaAJuUXW0MhSIhI2k83RfXRe2JeExaC01EwFH42LOVO+NLS3wZ7MCAHsuOIeHTalJFjB4LU+ERhEC+dhWEA

>>2578475
>>2578466
There's no full bridge rectifier... Maybe somewhere down the road, but not here so far. I do suck though, I've never done something like this before.

>>2578482
>There's no full bridge rectifier.

sure there is.
if you draw it right.
in both cases,
- one side of transformer goes to + of one diode and - of another
- other side of transformer does the same with 2 other diodes
- the 2 positive sides after the diodes join up and go to the + of cap
- the 2 negative sides after the diode join up and go to - of cap (ground)

in both drawings all connections match, so you have a FW rectifier.

>>2578493
> - one side of transformer goes to + of one diode and - of another
Yes.
> - other side of transformer does the same with 2 other diodes
No. Here's the picture I took of the 12.4V lines. As you can see both + and - get onto same diode polarity.

>>2578502
>Here's the picture

that picture 100% verifies my claim.
but dont sweat it, just keep on truckin'
you gotta lot of work to do.

>>2578418
>a potentiometer to adjust to your motors
That sets the current driven to the motor. Though I think some printer setups do that in software instead. Too low a current and the motor torque drops so you skip steps, too high a current and the motor and driver get too hot.

>doesn't that mean that particular driver is stressed far more than the others
Yes and no. If you were just driving constant-voltage square waves then yeah it would be outputting twice the current, and so would be getting twice as hot. But if you're running a driver with current control like an A4988 (read the datasheet if you're interested) the output current will be limited. In the case of running two stepper motors off one driver, if the current setpoint isn't changed, each motor will only get half the normal current, and hence only half the torque each. I imagine the current is set higher for those steppers.

I'll note that running multiple steppers off one driver is kinda shit. Better off just using one stepper and a belt between the two Z-screws. That way you can tune the levelling using some sort of idler system, instead of having to get it level solely using shims (or by ramming the bed into end-stops like that sovol).

>>2578502
bro that is a full bridge rectifier
and the ac lines aren't + or -, they're ac

>>2578388
OK, Boomer.

>>2578502
>As you can see both + and - get onto same diode polarity.
Look more closely, think abut the traces.
Top line: bottom of NE diode & top of SE
Bottom line: bottom of NW diode & top of SW

>>2578457
They made them look that way for a reason. It makes them much less ambiguous. Take the ANSI AND and OR as an example: if you draw those symbols by hand it doesn't take much to turn AND into OR if you don't draw curves in just a right way. With IEC it's impossible to mix them up.

>>2578630
>doesn't take much to turn AND into OR
Or is a concave slice of AND about 30% its width, so yes, it does

>>2578630
considering the scaling, i'd say it's at least as easy to turn ≥1 into =1

i mean cmon, those symbols on them aren't even the same as any symbols for the operations themselves. why ≥ and =?

>>2578636
>why ≥ and =?
It's actually a nice trick that extends functionality. You can have ≥2, ≥3 which mean output activates when 2 or more inputs are active. Same with =n, which activates output when exactly n inputs are active, this then has something to do with changing addition modulo, because XOR is addition mod 2. So yes, symbols do represent operations.

>>2578438
>in case this is some kind of “open source” project
I think it is?
https://reprap.org/wiki/Rambo_v1.2
It is the controller board of one of the most known "just werks" 3d printer, the prusa mk3s. As you assume it's made a retard, why is that so, any obvious flaws to see?

>>2578452
>fuses
>regulation
Guess that makes sense. Frankly i didn't think of comparing controller boards by heritage yet.

>kinda average the reference, or is in this example Prusa basically locking everyone into their specific LDO motors
>i have no idea what youre trying to say here.
First, to clarify, i call the potentiometer reference as that's what most more technical guides call it. Second, it makes more sense with the answer by >>2578614. Given LDO and Moons motors as example, you'll usually set reference lower for LDO and higher for Moons. As this option doesn't exist without reference, i was a bit confused how else this would be handled.

>>2578614
>Though I think some printer setups do that in software instead
Looks like it's really that simple, the exception being rather older 8bit main chips and offering a more hands down approach to tinkerers. Guess it was just too obvious.

what would happen if i used this thermistor rated for 150c to measure temps up to 250?
will it melt or something? i only need precision within 10C

>>2578636
The explanations for that are all written in the new universal language everyone speaks: esparanto, and typed on a dvorak keyboard, the layout everyone uses.

>>2578645
Glad they felt the need to “explain” how logic works in every single gate. Except for and, of course.
Why not use the symbols logicians have used for centuries so people will understand that?
The reason is that the developers of that IEC “standard” were likely uneducated and/or ignorant, and probably never heard of DeMorgan or Bool.

>>2578669
Standards evolve from practical experiences. You're looking at this from academic/theoretical perspective, but enough people in the industry had problems with old style symbols that they had to use something else. You're being unfair to IEC because you're only looking at fraction of basic functions, but the point of standard is to deal with much larger complexities. IEC logic symbols are an engineering tool capable of much greater abstraction.
https://www.ti.com/lit/ml/sdyz001a/sdyz001a.pdf

>>2578505
>>2578614
>>2578621
If it is a full bridge rectifier (ive marked it on the right side of the picture), then the outer line is GND or DC-. How 16.8VAC output from transformer (yellow lines marked on the left) simply connect to this DC- then? It's so fucking confusing.

>>2578657
>LDO
>moons
ive literally never heard anyone call a stepper motor this. are these brands or something? anyway reference may not be even set in software it might be some sort of zener diode to give the correct reference for each chip

I have a active low reset pin on a 3.3v ic that i need to control from a 5v output pin of an I/O-expander. The reset pin is internally pulled up to Vcc (3.3v) by a 30k-80k resistor. It needs to be kept low att startup and not let go until some other stuff boots up. After that it should be held high mostly. The expander has push pull outputs and at startup they are configured as high-z inputs. I dont know how fast they configure so i put a cap to make to input not go high by the pullup to 5v before the expander configures. And also a diode to shift from 5v to 3.3v. Will this work as intended or is there something i've overlooked? The reset pin has a max low input of 0.9 v

>>2578713
Yeah, those are brands. You'll see them a lot when looking for Voron 3d printers or mods in general.

>>2578718
lol better to use the type of motor to describe it because LDO is a term used when talking about voltage regulators

>>2578716
nmoswith the gate pulled up to 5V. at sysgem turn on the pull up will turn on fet thus keeping the pin low. when the gate is at 0 or low, the reset pin will be pulled high through its own pull up

>>2576025
Lead free solder is shit

>>2578778
did someone say ''shit''?

Lead free is like onions milk?

>>2578778
Enjoy your nerve damage

>>2576025
>>2578778
>>2578848
Which lead free solder is the best? I heard there are large differences, and the better ones are patented. Choosing the right one can't be trivial. I'm relatively content with Sn99.3CuNiGe, but I'm a casual.

my friend told me of an issue with a device design at his job. Evidently they're trying to run 3.3V i2c over 10 feet and it's experiencing noise issues.
Now I'm not very experienced but I still want to think of a way to fix it, for fun. Could a level shifter be used to step up the voltage of the i2c signal, and on the other end, step it back down to whatever it is it's transmitting to?

>>2578875
Yup.
>I2C level shifters, buffers and hubs strengthen your I2C bus signal and prevent heavy bus-capacitance loading.

>>2578875
With 10 feet of distance you need to be careful about how you do things because you're dealing with transmission lines. What you need to do is something like
https://www.nxp.com/docs/en/application-note/AN11075.pdf
Use standard CAT5e Ethernet cable and appropriate buffer. You can't just take any old cable and even if you change voltages it won't do much better. A proper setup like in app note should work up to 60 feet.

>>2578838
More like cactus in the ass.
It is really demanding of the iron

Here is some "mom im thermal engineer" stimulation of hakko 900M, hakko 900M + sleeve, hakkp t12

>>2578740
Now that's something i never heard of . Still a good read, these things seem pretty useful.

>>2578886
shit I didn't even think of that. I'm looking through that AN now.
Help me understand this: Given that i2c runs at 100-400 KHz (I don't believe the circuit is using any of the faster modes), that would imply that the wavelength is at most about 750 meters. Why is it that the 10 foot/3.04 meter cable acts as a transmission line for something with a wavelength of 750 meters?

>>2578884
based thank you

>>2577301
you can cut the line, just keep the ground intact but i don't think it's necessary, most products will place a diode to prevent current from flowing through the 5V usb node. I can't guarantee you that this is the case with the arduino since I don't have the schematics. Furthermore, if it's a chinese knockoff, all bets are off on what shortcuts they took and what parts they cut off from the design.

>>2578875
>i2c over 10 feet
Why.

>>2577530
the courtyard is outside of your edge, which if the edge is the dimension of the pcb would mean your diode would stick out to the side. As long as the hole/pad your diode is soldered to is not too close to the edge (how close, look at the PCB manufacturer specifications), you should be fine, but better to fix it to avoid nasty surprises.

>>2578909
because their EE is a moron who doesn't know his ass from a hole in the ground and I want to take his job

>>2578899
You need to forget about clock frequency and consider edges - that's where all the high frequency content is. Sure clock is 100kHz, but rise time is 1000ns in normal mode and anywhere from 20-100ns in fast mode (400kHz). Bandwidth required is equal to 0.35/rise time. For slow mode (up to 100kHz) its 350KHz, for fast it can be anywhere from 3.5 to 17.5MHz. As a rule of thumb, transmission line effects start to happen at 1/20 wavelength so for slow mode 43m, fast mode anywhere from 4.3m to 0.8m. Remember lumped element model holds for dimensions much smaller than wavelength, that much smaller is sometimes factor of 10 or 20, but at 1 wavelength you're already deep in transmission line territory.

>>2577992
go to an electronic shop next to your home then. I don't know where you live, but if you live in a major city, you'll probably have a few of those. Alternatively, try aliexpress if you're willing to wait for 3 months for the parts to show up.

>>2578403
topkek

>>2578741
>nmoswith the gate pulled up to 5V. at sysgem turn on

Do you mean the expander output? It says its high z at reset. I guess the problem is that i want to have a default pulldown of both the reset pin and the expander output at startup, or somehow make it so that the high z expander output doesnet pull the reset pin high. I've come up with pic related. the problem is that the voltage on the reset pin i the ce voltagedrop which equals be voltage drop, and it feels dangerously close to the max input low of 0.9v of the reset pin

>>2578663
Likely loses its linearity past that so you'd need to calibrate it with your own lookup table, may also not go back to the same resistance after cooling down. May burn.

>>2578697
>then the outer line is GND or DC-
GND specifically. DC- has a somewhat different implication. By tying one pin of the 16.8VAC winding directly to GND, they can use a half-wave rectifier to get a DC voltage. Why use a half-wave rectifier even though the ripple is worse? Because you can use one twice, one for a positive rail and one for a negative rail. See >>2578462, D6 makes a +16.8V rail, while D7 makes a -16.8V rail, both referenced to GND. Hence C5 being the other way around from all the other caps. Pic related is how I'd draw it, positive rails above ground and negative rails below it.
Also D5 might be a zener diode, see if you can read its value.

>>2578852
The 99% tin stuff is just a pain to work with, doesn't flow nearly as nicely as leaded. But bismuth solder on the other hand, that's the real good stuff. You can get alloys that melt as low if not lower than leaded solder, and it flows nicely. Was using it for a year without knowing it had bismuth, got a rude surprise when I realised normal 99%Sn stuff doesn't act the same, and when I realised LCSC stopped selling rolls of solder so I can't tack on another roll to my order.

>>2578916
>Bandwidth required is equal to 0.35/rise time
interdasting

>>2576032
Well, 440C in my case.
>>2578778
yeah
>>2578852
Sn95/Sb5
Because this is the shit you use for plumbing.

>>2578940
This is what the other guy was implying. There will be a very low voltage drop across the MOSFET while it's turned on, which will be the default while the logic buffer isn't active.

Your image there would always have a 0.6V drop across the PNP, and a further 0.6V drop across the diode, so it wouldn't get lower than 1.2V or so. If you ditched the 10k pullup and the diode, and replaced the PNP+pulldown with an NPN+pullup+base_resistor, then you'd only have the collector-emitter saturation voltage of 0.3V or so between the reset pin and ground.

mmmm are you sure about that babygirl

>>2578960
>lead near plumbing for fresh water supply
Sure, ingesting more lead will make you immune to lead. But how is this related to electronics soldering?

>>2578663
those are NTC thermistors. They are usually used to limit inrush current, where initially when they are cold, they have high resistance, and as current flows through, they heat up and turn into short circuits. I don't think they are great as temperature sensors since as things heat up, they end up becoming more conductive, which means more current and more heat, i.e. thermal runaway. So if you're going to use those as a temperature sensor, make sure that you limit the current through them with an actual resistor in series. Furthermore, their temp vs resistance curve is non-linear, so you have to compensate for that in your software. There is a way apparently to linear it somewhat, read this:
https://electronics.stackexchange.com/questions/8754/how-to-measure-temperature-using-a-ntc-thermistor

Finally, operating them at above the specified temperature might or might not destroy them, but if it doesn't, then you will most likely get garbage data that is extremely inaccurate due to the curve flattening out (even for +/-10C accuracy). In this specific case, the operating range is up to 125C, not 150C, that's only for short periods, so operating them at 250C which is twice the maximum rating will definitely destroy it. Use an actual temperature sensor or thermocouple for your application that is within the temperature range you want to measure if you can, you can probably find temperature ICs that are more accurate and are actually cheaper than the NTC thermistor. Depending on your application and circuitry, they might also be easier to use than the NTC thermistor.

>>2578886
> cat 5
Cat 6 is very common now, it has thicker wires so less voltage drop. Practice good shielding techniques. 3.3v doesn’t seem too bad for 10 ft, but yeah, buffers wouldn’t hurt. If you can find the noise source (led/fluroescent ballasts, your cheap-ass psu, guy watching tiktok on cellphone right next to the test bench) eliminate those. Sometimes is you look at the power spectrum you can see a line of some shit that shouldn’t be there.

I'm pretty decent at DIY in general, and while electronics is not my strongest skill, I've never met a challenge I wasn't up to.
However now I'm trying to plan a project for which the knowledge of what products are out there is essential, and that I don't have.
I want to set up four moisture sensors in planters, these would be connected to some sort of microcontroller powered by one of those small solar panels (don't need measurements at night anyway). The microcontroller would then transmit the data regarding to the moisture readings wirelessly to another microcontroller inside my house (ideally some sort of p2p thing, not WiFi). To this indoors microcontroller I'd hook up a small display to get the readings.
I know how I'd tackle the rest of the hardware (I'd 3D print a housing for the outdoors microcontroller, etc) but in regards to the electronics hardware, I don't even know where to start looking, there's a billion things out there and without the knowledge of what's available I'm struggling to start this project.

Suggestions? (Is my idea flawed btw?)

just to clarify, the planters are right next to each other, so I was planning to have a single microcontroller for all four sensors
also, if the sort of microcontroller that could do this is too powerhungry for a small solar panel, I could improvise a way to get power to it via a barreljack or something

I have done things with arduinos before, in fact I have an arduino uno sitting around catching dust right now, but other than that my experience with microcontrollers is limited, I'm more used to working with SBCs but that would probably be overkill here

What tool do you use to draw a layout of panel connectors, buttons, switches, terminals, etc. and how they connect to the main board? I guess I could just use any tool like KiCad and draw them schematically. But I'd like to also draw the actual physical panel with the proper holes for various connectors etc. What's even the proper terminology for that ?

>>2579034
>ideally some sort of p2p thing, not WiFi
I played with transcervers before. Those are cheap and easy to program. But that was years ago and probably there are better chips. They had a pretty decent range.
SI4432 (470Mhz to 900Mhz) NRF24L01+ (2.4 Ghz). There are easy to use libraries for them. So you can either design your own handshake / protocol on top of that or just send / receive raw bytes.

>>2578965
I need the diode for levelshifting because the reset input isn't 5v tolerant. But your solution will probably work with a diode if i use a schottky. Thanks

>>2579016
Uhh. I meant that lead-free should be only used for plumbing lol.
Still. I could solder 3/4 copper pipe with small butane torch if solder was 50/50 leaded, but with 95/5 lead-free it was taking too much time and I bought a mapp gas torch.
Same is true for electronics solder. I got Sn99Ag0.3Cu0.7, I had to crank up to like 440C. Then I added shim between heating element and tip and it started behaving much better. Still not leaded solder. >>2578891

>>2579034
WiFi would simplify a lot of things though, because you can just offload data collection to server with something like InfluxDB. Then you just run a grafana instance and you get custom dashboard in minutes which also allows you to see the data in a way you would never be able to do with some tiny screen attached to arduino. I did this for my central heating wood fired furnace to see if I need to add more logs to the fire and to potentially prevent it from getting too hot because air regulator gets stuck sometimes. You can even setup triggers to sound alarms if you want. I built it using arduino, a couple of thermistors and esp8266 in 2 days and it still works flawlessly and now I have months worth of temperature data.

I had originally planned to do it as custom hardware with LCD display, but it's just 10 times more work for an inferior solution that is also less reliable because debugging embedded hardware just isn't fun when intermittent faults happen once every few weeks. Embrace the IoT bloat and just use other people's code, because 95% of your problem is already solved, you just need to connect few things together.

>>2579062
I'm doing fine with 400°C.

>>2579065
Some of my tips are pure copper so it is not that great as they would just disappear at 400C.
With lead-free you kinda want T12-alike irons i think

>>2578958
Thank you anon, you helped a lot. I started the scheme from scratch in KiCAD and it's much better than EasyEDA. I also took photos of the board from both sides, it's also easier than spining heavy and fiddly pcb in hands.
The diode marking is like 1R5 ZY 9.1 but it is very hard to see, maybe some letters are wrong. But it should be zener.

>>2579051
no diode is needed as no current flows through the transistor from base to collector or gate to drain
simulate the N-channel MOSFET or NPN BJT circuit and see for yourself

>>2579072
The ZY9.1 is a 2W 9.1V zener diode, which makes things easy. No clue what the 1R5 means, probably just a manufacturer specific marking.

>>2579064
>because 95% of your problem is already solved, you just need to connect few things together.
Not him but that sounds incredibly depressing. That is true though. If you ever think of building literally anything just look around, someone has already built it and put it in production and you can buy it really cheap. Which is why this hobby is more about learning things out of curiosity. But you can always say fuck it and take the instant gratification route and connect a few things together and pretend that you've "built" it.

>>2579072
I'm looking at this project you're doing and it looks interesting, QRD? You're reverse engineering some kind of board?

I want to build a shitty proof-of-concept oscilloscope. This means I need a front-end. Originally (a while back), I was going to use op-amps for their ease of gain setting.
However, now I know much more about their non-optimal behavior.

If you guys were to build a basic front-end for a shitty proof-of-concept digital sillyscope, would you use an op-amp based one, or use transistor amplifiers?

>>2579081
I do try to reverse a board but im a total noob. This is a tube preamp for guitar.

>>2579076
>instant gratification route and connect a few things together and pretend that you've "built" it.
What difference does it make? You're already using an IC that is basically alien technology which you will never be able to make yourself. Or take a C compiler for example. Slapping a library on top of tens of millions of lines of code and complex algorithms that were developed by multiple people over 70+ years which together took more time to develop than several hundred average lifespans of a person. Can you really say you built anything at this point? Not to mention all the mining, chemistry, logistics and other things that happen in the background so you can get your IC. We're all just connecting things together and sometimes we like to pretend that connecting things together in a roundabout way is somehow better, because reinventing a wheel for a hundredth time is a good way to spend your evenings.

>>2579086
Ah looks like a cool project, but every time I see the word guitar, I lose interest because I can't play the guitar lol.

Is it possible that manufacturer of a voltage regulator flipped pins at some points and now the datasheet shows Vin but on a PCB its Vout?

>>2579098
Not if they are the same part from the same manufacturer, although most manufacturers of the same part usually share the same pin out configuration for a specific package. Either a) the board has been reworked and someone fucked up or installed a different part, or b) the silkscreen is lying or you didn't read it properly. My bet is on b), maybe you made some translation error and inverted the 3 pins.

>>2579098
>>2579100
Nevermind lol im retarded, its even written BOTTOM VIEW so it's naturally flipped looking at a board.

>>2579101
there you have it haha

>>2579094
You are not wrong. But what's the conclusion? At the end of the day we just need a dopamine dose so it doesn't matter what we do.

Last question for tonight i promise. What is this component? I cant find anything like this, it's almost zener diode but it doesnt have 3 black bands. It's not resistor either.

>>2579075
If i dont have a diode current will push from the 5v pullup to the 3.3v supply. Allthough it will be a small amount i would prefer that it didn't happen

Here is a better quality picture >>2579141

I finished the power supply section i guess. Dont know how those output rails should be called. They go into switches potentiometers etc. Btw these components >>2579141 are signal diodes КД522Б from post-soviet countries lel, a copy of 1N4148.

>>2579143
Don't use a pullup in the first place. See my circuit diagram I wrote? No pullup on the reset pin, works fine. Can do the exact same using an NPN. There's a pullup on the transistor's control line, but that can't send a voltage through the transistor.

>>2579145
those look like 3 band resistors, 0 ohms. In other words, they are jumpers. IT's weird because usually for through hole boards like that they use just straight wires. Might be something like a fused jumper perhaps?

>>2579145
Hmm, on second thought, they could be thermistors.

>>2579145
https://maker.pro/forums/threads/zener-diode-identification-color-bands.271695/

>>2579145
>>2579221
glass gas discharge tube for overvoltage protection.

>>2579175
Wait that R2 and R3 are in series with the 0V, not the +12.4V rail? That implies they're just making a really low-noise ground. The zener there can handle ~0.2A before reaching its power limit, not really sure if it's meant to be a higher-power and/or lower-noise rail than the 15V regulators. Chances are one is for a lower-noise part of the circuit than another, like a preamplifier stage.

Also when you get a voltage with X volts RMS, its peak voltage is X*√2 = X*1.414, so when you rectify and filter it you end up with X*1.414 volts DC, since the filter capacitor fills up to the peak voltage. So you may need to increase the voltage of your rail titles.

KiCAD has names for nodes like AVDD and AGND that you may want to use, it also has a symbol specifically for a 3-pin wall plug.

>>2579231
>KiCAD has names for nodes like AVDD and AGND that you may want to use, it also has a symbol specifically for a 3-pin wall plug.
Not the same guy but was curious about it when looking at his schematic. can you give a bit more information about that?

>>2579221
>>2579226
But later I said I found it, it's a simple diode, use google translate if you really wish to read about it https://shematok.ru/diody/kd522b

>>2579231
>Wait that R2 and R3 are in series with the 0V, not the +12.4V rail?
No, it's my mistake. I had it right, but then moved them and fucked everything up. Thanks anon, the resistors have to be on + rail.

>The zener there can handle ~0.2A before reaching its power limit, not really sure if it's meant to be a higher-power and/or lower-noise rail than the 15V regulators. Chances are one is for a lower-noise part of the circuit than another, like a preamplifier stage.
Im sorry I cant answer this, don't have necessary knowledge. The diode says ZY 9.1 and it's soldered upside down. Maybe 9.1 is not voltage. I'd have to unsolder it and check it's another side for more info.

>Also when you get a voltage with X volts RMS, its peak voltage is X*√2 = X*1.414, so when you rectify and filter it you end up with X*1.414 volts DC, since the filter capacitor fills up to the peak voltage. So you may need to increase the voltage of your rail titles.
Does that mean my 12.4 AC will become 17.5 DC? This is some funny voltage...

>it also has a symbol specifically for a 3-pin wall plug
It's actually a receptacle IEC-320-C14 with a fuse like in the back of your PC, you put a cable inside. I didn't find it, so used general connector.

>>2579143
the fuck are you talking about? that nmos level shifter i suggested will work perfectly fine. the 5V on the gate doesnt "send" voltage anywhere near the 3.3V.
>prefer no loss
hatr to break it to you mate, your mess of resistors and diodes wastes more power than a nmos switching a 3.3V line through a resistor

>>2579250
soviet diodes haha, thanks i'll look at it.

>>2579233
KiCAD has built-in power symbols, going by menus:
>Place
>Add Power
Or just the keyboard shortcut for me "P". I think they're global. There's a variety of numerical or conceptual labels. It's also where the pspice important labels are stored, in case you use KiCAD as a sim. Pretty sure you can make custom ones via the standard symbol browser.

Also "AVDD" and "AGND" are more specific terms for when you have multiple voltage rails. "A" usually stands for "Analogue", so AVDD would usually be a voltage rail with better ripple rejection. In case you were asking about that instead.

>>2579250
>Thanks anon, the resistors have to be on + rail
Then you've got quite the variety of different voltage rails.
>Maybe 9.1 is not voltage
The way you drew the diode in the circuit initially makes it very likely to be a zener, and since the ZY 9.1 is a type of zener I can't imagine it isn't a 9.1V zener diode. Zener diodes are often used in this configuration to produce a regulated voltage rail, though the regulation is less efficient than something like an L78L15. Anyhow it doesn't particularly matter how much power it can provide unless we get stuck reverse engineering.

>Does that mean my 12.4 AC will become 17.5 DC? This is some funny voltage...
Yeah, but it will be lower by a volt or two due to the drop through each diode. Plus your mains voltage will vary by a few percent anyhow. It isn't critical.

>It's actually a receptacle IEC-320-C14
>I didn't find it, so used general connector
A symbol doesn't imply a certain footprint, I'd have just renamed a Conn_WallSocket_Earth to "IEC_C14". But it's hardly important.

So all the power rails are referenced to the same 0V ground point? I'd expect a floating rail for powering the filament, but I'm a tube noob so maybe they don't need that or are getting around it by using a tetrode or whatever.

HAHAHAHA
it's all one path now
AUTOMATICALLY
now time to scale it properly, raster the white bits out of concentric circles, and export a g-code for my laser

>>2579084
Osc mfgs, hp, tek, etc use transistor front ends, you can get schematics for some of them. They use that because, if you need specific characteristics, in theory you could use high frequency/high voltage transistors.

is this just an ordinary DC motor?
how is it being driven?
I would like to make my own adaptive trigger, but i'm not sure how to drive that motor so that i can provide varying amounts of resistence

>>2579364
oops forgot link
https://www.youtube.com/shorts/KPcHJHE5G34

>>2579365
could it work if i used simple pwm to drive the the motor where 0 doody cycle = no resistance and then by raising the doody cycle the motor will resistor more and more? won't that burn the motor?

Umm..what is the resistance of those input pins on the left side?
I assumed it's near infinite like on op amps for example.. is it low enough to slurp up all juice from a 50k pull up resistor? if yes then i'm in some deep shit

>>2579387
fuck fuck FUCK
it outpulls the fucking pull up resistor
i can't believe i overlooked that shit, of course it does it's a fucking tranny not a fet get, it's so obvious now
god damn it i will have to manually jumper wire so many fucking pcbs

>>2579366
>won't that burn the motor?

that looks very much like the 50-cent DC brushed motors they use in toys.
obviously you cant PWM that coz that would cause constant spinning.
almost certainly they have limit switches to stop it when it reaches max/min position, like the switches in a CD drive.
if you wanna emulate that, you'd use a servo, or if you're real fancy, a stepper.

>>2579390
>fuck fuck FUCK

ah, you're the dude who went straight to PCB instead of testing on breadboard first.
so, you got what was coming to you.

>>2579409
>limit switches to stop it when
you don't need to stop it, when the gear moves the trigger all they way it will block the motor from spinning, the motor is only there to provide resistance

why is it that we want BJTs to operate in their linear regions but not their saturated regions, whereas we want MOSFETs to operate in their saturation regions and not in their linear regions

>>2579457
Because region names are swapped for the devices, but actually refer to same region on I(V) curve. Saturation region of FET is equal to linear of BJT.

Is it allowed to rotate transistor symbols on a schematic?

>>2579508
Yes, why wouldn't it be? You can position them in any way you like as long as pins retain their meaning.

>>2578155
bump

Spent hours today on the switching section, still not ready. Its a fucking labyrinth, why did they make it so complicated, it's just 3 switches and 3 LEDs. Holy fuck i bet its possible to do this with 4 wires and AVR8 or something.

>>2575936
Which soldering iron should I get?
Any one have any of these, how bad are they?
I had a look at two[Draper 61478 & Sealey SD008]
that are available in Physical stores &
another two[Yihau 926LED-IV & tilswall station] that I saw online.
I wanted to keep the price around fifty since
I won't use it that often,
just for mouse micro switches & maybe a keyboard.

I made a cmoy headphone amp but the output goes to a 1k:8ohm transformer that drives the headphones. It sounds way better than it has any right to. The +/-9V supply is plenty of voltage and the step down of the transformer allows for more current. Makes a really excellent way to play guitar quietly.

I'm wotking on designing a PCB for a mega drive repro cart (to learn), and the original pcb uses an electolytic 16v 47uF cap going from voltage to ground near the edge connector, and on another spot near the edge connector, on another voltage pin there is a non-polarized 50v 0.1uF capacitor. I've seen variations of these repro pcbs, with different value capacitors, sometimes they have one on each voltage pin like on the original pcb, but then they'll have each be 22uF, and have another 0.1uF right next to the flash chip. How the hell do I figure out what value of capacitors I should be using on my custom pcb? I'm assuming the se capacitors are used as low-pass filters. Please help me this is babby's first kicad project!

>>2579625
VCC is 5V, and to clarify on other's custom PCB's that third capacitor I mention is additional, not present on the original PCB, and is near the Flash Chips.

>>2578663
>will it melt or something?
Yes. At 250C you want a thermocouple

>>2579625
>How the hell do I figure out what value of capacitors I should be using on my custom pcb?
What you need to do here is to learn about PDNs (Power Delivery Network). You need to figure out output impedance of your power supply and impedance of traces and other elements to then keep power network impedance below some acceptable level. It's not a simple problem and adding components randomly could make things worse, especially if you're working with digital logic that has fast rise times. And to make things even more complicated 16v 47uF capacitor is not just a capacitor, it's also a resistor and an inductor, values of which are different for each specific cap from one specific manufacturer. Same for ceramic capacitors which have added benefit that their capacitance varies with applied voltage. You can either learn all about those details, transmission lines, field propagation and other high frequency black magic or simply copy over recommendations from the datasheet and hope that there will be no significant issues or weird glitches. Feranec on youtube has a lot of videos on this so you can start there if you want to learn more.

is case size 3816 the same as 1506? I'm confused.

What happens inside this tiny USB C to A adapter? Is it just a pin-to-pin map, no active logic of any kind, right? The price range is just wild, from $20 apiece at BestBuy to $3 for 2pcs on Ebay. wtf

>>2579652
The bux fiddy ones are going to be chinesium. The 20 bux ones are over priced and branded.

I have one of these tft screens (ST7789V driver ic) but I don't understand the point of MISO pin. Why the screen communicates back to MC? (And touch screen pins are different so it is not that). Other TFT screens I worked had no such pin

I am driving it using TFT_eSPI and it has a define for MISO pin so I used that define. But the screen works even if I disconnect the miso pin. So it is probably useless, or maybe only used in certain commands? I guess i need to read about ST7789V ?

I guess it should be fine to just leave miso unconnected? Or maybe connect to ground with a 100k resistor or something?

If I have three 3 phase cables of 600A 400V. Can I say I have a capacity of 720KW flowing through ?

>>2579652
It depends on what you’re using it for.
If low current charging, usb c/a probably still supports the old 5v, 500 mA original spec with two wires.
I say probably because every USB C vendor supports their own bespoke bits and pieces of the 2300 page spec, and many have their own proprietary uses of USB C (e.g. apple)

>>2579677
>maybe only used in certain commands
I guess this is the answer, I just noticed there are stuff like reading pixels back so miso must be used in such cases

>>2579701
I'd like to hook up my USB-A only laptop to a USB-C docking station. But the more I read about, it is most likely not going to work, particularly HDMI. Apparently that type of adapter is not even defined in the spec. Life is hard.

Finished the part with the switches. Kinda broke my eyes on this, way too hard for a first time. Probs tons of mistakes as well.

>>2579719
Interesting board layout. Looks like it was done on the 70s in the letratape era.

A bit odd how the traces are unnecessarily “square” — even odder that, even today, trace layouts are waaay too square: it’s absolutely terrible for high frequency stuff. With software assist they should look something more like a lot of older hand taped boards. They are also missing out on a lot of optimizations. But nope! Gotta be square like the el cheapo and appropriately named LACK ikea table.

That might be the biggest “elephant in the room” problem with almost all PCB designs today, reminiscent of the Times Roman problem.

>>2579387
>>2579390
Bro, i'm high af, and for some reason this made me laugh crazy. What the fuck dude, you didn't even test your circuit on a breadboard, or build a prototype pcb before going full production?

>>2579790
Are there youtube videos about natural looking optimized tracks?

>>2579409
>>2579792
The last time we had a mistake on the final PCB after it went into production, we just had underpaid chinese fix them.

>>2579364
>>2579365
Assuming they have a seperate reading of the position of the trigger. With that kind of setup they're probably just PWMing the motor in one direction to provide torque counter to the spring (i.e. in the same direction as your finger-press), or to replace the spring itself (i.e. in the opposite direction to your finger-press). The more you PWM it, the more current flows, and so the more torque it presents. The frequency has to be low enough to not feel the ripple with your hand (1kHz is fine) and the PWM duty-cycle probably has to be fairly low to not overheat since the motor is basically always stalled.

It would also be possible to use it as a servo to ensure that the trigger can't be pressed beyond a certain point, if it can provide enough torque without overheating. The gears will help with that.

>>2579387
Read the datasheet next time, or use MOSFETs instead.

>>2579390
Are you using GPT?

>>2579409
bro you know you can stall a brushed motor, right?

>>2579508
Yes. Often a series pass transistor (e.g. an analogue switch FET, or a common-base amplifier) will be left-to-right. Otherwise they're usually arranged such that conventional current moves from top to bottom. If you put your P-channel MOSFETs with their drain facing up I'll eat your dog.

>>2579550
The base being more positive than the collector of those BJTs seems like an error to me. Are those transistors backwards, or possibly are they PNPs? That or the capacitors are backwards.

>>2579585
Consider a variety of T12 station or a Pinecil.

>>2579793
Mitxela did a couple about curving traces for aesthetic reasons. If you're after high-frequency circuit design look elsewhere though.

>>2579859
>The base being more positive than the collector of those BJTs seems like an error to me. Are those transistors backwards, or possibly are they PNPs? That or the capacitors are backwards.
Apparently I mixed up the pins of transistors. Fucking sake I double checked it and I swear the collector was on that side....

>>2579678
>3 phase 600A 400V = 720KW ?

no
you're doing 600x400x3
but consider that current coming in from one phase is exiting through the 2 other phases
since it's the same current, you're double-counting its power contribution
so you cant multiply by 3; you use some lower factor which i have long forgotten.
probably square root of 3.

>>2579289
fuck

>>2579792
>you didn't even test your circuit on a breadboard,
who the fuck does that anymore?
do you have any idea how annoying would it be to breadboard 10 smd components where each has like 20 legs? you would have to make breakouts and shit, so unless it's some very experimental design then it's okay to be lazy and not pre-test
.. not to mention i get paid by the hour anyway

>>2579859
>Are you using GPT?
yeah, i am too lazy to read data sheets, because instead of having one page where they summarize the important parts every datahseet has like fucking 20
you don't need 20 fucking pages for a tranny, so GPT has been a godsend. i can ask it specific questions about exact components and get a quick and short reply with all the info i need. It's like having an experienced engineer on a phone 24/7.
This is the future of EE. Adapt or be left behind.

Fucking hell, I need to buy myself a heat camera, turning a circuit on and waiting for something to start smoking is so stupid. Or touching around with my finger until i burn myself to check if something is overheating is also shitty.
But man, they are so damn expensive, even the chink ones ;_;

>>2579932
I wouldn't trust anything that it spits out, because it's chat GPT not engineering GPT. It can't even do basic math properly like you had in >>2579390
>(5-1.2)/2.7m = 1.407k
It was off by 5% and this is only elementary problem. Now imagine giving it anything slightly more complex. Might as well give a calculator to a retard ask him to play with it for 5 minutes and then read the answer from the screen. I'm not even sure about other numbers, but I don't know what was the input question.

>>2579890
Thanks for taking attention to answer.
There is 3x (3-phase) cables.

Why does a brushless motor called DC if the current going into each phase is sinusoidal and alternating?

>>2580030
dunno. my guess is because usually you spin it so fast that it just ends up being a dc square wave as the input. or perhaps its because it runs off dc power supply. it just gets modulated as 3 phase.

>>2579711
Your USB A laptop will talk USB A protocol to all the devices. USB C devices should talk USB A back. But the USB C level features of the devices won't be available.

>>2579932
>>Are you using GPT?
>yeah, i am too lazy to read data sheets,
Why do people like that exist?

What is the optimum current type (AC/DC) and voltage to transfer electricity from my house down to the workshop 350m (1000ft) away? No industrial converters please.

>>2580062
How much amps do you need? And how much money are you willing to spend on cables. The cheapest option is to just use standard line voltage and size the cables according to your amperage requirement.

>>2580032
>>2580030
it gets modulated as 3-phase after being fed a dc input by a controller

>>2580066
Exactly. The controller is DC, but the motor itself has nothing to do with DC, because it takes and uses AC.

>>2580064
>The cheapest option is to just use standard line voltage and size the cables according to your amperage requirement.
I've checked wire gauge calculators and two 2/0 AWG wires would cost me around $1.5k which I literally will have to bury into ground. Wtf?

>>2580069
the controller is normally built-in to the motor itself, it gets fed pulse and DC

>>2580084
>normally built-in
What?

>>2580072
Yes, that is a chonky cable. But only other option is to mess around with transformers to boost voltage so you can use thinner cable. This is not recommended because 230V is already dangerous enough and boosting it to 5kV/10kV could kill you almost instantly. I'm not even sure if you could buy a proper transformer you would have to DIY it from steel sheets and deal with all sorts of issues.

How do I model a water pump? I would assume it just falls under some category of motor, but I'm not sure and I don't see reference to pumps in the book on machinery I used in undergrad. It will need to pump from a creek in my yard into a barrel and then out to the irrigation lines, so idc if i need 2 or can get by with one. the amount of displacement isnt really an issue as I will only be feeding a few raised beds.

>>2580093
You basically need to find pump head vs. flow rate chart of your pump and then also find your system curve, which is difference in height + some function of pipe resistance.
>https://www.engineeringtoolbox.com/pump-system-curves-d_635.html

>>2580093
Are you working on rice fields.

>>2580097
Thanks
>>2580098
homie it literally says raised beds

>>2579932
But it gives wrong answers. I looked up the difference between two ICs once and it told me that one was USB and the other was serial. But they were both USB. It's just not accurate enough yet.

>>2580030
Because traditionally they were fed a square wave, that's still often the case. But these days there is sinusoidal and even field-oriented control methods that make them much closer to a permanent-magnet synchronous motor.

>>2580072
Do you actually need 16A? If so get a pair of HV transformers and do it that way. Better yet, use gas-power.

What the fuck just happened?

>>2580146
Capacitors retiring, hire new ones.

What's a physical meaning of an inductor. It's easy for resistor, I imagine it as a smaller pipe size. It's easy for capacitor, I imagine it as a storage tank. Easy for transistors or mosfets, which I imagine as switches. But what about inductors? It's kinda cringe to me.

>>2580168
Two buckets connected by a hose at the bottom on a spring-loaded teeter totter.

>>2580172
But why would you want to use this contraption? Everything listed above is being used in real world. So I guess I would need a better analogy even if yours is accurate.

>>2580168
you can think of it as a river with a watermill. As you charge the inductor with current, it slowly starts spinning, then when you cut current, it slowly starts decelerating. How fast it speeds up/slows down depends on the inductance.

I also have another question. How to buy transformers? For example here >>2579719 the transformer has three outputs 230:12.4, 230:16.8 and 230:280. Let's say I want to make the board and buy parts. What would be my transformer part? Or do I need three of them? Can you give one example of a transformer from a Digikey/Mouser that will work for this board?

>>2580200
Thanks, I will use this from now on.

How fast can I drive a NEMA 17 or NEMA 23 stepper motor? I don't require zoooooooom but I can barely get 3.3rpm (not a typo, one revolution every 18 seconds) out of a 28BYJ at 5V. I'm using a RasPi, and the board is capable of running much faster but the motor doesn't even move. If I lower the delay between signals then the motor starts missing steps.

Put another way, what's the minimum stepper motor I can use in conjunction with a RasPi to get 60rpm or one revolution per second? And what driver board would I need for this?

>>2580168
The energy stored by the inductor is the kinetic energy of the water in the pipe. If you have a long pipe with a pressure source atop it, it takes time for water to gain speed down the pipe even if there’s no flow resistance via a valve to ambient pressure. If you suddenly turn the valve off, you get a sudden spike in pressure, which can easily be higher than the source pressure. With a one-way valve added, you can make a hydraulic boost converter, as codyslab did once, and basically perfectly mirrors how an electronic boost converter works. This is also known as the water hammer effect.

>>2580215
Obscure multi-tap transformers are a pain to obtain for sure, especially now that tube circuits are basically a thing of the past. You can try and browse digi-key for them and you might get lucky, but I’m not sure if the parametric search tool is good for that. Might be best off looking at manufacturer websites. An exact match isn’t as important where a voltage regulator is used. Individual transformers may be the only option.

>>2580278
What is the voltage source? And what kind of load is on the motor? Ultimately it’s a matter of torque. Higher speeds and lower voltages reduce the torque output, while mechanical load increases the required torque further.
>inb4 5V

>>2580298
Thanks. Is it a good idea to reel my own transformer on a 3d printed base?

>>2580298
>What is the voltage source?
The RasPi's +5V/GND pins

>And what kind of load is on the motor?
None whatsoever. I'm just at the stage of writing code to figure out how to turn the stepper.

Keeping the load low (and hence the required torque low) was a primary consideration. It won't be much.

>>2580309
>The RasPi's +5V/GND pins
Isn't it the first rule of development board usage? Never power things using power of your microcontroller or something like that.

>>2580312
>Isn't it the first rule of development board usage? Never power things using power of your microcontroller or something like that.
Yeah I'm gonna get a three-pack of 18650s if I can ever find a shop that carries the fucking things. Until then, I'm stuck with the Pi.

>>2579932
If that’s the future of EE then we’re all doomed.
https://youtu.be/xGzJGgQeSDE?t=242

>>2580146
>>2580154
He let the magic smoke out.

>>2580304
> own transformer
Nowadays, you’d probably get a single, high current 12v switching supply, and 3 dc/dc converters.

>>2580342
One of the rails is apparently 280V DC, can I get a converter like that?

>>2580304
Some people do that for sure. I saw a near 3D printed toroid winding jig a while ago. 3D printed plastic itself is pretty shitty for heat and magnetics, but it’s perfectly usable as a mould to slip the completed coil off and onto a split-core of some sort.

>>2580309
Too low a voltage. Assuming your driver can handle it, I’d want 12V if not 24V. Use a boost converter I’d you have to, just put big caps on either side.

>>2580342
Not for audio you don’t, old iron transformers are still used for amplifiers and other hifi gear. With a nice CLC filter and maybe a capacitance multiplier you should get an acceptable noise floor, but it’s still going to be less reliable. Same reason soldering stations still use transformers.

>>2580348
Sure, why not? A lot of switching power supplies immediately convert it to 170vdc before stepping it up or down.

>>2580356
My vox nutube guitar amp uses a switching wall wart. You’re probably thinking of chinese knock off usb switching power supplies that “my first teardown” videos proliferate. We’re not talking about those.
Audio switching power units use switching frequencies way out of the audio spectrum, specifically for that purpose.

Also, class D, exists. The audio *is* the switching frequency.

We’re also not talking about restoring grandpa’s old RCA receiver to as-was condition with cut-out windows to see the tubes and the bigass transformer.

Soldering stations use them because they have to be heavy anyway to use as a base when you put your soldering devices. I’m sure audiophiles use a soldering station with a -120db noise floor though.

>>2580401
>Audio switching power units use switching frequencies way out of the audio spectrum
So do basically all SMPSs. At least half the shitty switchers I have are over 200kHz. But variations in the amplitude of that ripple can easily get detected by nonlinear elements in the circuit. Unless the duty-cycle remains really damn constant, high-frequency power supply ripple can make it down to the audio range. If your op-amp can detect AM radio broadcasts, then it can surely demodulate AM from your PSU. Of course you could use a well-designed filter.

Personally I've been experimenting with using common household SMPSs for audio and instrumentation purposes and it's definitely possible with the right circuit. CLC pi filter + a pass transistor capacitor circuit of some sort should get you at least like -70dB, after which relying on both amplifier PSRR, and the low amplitude of the noise in the first place, should get you the rest of the way past 16-bit resolution. A capacitance multiplier isn't as good as a zener pass regulator, but I think a TL431 pass regulator is even better. Think it's possible to use a sziklai pair with that setup.
I would use a grounded SMPS though, since common-mode noise is a big issue with those shitty 2-pin wall-warts. Avoiding common-mode noise by using opposite sides of a toroid and some inter-core shielding is a pretty cool thing to do also, and may be necessary for instrumentation purposes. Honestly the most annoying thing is only having one rail, but it's not like you can't have DC-DC converters, or use differential output stages like the cool guys.

>class-D
Not like class-D doesn't suffer from power supply ripple, as that's going into all the analogue input circuitry.
>inb4 you meant digital class-D
Either that's open-loop, or it's using an ADC for feedback, in which case there's your vector of power supply noise.

Reliability is a real factor when it comes to soldering stations, though so is cost and simplicity.

>>2580434

We’re talking about some random 12v supply and dc/dc converting it. So you’d use something like a LM53635 specifically designed to turn absolute dogshit into gold and not interfere with audiophile’s cruisin’ tunes.

Note that this guy’s current amp has the goddamn transformer right next to the preamp, so we’re not talking about getting JWST noise/ripple/hum levels here. Make it, if there is a real discernible problem, add a cap or two (most likely)

Even back in the transformer era we learned from the legendary stan curtis to put your ps in a separate case, away from your amp circuitry. And use a ferromagnetic case, when you do.

Is this circuit good for a monostable switch? I tested it with a circuit simulator with somewhat good results.
The first MOSFET is a 2N7000 and the other is a IRF5305.
I need the load to be tied to ground.

>>2580738
Use toroidal transformers and some shielding and I don’t think you’ll get significant leakage inside the same case. Though using an external enclosure with a coax cable for each rail is the kind of audiofool retardation I’m fond of.

>>2580757
The threshold set by a MOSFET isn’t that accurate, I’d want to use a Schmitt buffer/inverter, like a CD40106, if not a dedicated comparator. But if you’re fine with +/- 50% then the FET method is fine, probably better for quiescent current too.

If you use an N-channel FET and pull-up then the main switching FET is on by default, and there is no quiescent current while on. If you use a P-channel FET and pull-down resistor then the main FET is off by default and there is no quiescent current while this is the case. This latter situation may make a bit more sense if your aim is to save power.

>>2580052
>Why do people like that exist?
Cargo culting shitters

>>2580146
The motherboard succumbed to the capacitor plague.

>>2580146
Someone who saved 10 cent per product and got a $1000000 bonus for it just made his magic work.

>>2580845
Thank you.
A shame I never cared about having a rail-to-rail 12V comparator in my inventory, but I think I should as this isn't the first time I do this.
I'm not that experienced with MOSFETs so I didn't know Vgs(th) aren't that imprecise.

Why do you need MOSFET if a transistor is also available?

>>2580910
It doesn’t need to be rail-to-rail, if your voltage threshold is Vcc/2 (plus a volt of hysteresis) I don’t think you’ll run into problems even when the RC circuit is at the rails. Probably. They do go strange if your threshold voltage is close to the rails though.

>>2580915
To get a voltage threshold instead of current amplification.

Connected the tubes. Need to organize everything nicely...

>>2580961
Looks good. Usually we try and put the ground at the bottom, and the input at the far left. Also, pow3_1 (that’s the 260v right?) would be labelled labelled B+ If i recall correctly. Do no touch B+ :-)

>>2580961
Neat. Looks like you can rename POW1_3 "V_{filament}", that gets you a nice subscript. Is that the 9.1V zener supply by chance? It would make some amount of sense. I'm not familiar with tube circuits, but I guess the filament heats the grid, which itself emits the electrons? That way you don't need to isolate the grid supply, unlike with a vacuum fluorescent display where the filament itself emits the electrons.

As the other guy says, rearranging it such that the most positive rail is at the top and the most negative at the bottom, and with the signal flowing left to right, is standard convention that makes for heightened readability. But don't feel pressured to do that initially, just wiring things out as you reverse engineer them is quick and easy, then you can screenshot that and redo it with better conventions afterwards. Sometimes I do this 2 or 3 times as I gradually understand what parts are feedback and what is the main signal path.

Can someone please point me where do I start in making a design for a 5w 8 ohm audio amplifier? Or a schematic I can follow?

>>2580961
>tubes
https://youtu.be/d8DqWvMYyWg?t=372

>>2581052
>where do I start in making a design for a 5w 8 ohm audio amplifier?

you start by finding $4 CND or $3 US in your seat-cushions.
zero work needed, lower cost than buying individual parts.

>>2581052
>where do I start in making a design
>a schematic I can follow
Those are two pretty opposite approaches. One requires the knowledge of how to design one, the other doesn't. Either way you'll be looking through existing amplifier circuits to understand the pros and cons. See:
>https://www.sound-au.com
Especially 76, 169, and 217. Also monolithic circuits like the TDA1905 or even LM1875.
Once you have a good idea of the landscape around the 5W mark (lots of integrated class-AB chips and some single output stage discrete A/B/ABs I'd guess) you can either choose to look in-depth about how to design one or just copy one. Class-D is also something to consider, especially if you want to maximise battery life.

Hey frens, can you help me with a circuit?
I have 6V 3A solenoid like this
And i need to make it slam open as hard as possible, as in i want it to generate as much recoil as possible.
Normal operation is easy just supply 6V 3A and it opens but i need some way to overdrive it as hard as i can for as short as it can so it doesn't burn, to generate as much force as i can from it
How would such circuit look like in it's simplest form?

how do i learn more about car ECUs, BCMs and other control modules? how they work, how they are programmed, what codes they run, what cryptographies are used etc. recommendations on books and other resources pls?

>>2581081
You have a few options. Easiest is to just use a significantly higher voltage rail, maybe 20V. Then you'd just have to limit the duty-cycle of the solenoid in the steady-state. Second easiest is to use something like a boost inductor (e.g. an ignition coil without the step-up ratio) to store energy and provide a sudden pulse, though you'll have to tune the parameters such that the length of the pulse will be enough to actuate the solenoid properly. The only issue being the slight delay between starting the current through the inductor and releasing it through the solenoid. Third option is to use a boost converter to store energy at a higher voltage in a capacitor and discharge the cap into the solenoid. If your input voltage is 3-6V the solenoid should stay actuated even after the capacitor is empty, until you turn its transistor off again. It's a more complicated circuit, but honestly considering all the existing boost converter modules you can buy online it's an easy thing to hack together.

>>2581242
>How do I learn about proprietary secret sauce solutions that were developed specifically by the manufacturer to do specific things that only they know about?
Just get a job at Toyota as embedded engineer.

>>2581279
> probable “gun” project
they use capacitor storage to crush pennies with their own eddy currents in a coil.
Only problem is switching in a lot of current instantly, it could be a destructive process if you want to do it more than once.

https://www.youtube.com/watch?v=7phIBd4L0xw

>>2580845
> external psu
Remember in the olden days when different components were actually separate metal cases with their own power supplies? Then they started making units with the cassette deck, phono, tuner, equalizer, cd/dvd player and amp all in one unit with a cheap power supply; then you throw out the whole unit when a tiny plastic piece breaks off one of the cassette door hinges.

Modularity. It makes sense to factor out the psu. In telecom, you can have one bigass rack psu that serves lots of equipment in one rack. A so-called “telecom grade” reliable one. They use a 48v standard (which would have worked for audio, too).
Well, That, and ±15v would be nice.

Yes, i realize that some HP/dell/etc systems have removable, dual power supplies, i have a stack of broken psu bricks at work. That’s why they need two… junk. We always loose a few with every power outage. Very hard to fix because everything is so crammed in there, but we give it a shot.