/diy/ - Do It Yourself

Hey frens i am trying to use thermistor for the first time but the problem is i cannot find out any look up tables for the temperatures i need which are up to for 280C

i found this bugman pdf about the thermistor but how do i turn resistance into temperature with this?

>>2588661
shit wait, this one is correct

>>2588661
yeah it's a bitch lol and I completely forgot how
there's some exponential you have to solve and every major company uses different units and shit
I think it's that B25/50, measured between R_25C and R_50C
R_25C is given, B is given
good luck lmao

What do anons ITT thread do for work? I hate my job, like this kind of stuff, but dont have an EE/SWE degree.

>>2588696
I may be wrong but most of us are hobbyists as well.
It doesn't seem like too many professional EEs are into EE related things as a hobby

i stealth mounted some lasers to the front of my car and this is my switch for it... based or cringe?

>>2588753
Why do you have lasers on your car, Anon? I think you should use a giant knife switch for extra stealth.

>>2588753
>using #1 ECX screws to hold the cover plate
1000% cringe.

>>2588753
Poor people in my third world country have started illegally modifying their motorcycles to attach extremely bright headlights so that car and truck drivers get annoyed from the reflected light from the rear view mirror and let them pass.
My father was very annoyed by this and contemplated buying a high power laser torch to blind these cunts.

>>2588696
i graduated 2 years ago with a dual ee/ce degree. i work in the same field as my degree. mostly i do full rnd. idea, schematics, pcb design, and assembly (solder monkeying) for embedded systems. i then program those chips for whatever ive been asked to do. recently ive had to put on my image processing/dsp hat. because i work mostly in the digital realm, i like trying to design analog versions of digital systems to increase my skills that i dont use everyday - smps, motor drivers, amplifiers, analog filters etc

What's the deal with this startup circuit?
Once the regulator starts the output feeds back to the on / off pin via D26 but before that it has to get started up from the 15V rail.
C81 is a tantalum capacitor.
How does voltage get to the negative side of the capacitor to startup the regulator, is it leakage current?
If I remove the capacitor, no voltage can be measured on D25 so the voltage is definitely coming through the cap

>>2588779
Taking a quick look at that shoddy schematic, looks like the capacitor will charge when the power is applied (one cycle of AC) is this a slow-start circuit? Not leakage.

>>2588819
No, it starts pretty much instantly and it's powered from a dc supply

>>2588819
Wait, am I just being retarded and it's just the nature of a capacitor?
When the 15V rail switches on, it's like a pulse and so goes through the capacitor?

>>2588863
Caps block DC and pass AC.

>>2588866
But in the short space of time that the rail powers up it's not really DC as it's changing rapidly

>>2588779
Looks like the input voltage (VIN on IC27) ramps up too slowly for correct power cycle order to happen naturally. D22 is a 10V zener diode, so only when the input voltage is at 10.6V or so will TR8 suddenly turn on, sending a capacitive spike into the enable pin of IC27. That spike only needs to be long enough to get the output voltage up to 5V, by which time it will be feeding the enable pin through D26 instead.

>>2588757
it's those christmas type lasers. i did it for fun and it's a cool trick to have up my sleeve.

>>2588696
There's plenty of cool tech and electronic jobs you can get without a degree. But, the older you get, the more bitter you will become when people in their early 20s are essentially in authoritative positions over you simple because they have a degree. It's especially frustrating when they're stupid as shit, and you actually know more than they do about their own job, but just because they have a degree and you don't, they are there above you and get the cooler job.

I have been a tech for 20 years and it's been pretty much the same story at all of them. You are basically the engineers bitch. You can have literally 10x the experience, and you're their bitch.

Anyway all sorts of manufacturing jobs do all kinds of cool stuff, especially aerospace. There's also various electronics repair jobs out there

>>2588757
Not him but I have autism and I really hate bright headlights. I want to have lasers in the front of my car that aim at the bright LED bullshit headlights and burn them out.

>>2588770
>>2588995
Anyway to break into aerospace or similar without a degree/low cost degree? I’ve got a plc controls job offer on the table for 5/1 but I’m not sure it’ll scratch the itch.

>>2588868
Yes.

>>2588999
>Anyway to break into aerospace or similar
Hiding a ceramic knife and a bomb in your carry-on usually does the trick.

>>2588633
is a 3V low voltage cutoff appropriate for a single cell 18650 being used at low current (10-100 milliamps)? i know that under heavy load (several amps) a 3V cutoff will rebound to 3.2V, but i plan on using my 18650 at a much lower current draw.

Halp plz.

Does case size 3816 relate to 1506? Like are they identical and just a different metric for measurement?

The part is some specific resistor array that I'm sure is sold on digikey but I've never searched anything like this before. It's 47x8 which I assumes it's a network of 8 47Ohm resistors, but now I just need to make sure the size is right.

>>2589100
Why are there multiple people asking about resistor networks all the sudden? What jewtube video did you watch?

>>2589103
how many people? Maybe it was me but I've only asked one other time, so I'm following up with thise question about case size

I want to recreate Bertie the Brain but have zero knowledge on how to do it. Is this schematic enough to do it? I have no knowledge electronics so I will have to learn absolutely everything first.
https://en.wikipedia.org/wiki/Bertie_the_Brain

>>2589055
It's a bit shit, but not terrible. Some people do run lithium ions that low. But your cycle lifespan will be worse.

>>2589117
>Is this schematic enough
Not even remotely close to enough. That's a single tube.

>>2588999
get a low stress clerical job adjacent to it and reverse engineer everything in your spare time

Electronics is cringe as fuck. Nobody understands how it work, maybe 2% know about maxwell eqs, basic questions require a brainstorm from several specialist and everyone says different thing. You sound almost like biologists, those don't understand how things really work either.

>>2589135
>Nobody understands how it work
That you don't doesn't mean we don't.

>>2589144
> doesn't mean we don't
Sure bruh, that's why nobody on youtube could answer for sure how fast the bulb would light up in Veritasium's example including all those "electricians and electronics experts".

>>2589148
>how fast the bulb would light up in Veritasium's example

that's a how-many-angels-can-dance-on-the-head-of-a-pin type problem.
real solutions to real problems like, ''invent a magic wand that can turn the TV on from the sofa'' are what people want, and what people can provide.

>>2589148
Dude, I can understand why you didn't understand that video. Firstly, you are slow of mind. Secondly Veritasium didn't explain the situation properly. But more importantly, I can easily find 3 YT videos explaining what's going on, including one with experimental results.

Again, that you don't understand something doesn't mean no one else does.

>>2589153
>pretend the question is way to theoretical so we don't have to answer while truthfully nobody understands how things really work
Yeah cringe as fuck.

>>2589161
You don't need to explain, you just need to give the time in seconds. Never happens but it's fine my friend.

>>2589148
The question is fundamentally flawed. It completely ignores the fact that a pulse will appear as a result of capacitive coupling between the two sides, and the inductive coupling as current flows to those capacitances. It's a resonant circuit, but because of the light bulb it has really low Q. The light bulb means it's no longer just a question about voltage or current, but about power transfer, and the impedance isn't matched. Ask anyone who understands transmission lines (especially microwave electronics) and it's obvious what happens.

TL;DR the main pulse of current that actually turns on the bulb (assuming the wire is not significantly resisting compared to the bulb) takes the full speed of light (actually I think it's a bit slower) to turn the bulb on. A small amount of voltage does appear near-instantly due to the aforementioned capacitive coupling, but it doesn't turn the bulb on.

You see? Here's this strange combination of reality (resistance of wires, impedance matching, current required to turn on a light bulb) and fantasy (extremely long wire, rearranging the situation so the switch is in a different place as if it doesn't make a difference, and actually using an incandescent light bulb).

>>2589165
>takes the full speed of light
*the full speed of light delay*

>>2589165
I appreciate your answer, it gives more information for me about the problem. But what is the answer then?

>>2589165
Here is the problem, so you don't have to look for it.

>>2589175
The answer is that you get a little current after (distance from battery to bulb)*(speed of light) and all your current after (length of wire from battery to bulb)*(speed of light).

In the real world, the little current isn't enough to light the bulb in a meaningful way. In Verasitum's thought experiment, any current will light his magical bulb, so it lights up with only the little current transmitted by the electromagnetic field.

I added this xt60 connector to an ebike and extended the wires, but now I have doubts that they suffice.
They are 18AWG, around 2*30cm long and the bike is drawing around 10A max.

>>2589210

>>2589210
18 AWG can handle 2.3*120 = 276 watts. If your battery is 28 volt you're fucked.

>>2589135
>Nobody understands how it work
That's why it's called engineering and not physics. Real world is too messy to dick around with same theoretical rigor as presented in textbooks. We use approximations and rules of thumb, exact answers don't have any value here.

>have 100MHz MCU
>50% duty cycle differential PWM at a few MHz out of two pins
>an filter to make it into a nice sine wave and filter noise
>impedance matched to an appropriate antenna
Could this work? I don't see why not. Transmitting a bare carrier at 5mW fuck yeah

>>2589220
Forgot to mention the voltage. It's 37v
though I don't know how that has any significance. The current is all that counts, isn't it?

>>2589220
>2.3*120 = 276 watts
huh?

>>2589252
Yeah I guess? Your available frequencies are going to be a bit staggered as they'll all be integer divisions of 50MHz though, unless there's more advanced PLL registers for multiplication and division. Which there might be. Amplifiers aren't that expensive, and they protect your i/o pin in case anything strange with signal reflections hits you.

>>2589252
absolutely, any sine source through an impedance matched antenna will work.
question is, how do you plan on modulating it?

>father is EE
>always warned me the world was a bad place and i could do everything right and still fail
>told me coworkers will try to undermine me at every turn and wish i fail
>coworkers will try to steal credit and never help you out
>told me i need to be ready to work at least 12 hours everyday if i want to buy two meals a day
>told me EE is an especially difficult trade and everything will always go wrong and i would be blamed
>still wanted me to become an EE

>finally become EE and join a small company
>coworkers are friendly and always ready to help me out
>boss is a great guy, jokingly tells employees to take the day off, doesn't mind if they do
>work hard but nobody works after hours
>launched a couple of products, didn't really face any major problems because we overengineered the fuck out of them
>problems were always solved and nobody cared to pin them to any particular person
>pay is decent
Hmmm surely i must be doing something wrong

>>2589342
Is your dad a boomer or gen-x?

>>2589346
Very late Boomer, just hit his 60s

>>2589353
Things were different back then. He was telling you the truth (except the 12 hours a day for 2 meals exaggeration) so you didn't jump in bright-eyed and bushy-tailed just to get your expectations crushed. Lucky for you the times changed and worked in your favor. Consider yourself lucky and thank your dad for the warnings.

>>2589252
>Transmitting a bare carrier at 5mW fuck yeah

great idea.
we know BJTs are impossible to find, so replacing one with a computer makes a lot of sense.

>>2589360
>Consider yourself lucky and thank your dad for the warnings.

right.
low expectations is the key to happiness.
and it must be true, coz there's even a sign that says so.

>>2589458
That's the blunt way to put it, but I think young people tend to be unrealistic in their expectations from the real world, and when their long-term goals fade away they turn bitter.

>>2589445
Yeah sorry I'm not buying a crystal and dealing with the nightmare that is BJT at RF

>>2589489
>just fix it in software
That's not how this works.

>>2589342
>i must be doing something wrong
Yes : Believing a boomer about anything

>>2588633
what tools do I need to measure a pcb to have it's outline? Any tips?

>>2589546
Did your single mom repeatedly say that you could be anything you want to be when you grow up?

>>2589574
Can you not shit up the thread?

>>2589342
Sure, initially, everything is fine… and there are some companies that can avoid those negative situations, but he forgot one rule: generally, things always get worse. When I was an intern in the 80s, yeah my experience was as you describe. Over time, however:

• Companies invaded with know-nothing zoomer MBAs
• Owners get rich and turn crazy (it’s inevitable)
• Co-workers appear that are more involved with “being an EE” as a cult; rather than getting any actual work done
• Someone quits, you take over those jobs, someone else quits, you take over… repeat. Pretty soon you’re on front-line 24-hour support while you’re emptying the waste bins.

I could go on for a long while.

All these things will happen, just give it time. To be forewarned is to be forearmed. Enjoy seeing the good in people while it lasts.

>>2589578
Back at ya, faggot.

>>2589489
> software dude
You should use software based 32768 quadrature amplitude modulation and inverse FFT transforms to your single GPIO output pin. That way, you can use 100s of billions of transistors instead of 8. Also, don’t forget to use UTF-64, encoded in XML documents which you modernized by putting it JSON, and then encapsulate it in YAML for convenience.

>>2589592
>UTF-64
Doesn't exist.

>>2589568
Vernier or digital callipers are probably all you need. Maybe a protractor or some fine graph paper to put it atop.

>>2589592
Uhhh i don't think a 100MHz micro would be fast enough for that.
But bold of you to assume i need to modulated the carrier at all. I just need a carrier and the absence of it, I'll handle it at the receiver end! Besides I'll be sending digital data anyway so using a microcontroller is perfectly logical, it can store a lot of data and implement all sorts of bit encoding and packets with error detection and correction.

can I splice a light/led bar onto the cord for something else? what considerations do I need to make so it doesnt just burn out or anything?

>>2588999
>Anyway to break into aerospace or similar
it really doesnt take much. i dont have any degree. i had 5 years of electronics repair experience, and was hired into aerospace after that. but I think even less than that you'd get in. but like other anon said, can be stressful. my 1st 3 months sucked, but I was fortunate enough to be moved somewhere I liked and avoided most of the stress and did all the stuff I thought was cool and exciting. after a few years, I took another aerospace job making like $70k, and that was stressful as shit, and between that job and my current one, is what led me to write >>2588995 this rant
but, as stressful as they were/are at times, its still valuable experience and i do a lot of cool shit.

my 1st 4 tech jobs i stayed at them about 3 years each. i think you definitely want to stay at most jobs at least 2 years. basically my resume looks good because of the combination of good jobs along with the fact that i stay at them all for 3 years.

sooo my advice is really, take any tech job you can get, if you are learning and you like it, stay 2-3 years, and move onto a better tech job. repeat that cycle for over a decade and then after gaining almost 20 years experience, being 40, and having 25 year olds act like your boss, realize youd be better off with an associates.

Actually my biggest regret is not joining the military, military experience is a huge plus, its practically equivalent to a degree

>>2589761
>the cord
Which cord?

>>2589768
>Which cord?
The cord that's right there. Are you fucking blind, or what?

>>2589768
It'll be plugging into a US 120v wall outlet. The fan will be around 115V, 3.30/2.20 Amp based on speed. I don't know very much about electricity. I think the core of what I'd want to know is how can I calculate how much "stuff" I can throw onto a circuit that goes into a wall outlet, since I know its volts and amps? Is it just like straight substraction? Like I say 15a - 3.30a and the result is how many more amps I can throw on it? Or I guess I'd do something similar but with watts? I vaguely understand that like in a small circuit I'd use a resister to bring the voltage down for a resistor so it doesn't get overloaded, do I just assume the fan and psu for the lights handle this for me and I basically have some amount of watts to pull from the outlet? Do I want these to be in series or parallel, or does it even matter here?

>>2589829
It's a bit more complicated then that. A single NUMA-15 socket is rated for 15 amps. But a single 15 amp breaker is shared by all the fixtures on that circuit. So if you have 10 plugs and 20 lights, you have to add up everything that's connected to those, not just what's connect to one socket.

>>2589836
So I just apply that math across the whole breaker like you're saying? But the basic idea of putting two things on an outlet like that is sound and shouldn't be a problem? Like that would be effectively the same as having a light and a fan on two different outlets? Meaning that if I could run them separately then I should be fine to wire them up like this and run them through the same plug?

>>2590117
>fine to wire them up like this and run them through the same plug?
No. Do not do that. That you have to ask this question means you don't know what you are doing. Get a multi plug extension and stop trying to burn your house down.

>>2590180
Or picrel if you have some awkward need.

>>2589829
>how much "stuff"
you can do it with watts as long as it's all the same voltage. Your 15 Amp, 120v breakers are rated for about 15A*120V=*1800W*. So the total rating of all devices on that breaker's circuit, their wattage ratings added together, shouldn't exceed that value under normal use. BUT the important part is that *the breaker trips before the circuit fails catastrophically.* If the wiring in your walls for that circuit, or the outlets themselves, cannot handle 15 amps without causing a hotspot or short? it needs to be a 10 amp breaker instead, etc. If the installed breaker is tripping under your load, you ABSOLUTELY NEVER want to replace it with a bigger one or wire straight across. This would be an equally dangerous situation if you had a short circuit or malfunctioning appliance.

Only ever use your washing machine or dryer one at a time, or turn your fans to low/medium? You can probably get by going a little over on that one. If the breaker is sized correctly, it will trip and you'll just move one of the appliances because I estimated wrong.

>I basically have some amount of watts to pull from the outlet?
Your devices have a certain amount of impedance built in. So they will each only suck up a certain amount of current when supplied with a certain voltage, which will be generally UNDER what they're rated for on the box/casing.

>>2590180
>>2590183
This actually makes it sound like splitting them off is exactly what I should do. After hearing that it's now less clear to me how multi-prong extension is any different than just splitting the wires off to the two parts directly. But anyways the point is not really to say yes or no to the stuff I'm asking but to point me at the things I need to know to make that decision myself.

>>2590220
The difference is that the manufacturer knows what they are doing and they are allowed to put this logo on their products.

>>2590319
Yeah, the chinese would NEVER be able to illegitimately replicate such an intricate logo.

>>2590335
Don't buy counterfeit products, problem solved.

I’m so noob that the OP doesn’t even make sense, can you guys help me? I really want to build a consumer fish tank that has all the sensors for PH, salinity, alkalinity, hardness, temperature built into it. I really want to do this because I can build an app where you can put your fish and coral into the app and it will monitor the tanks readings for you and alert you to what parameters need changed, making really small starter reef tanks viable for noobs.

Problem is I know fuck all about actually building and programming consumer electronics. I can do the app, have zero idea how to integrate the pumps, heaters, and sensors into one unit and then make it plug in and run.

>>2590360
>alkalinity
You can get electronic continuous meters but they will not measure alkalinity. There's not a practical continuous sensor for it at this time. All the alkalinity monitoring devices use a liquid or strip chemicals and check the colors with an optical sensor, so they need refilling and maintenance, and it's not continuously sampled and recorded.

>>2590360
It's an old joke data sheet. "Write-only memory" implies you can never read from it.

>>2590364
Damn, I did notice they were expensive, interesting to know that’s why. Even if it does need to be chemical that’s ok maybe, I was thinking making little k-cup shaped pods you can add that will automatically adjust water parameters with the correct solutions would even be good.

I’m really bad at taking care of salt water tanks, but want one really bad, and I couldn’t find anything idiot proof already made, so I’m really interested in learning and giving it a shot just building myself an idiot proof smart tank.

>>2590364
Oh lights too, lighting is a big one I think a lot of noobs like me could benefit from a tank that can just auto-set the lighting to your coral and fishes best suited needs from an app

>>2590381
I mean, most people would say just the salt, pH, and chlorine is enough for most species or environments, you only need to measure and deal with pure alkalinity every week or two, tops. Same with hardness, it takes a while to get off, you don't need to check it remotely every day if you're not changing the water or constantly topping it off.

>will automatically adjust water parameters with the correct solutions would even be good.
that's how the chem based ones work, they keep a reservoir of color indicator and another one of whatever's levels need to be changed, and run a closed feedback loop controlling the flow rate or exposed area to keep each at your chosen setpoints.

>>2590386
>changing the water or topping it off
That’s my thinking though, is that most people wouldn’t want a giant 40 gal salt water tank to start even though they’re easier, I literally think if you had a small 5-10 gal tank that was actually idiot proof, telling you when to top up water and adjusting everything, lights temp salt, for you and telling you when cycling is good, maybe even reminding you to feed the fish and what food, I think that would attract a lot more people to salt water honestly.

Plus it could open up more intense salt water pets to noobs, like you could keep jellyfish or squid’s without killing them because the nice app tells you when somethings going wrong in your tank and how to fix it. And in the long run, just make it foolproof, sell little disposable packs with the food and everything the tank needs people can pop in like a K-cup and keep their jellies.

Please note my thinking is entirely based around me being awful at keeping fish but really wanting exotic fish, I would drop $500 on such a tank if it existed.

are there any books or really in depth application notes that detail how one would build a linear lab bench power supply from discrete components? i understand the basics of op amps and bjts and such, but tying everything together to make e.g. a high quality, low ripple 0-30V, 0-5A linear power supply is overwhelming.

>>2590594
AoE has a diagram for one

>>2590335
You can easily avoid this problem if you don't buy from Amazon.

>>2590594
By discrete do you mean discrete op-amps made of transistors too?

There’s just four main parts:
>power stage - output transistors and their drivers
>voltage feedback error amplifier
>current feedback sense and error amplifiers
>adjustment and readout control
Then combine the two feedback loops with diodes. Those amplifiers are simple topologies that should be trivial to look up, but ensuring stability isn’t trivial. I find spice is reasonably good at finding instabilities in my naive linear circuits, but nothing beats a breadboard. If you for some reason don’t want to feed 5A through your breadboard, then making a PCB with a bunch of extra footprints for capacitors and resistors to tame down the high frequency response is definitely recommended. Usually that’s just a capacitor from op-amp inverting input to output.

If you’re fine with analog meters, then fine+coarse pots and a pair of moving coil meters are going to be decent for a readout. Though a digital system has the advantage of being able to see the set current when it’s in CV mode, and vise-versa. You may consider adding a transistor to short out the output so you can check what current it’s set to.

Another thing you might want to add is a fault protection system, mainly just over temperature protection, though you may consider adding a crowbar. Check what features existing circuits use for sure.

>>2591030
>discrete op-amps made of transistors too?
go away, professor

>>2591039
Hey they’re actually half useful, that guy at sound-au.com made a couple and they’re good for high frequency responses where you don’t need a particularly high GBWP.

First time running KiCad 7 on a big screen. Is the new version or is it my screen resolution but why does it look so ugly and low res?

>>2590675
thanks, i should have checked my copy of AoE first.
>>2591030
yes, the four main parts sound simple enough. maybe i need to stop begin a pussy and just start blinding building stuff in ltspice and then breadboard it. i'm not expecting world class performance, just something that works reasonable well and can go down to 0V and 0A, and be series or paralleled for increasing the output.

>>2591068
its probably not designed for 4k, and is being badly upscaled. if by big you mean like 1080p on a 30"+ screen then of course it looks like shit. screen to pixel ratio is too big

>>2591071
Nah I meant to say I ran an older version on my laptop and I don't remember if it looked that ugly or not but this is a 24 inch monitor. 1920 x 1200. Nothing special. But it looks shockingly ugly. I thought there was something wrong with scaling. When I zoom in it gets a little better. But still holy fuck, look at this

>>2591068
Could be an antialiasing thing, or a legacy graphics support setting. I’ve yet to update because my OS is too old for it, but turning off anti-aliasing is my preference for fonts and graphics.

>>2591070
FYI, for 0V and 0A support you need to have the adjustment pots control the reference voltage of the error amplifiers, not the voltage divider/current amplifier. The digital equivalent is having a DAC each as current and voltage references.

By adding capacitors and resistors to your error amplifiers you can get PID-like response for optimised response speed and stability.

Tried EeasyEDA and Altium for comparison.

Altium looks OK too

>>2591074
your graphics mode is probably not set to your gpu and its using shitty integrated graphics drivers. on my 24" 1080p it looks normal not all pixelated like that

>>2591074
looks fine sissy

>>2591127
>looks fine sissy

thx for that injection of testosterone.
thread was sliding quickly into fraggotry.

>>2588999
>Anyway to break into aerospace or similar without a degree/low cost degree?
Get a job in assembly and schmooze your way in. That's what I did. Assembly requires zero degree. If you already have the necessary quals, and you have a job in assembly, then you see the job postings right away and usually get first crack at them. Some companies require all new jobs to be posted internally for X period of time before they post for outside hire.

>>2589236
>We use approximations and rules of thumb
And experience with similar problems.

>>2589258
Not him, but the full scope of Ohm's Law is at play. With the wattage being fixed, varying the voltage will cause an inverse variance in the current. If your voltage is low enough then your current will exceed your limits. Fiddle with Ohm's Law a little and see what happens to the current when you drop the voltage to 10V or raise it to 100V. Search ''ohm's law power circle'' and find the P over IE formula.

>>2591196
The wattage is never fixed. If someone says they have an X watt Y volt power supply or charger or whatever, the Y volts is your independent variable, X is dependant, it’s secondary. Nobody makes a constant power power supply.

>>2591213
>X watt Y volt power supply or charger or whatever, the Y volts is your independent variable, X is dependant, it’s secondary.
No. X is (somewhat below) the point at which the power supply will overheat and destroy itself, that's all. It is not dependent on V, but R/Z.

A 5000W and 1W, 12V supplies? both put out 12V, no more or less, unless they are broken or overloaded.

>>2589258
>The current is all that counts, isn't it?

It is, >>2591196 and >>2589220 are some combination of trolling, on drugs, and retarded. Current is the only thing that affects resistive heating, as far as DC goes, anyway. Voltage is limited by other considerations: Typically, the maximum ratings of the connected devices is the limiting factor. At the extreme, arcing between conductors is.

Even then, how much current you can actually push through a conductor is only limited by how fast you can cool it off. The 12AWG possibly stuffed into 6" of fiberglass insulation in your wall? Yeah, that can't take much before getting dangerously hot. A copper pipe with water running through it (seen in some induction heaters) can handle dozens of times more current per unit copper.

If there's no code or spec to follow, the only good way to know how much current your conductor can actually handle is empirical testing. If nothing gets too hot after it's been at full load for a while, it's fine. Anything other recommendation is just going to be a guideline. Mind, of course, that the heat being generated isn't coming from nowhere, and you could be loosing some efficiency for cheaping out on the wire. Off the top of my head, 10A through 18AWG in free air is fine. Same gauge used in a lot of cheap extension cords/power cables, most which will only get warm at 10A.

>>2591213
>Nobody makes a constant power power supply.

Strictly speaking, there are some lab power supplies that will do constant power, though they aren't nearly as common as the usual CV/CC supplies. I think most of them are just full-on programmable power supplies that just advertise that feature, but constant power is a thing you can do if you want.

>>2591248
>that will do constant power,
so what happens when the terminals aren't connected to each other while it's set to constant power?

>>2591213
>The wattage is never fixed
That is just not true. I was referencing the load, not the supply. Have you never seen a family of devices designed to provide the same performance, regardless of input voltage? Cooling fans come to mind for me. There are families designed to be run off of 12VDC, 24VDC, 120VAC, etc, that all spin the same rotor at the same speed because they all consume different current levels at different voltage levels and they all have the same wattage consumption. Tell me that you can change the voltage without requiring a change to the current to drive the same power. That goes for you, too, wise guy. >>2591239

>>2588696
I worked in it for the past 7 years, saved up all money i could and now i have enough to be a need until 2030 when the money runs out and i will have to find a new job, so right now i'm just enjoying my neetcation

>>2591253
You're not wrong, but the guy was originally just asking if 10A was too much for an 18AWG wire. That got confused by someone spouting some nonsense about 18AWG only being able to handle so many watts. The voltage in this case is irrelevant.

>>2591250
They just try and put out whatever maximum voltage they're set for. Same as a CC supply would when disconnected.

>>2591248
Yeah, things like LED power supplies often present like a constant power (CP for short) load, though since they usually only have a range of a factor of 3 at most (e.g. 10V to 30V) you don't get the same edge-case of extremely high current at low voltage.

>>2591306
oops, meant to respond to >>2591253

And as the other anon says, the post here >>2591196 is either ignoring the context (selecting a wire gauge for a 10A load) or being deliberately disingenuous.

And >>2589220 is flat-out trolling or retarded anyhow. In what universe is 18awg limited to 276W? There isn't a power rating of wire, it could theoretically provide thousands of watts at a high enough voltage. Where does the 2.3 and 120 come from?

I've got a dead monitor power supply. When you plug it in it makes a high pitched squealing noise and doesn't power on at all (buttons don't work, no display, nothing). Before this used to go away but now its totally dead. I suspected a capacitor problem but when I opened her up they all seemed fine. There wasn't any bulging or shit coming out of it, which I guess I expected because it was made post-capacitor plague.

What do? Should I just replace all the caps anyway?

>>2591351
capacitors first, switching converters second
map out that bigass heatsunk ic on the right (Q901) and make sure everything's still working

>>2591351
>Should I just replace all the caps anyway?
buy one of those $15 transistor/inductor/capacitor testers off ebay and check the ESR of the capacitors first. also check the diodes. there's no point in blindly replacing things if they aren't bad in the first place.

better yet, try to reverse engineer the circuit. if it's squealing then there's some sort of switching going on. is there a SMPS IC on this board, maybe on the bottom? it's obviously a regulated feedback (looks like an optocoupler across the isolation barrier, directly below the transformer), so understanding in a broad sense how the output voltage is regulated is a good first step.<div class="xa23b"><span class="xa23t"></span><span class="xa23i"></span></div>

would anyone mind recommending fpga/memristor projects?

Why does a 3-phase AC from an alternator has to be converted into DC first and then converted back into house AC? Why not simply rectify 3-phase into 1-phase? This smells like invertor marketing team bullshit to me.

>>2591293
>>2591308
I was not ignoring context, trolling, or being retarded. Otheranon just distracted me a bit with his half explanation of the concept, so I rounded it out a bit. It is something commonly unknown or neglected. I did not read back up the thread to see the original context. I ran based off of where he had started going. Anyways, I have seen a lot of newfag errors like that. Carry on.

>>2591399
>3-phase AC from an alternator
For automotive use? Because the system relies on a DC storage battery.

>>2591499
No I said for house needs. It's in a video about micro hydro turbine, the host says they use three phase alternator, that is converted into DC and then back to AC. Why?

>>2591507
>Why?

one possibility is that the turbine produces variable voltages or frequencies as water pressure changes.
and house appliances want fixed voltages and frequencies.
which the DC-AC converter provides.

>>2591507
>I said for house needs
No. You said ''house AC'', and people use the term colloquially. I could only speculate but, what otheranon said about fully regulating it with DC as an interim step makes sense to me. There would be some loss, but not as much as if it were being transmitted large distances.

>>2591571
>fully regulating it with DC as an interim step
yeah, that's almost certainly it to me. Not only do you get 120V 60Hz consistently, AC transfers way better. You might also have some DC appliances/lighting away from the home, closer to the genny, but I kind of doubt it.<div class="xa23b"><span class="xa23t"></span><span class="xa23i"></span></div>

>>2591399

Probably because the guy is using an inverter to bump up the generator's output to a steady 120VAC. Even if the thing already put out a usable 3-phase 120V, you can't just immediately turn it into single-phase AC. You can either just use individual phases, which can have load balancing issues, or you can rectify it into DC and convert it into whatever's most most convenient with an inverter.

If you're a power company providing power to hundreds or thousands of customers, just splitting up individual phases makes sense, because there's a lot of averaging over all the consumers that will tend to balance out the load nicely over the phases. For home use, it's very unlikely that you're going to have even power draw at any point at all. In that case, it makes sense to just gang all the phases together via rectification, then convert that to just one phase to power everything. You take a small efficiency hit in the conversion, but having wildly unbalanced output from the dynamo is probably a lot worse.

Which is the best arduino compatibile cheap chinese temperature/humidity sensor? I tried DHT/AHT and they're meh and too bulky for my needs; tried BME280 but the temp sensor is unreliable as shit, bought some SHT30 and Dallas ones but they aren't here yet
I have a home automation project I want to turn into a business so I need a somewhat consistent sensor dammit

>>2591583
>>2591571
>>2591516
Thank you. I guess it makes sense, especially if he had a battery bank and would like to get the betteries between source and house.

>>2591584
>cheap chinese
>temp sensor is unreliable as shit
>a somewhat consistent sensor dammit

anon, I might have some bad news for you.

>>2591586
Well then recommend some not so cheap american™® ones
What kind of sensor do thermostats usually use?

>>2591599
Taiwanese or Japanese usually.

>>2591603
Or South Korean.

>>2591584
Arduino is a home hobby thing. You might want to look into other platforms if you’re going to be manufacturing it.

>>2591585
>especially if he had a battery bank
Well, this gets back to the automotive scenario that was my false presumption at the beginning.
>massively dirty 3P
>convert to DC
>store in batteries
>convert to clean, regulated AC for use as needed
We did not have a lot of info to go on. With a more complete scenario. We could probably figure everything out. There are not a lot of good new ideas. Everyone mostly does everything the same way given the same requirements.

>>2588779
Current through a cap is C * dV/dt. Value of cap * change in voltage divided by the change in time.

>>2591584
DS18S20 is what you want for room temp.

Does a 3w LED COB need a heat sink? A 486 dissipated 5w and we didn't put heat sinks on those.

>>2591653
>A 486 dissipated 5w and we didn't put heat sinks on those
What kind of pulse drive and what duty cycle? I basically sink everything. Maybe I overdo it.

>>2591653
Those case designs are for heatsinking, so yeah.
Hmm… wonder why the didn’t use a pre-existing design, like a TO-3 or TO-220 mount for high power LEDs.

>>2591658
The 486 was a CPU. Back in the day we would turn our computers off, but they'd still be running for hours at a time.

>>2591661
>The 486 was a CPU
That is so apples/oranges that I did not realize that you were talking about CPUs. That CPU had a lot more surface area against which to sink. Plus forced air cooling. OSRAM and Cree should both have recommendations for their LED applications. I just follow the recs and move on.

>>2588696
I do LV design for solar farms. We do layouts and stringing with AutoCAD/PVcase, running production simulation with PVSyst, sizing equipment and performing cost estimation, and creating IFC packages. Sometimes I run electrical studies with ETAP but we usually farm that out to subs.

It's interesting work but not what I wanted to do when I was getting my EE degree. I was more interested in working with embedded systems, but those jobs are very competitive and I was not good at school. Also, the pay for EE is kind of shit, especially compared to what software guys make. On the plus side, my colleagues aren't a bunch of faggot liberals

>>2591662
Miniaturization, and pick-n-place assembly.

>>2591674
>forced air cooling
Barely any air was forced into those old cases. I'll go read Cree docos.

>>2588633
can anyone identify this diode for me from about 1972
it seems to say 2F within the top black band

>>2591351
dead backlight inverter circuit or ccfl tubes

>>2591707
germanium diode

>>2591707
OA90 looks exactly like that, except it says 3C. So you might want to look at this lineup, there's somewhere your diode.

>>2591716
>>2591728
thanks
hm the datasheet for that oa90 doesn't say anything about the number or letter on it
mine is in something from japan tho I know that much

>>2591074
>>2591094
>>2591096
As a software dev, I really hate how the outer pin labels are shifted upwards by half.

>>2591762
>software dev
>>>/g/

>>2591763
>links the consoomer board
Try harder.

>>2591766
computer """scientists""" are indeed consoomers

>>2591762
>the outer pin labels
The pin numbers? They have to be in order to allow for a circuit connection.

>>2591803
Green ones should be offset 1/2 to align there too then, it's ugly that way like stairs.<div class="xa23b"><span class="xa23t"></span><span class="xa23i"></span></div>

>>2591808
>Green ones should be offset 1/2 to align there too then
I don't agree. Typically, when you are troubleshooting, you point at your gate name with a spudger and drag straight out onto the circuit to find where you think there might be a fault that explains your failure. As a system, it makes sense. Just as a visual stimulus, I understand that it might activate someone's OCD.

>>2591814
sounds like you date ugly, but easy, girls

>>2591815
Well, regardless of that, I have traced thousands of circuits. I know from experience that the orthodox schematic format works. I'll leave you to tilt at windmills if you disagree.

>>2591826
>orthodox schematic format works
sounds like you date a body pillow

>>2591828
You win. Have fun being you.

>>2591370
Looking up the part number, Q901 is a SMK0965 switching regulator MOSFET. Dunno how I would test it though.

>>2591372
I checked the capacitors resistance with a multimeter and they seemed fine. The resistance would slowly increase. Then checking the voltage I could see them slowly discharging to zero.

>is there a SMPS IC on this board, maybe on the bottom?
It all seems to be built into the single board. All the ICs are all connected to heatsinks (the big one in the middle, and on the right).

>>2591711
The power button doesn't light up/respond to input when I plug it in, so I'm thinking it's a problem with the power delivery, before any of the screen components. Also its LED screen.

>>2591642
Got some ds18b20 on the way, thanks, I'll also get some s20. Btw I read that the Google Nest thermostats got a SHT20 inside, so the SHT series should be fine for my needs.

>>2591911
>I checked the capacitors resistance with a multimeter
Not a reliable method. If the capacitors had an ESR of 10Ω, would the DMM's value stay low enough for long enough to notice a difference? Might be able to do it fine with the minimum function on the meter, assuming you can get the elcap fully discharged before measuring it since they like to drift up a few hundred mV. Maybe putting a 1k resistor in parallel would work? Won't be accurate for less than 5Ω though unless you have kelvin sensing, while you'd probably want them to be under 1Ω or so to call them good.

Also I can't imagine there isn't an SMPS IC on the board. An SMD IC soldered on the underside of that same board is what I'd expect.

In addition to the troubleshooting tips from the other guy, I'd reflow solder joints on heavy components or components strapped to a heat-sink just out of principle. Same for connectors or wires soldered directly onto the board. They can get cracked pretty easily. Also look for any discoloured components or areas of solder mask, indicating heat.

Then while running, I'd try to measure voltage after the rectifiers D905/906 to start off. If the voltage is not there you'll be looking at the switching circuit or transformer. If the voltage is there, you'll be looking further forward like to the backlight or control voltage rails.

>>2591911
you test the network around it. high pitch whining implies something's wrong with an inductor (or worse, creating sparks). check to make sure none of those thin wires have broken.
If you don't know how switching regulators work, i suggest you shitcan it or order a replacement

>>2591942
you are not getting anywhere near 0.01°F of accuracy, ditch that last decimal place

>>2591930
>would the DMM's value stay low enough for long enough to notice a difference?
Reading directly off the underside, I'm getting readings of around 0.1-0.5 ohms, but as you said they might not be accurate.

Pic is the back of the board. Might test it later with power so I can better isolate it.


>>2591941
I was gonna give it a shot at fixing it so that if I screwed up it wouldn't be a big deal.

>>2591966
What's IC901? It's likely the switching controller IC the other anon was talking about.

Give reverse engineering a shot if you want, you'd just take a nice flat photo of either side, flip the back, and superimpose in GIMP or whatever. Then draw out the traces and components on seperate layers, and once you're mostly done with a section you can transpose that to a properly arranged circuit diagram, be it on paper or in software like KiCAD. Comparing to the datasheet of the switching converter should help a lot, though honestly you can probably just assume the key parts of the example circuit will be the same as your board without having to reverse engineer.

Ideally you'd have an oscilloscope to look at switching waveforms, if not all you can do is measure components and voltages. Key voltages are rectified mains (output of BD901), bootstrapped/zener supply voltage for IC901, and rectified transformer output.

On a side note, anyone know if those SMTs are wave-soldered with the THTs by using something like adhesive? Or maybe the SMTs are paste+oven soldered with a high-melt alloy, before the THTs are populated and then wave-soldered with a low-melt alloy.

Might be a bit of a basic question for this thread, but I'm using an ESC for a motor and I'm currently setting up the potentiometer throttle.

When I short the 3.3V/throttle input pins the ESC reboots, when it should go to zero throttle/full reverse (depending on configuration). This is an issue because the same thing happens when I turn the throttle all the way to zero ohm resistance.
What could cause this? Would putting a small resistor in series with the wiper help with this?

Hope this question is in scope with the thread.

>>2591966
one of those 8 pin ICs is likely the SMPS IC. search for a datasheet. after you check the diodes, a good next step might be checking the VCC to that IC. is it stable and within the recommended voltage per the data sheet?

>>2591978
part number of the esc

anyone know of any cheap chinky NTC thermistors that are integrated into a metal tab like pic related (which are like $6 each)? i want to do temperature monitoring of batteries but there's not a great way to get good heat transfer with the traditional styled NTCs.

>>2592008
Flipsky 75100, works with VESC.

>>2591978
>>2592112
It sounds like you may be conflating your pins, and shorting 3.3v to ground when the accelerator is in reverse position. It should only ever short the ADC pin to either Vcc/Gnd, never each other, so perhaps you have misrun or misconnected what should be the (green) sensor wire.

>>2592117
Shit, that might be the case. I'll rewire and check.

>>2592074
If you are just trying to contain costs, then you could glue your own to a ring terminal with heat conductive epoxy.

>>2592074
>not a great way to get good heat transfer

do what everyone else does.
dump some thermal grease (heat-sink compound) on the battery.
use scotch tape to make the thermistor sleep in the wet spot.

>>2592196
>scotch tape
That's racist.

>>2592074
I’d heat-shrink a thermistor to an eye terminal with thermal compound packed inside the tubing. Thermal adhesives aren’t too hard to come by also.

still very much a noob here... why isn't this creating 2V at the net labeled output?

>>2592363

>>2592363
>why

an op-amp without feedback is a comparator.
so the output is either close to Vcc or close to zero.
when you use proportional feedback, you want it to operate in the linear region.
that is, it should be making very fine adjustments around 3.2V, not jumping from rail to rail.
another thing is you're dividing the output voltage by 10 so a ref of 2V would yield an output of 20.

Why do different 3D models of the same 0805 footprint have different sizes? Are there different types of 0805 capacitors? I thought the package type should match the footprint. Yet one of them seems too small and the other one is too large.

>>2592400
Enjoy your imperial shit system.

>>2592400
Oh looks like there are different footprint sizes, too, N, L and M. Also looks like if I download both the footprint and the 3d model from the same source, they match perfectly.

>>2592366
Its trying to make 20V, but I think the problem is the current gain of your Darlington is too low for the op-amp to feed the required base current. Try it with a lower resistance load.

>>2592397
He does have a negative feedback loop through the transistors, but it’s stability is somewhat dubious, especially for nonlinear loads. He should add a small capacitor from inverting input to output, then it will be fine.

>>2592363
>>2592366
Yeah your reference voltage is 2V, and you have a 1/10 divider on your output, so it's trying to push the output up to 20V, which it can't because the op-amp power rails are only 10V. You'd need to drop the reference voltage to 0.2V, which is a bit shit considering a lot of op-amps won't operate properly with an input so low. Consider using a split-rail power supply for the op-amp, measuring the feedback and setpoint reference voltage relative to some other reference, or ensuring you select ground-sensing or RRIO op-amps.

On the other hand, if you keep the reference at 2V and push your op-amp power rail up to 30V, you have a current gain of ~1300 and a 1kΩ base resistor, so 13A is about the maximum your system can output, while 20V across a 1Ω resistor would draw 20A. Either way, ensure your op-amp of choice can handle the output current, and consider using a lower-power higher-hFE transistor for the lower-side of the darlington.

>>2592119
>>2592117
Got it, it was my own shoddy configuration. The overcurrent protection was kicking in.

>>2592510
fyi if you try to reflash the bootloader on a vesc while it still has a bootloader you brick it
do not do what i did

>>2588633
Wanting to build an LED grow light array for hydroponics and starting seedlings indoors.
I figure this is probably one of the simpler projects that has practical utility, as it's basically a glorified light. I'd like to be able to achieve this for cheaper than available quantum boards (all start at £150 or so).

I understand that COBs such as LM301H/Bs are suitable for this use case, I understand there's a need for heat dissipation via heat sinks, and that a driver will be needed with a dimmer control if I want dimming.

I've never made anything electronic outside of breadboards when I was a kid. Am I missing anything vital here?
Are there any good resources for building this? Most content I can find is from dude weed lmao types.

>>2592458
i swapped out the op amp for an ideal op amp and it does work. i guess i don't understand why such a high voltage on the op amp output is required? aren't BJTs current devices? i was expecting a relatively small amount of current through Q2 (also at a fairly low voltage), which is amplified by Q1, so as to make VREF = VFB.

> hi guys my project is LED strip illumination
> hi guy my why the voltage is X it has to be Y
/ohm thread lately, have not seen interesting stuff in weeks

>>2592540
>i guess i don't understand why such a high voltage on the op amp output is required?
A BJT is a current-controlled current-amplifier, but that doesn't mean it's fully isolated; it only has three terminals. Practically speaking, when operating in the linear region, there's a constant voltage drop of 0.7V between the base and emitter of a BJT since the BE junction is a diode, so in your case the darlington's input voltage needs to be 1.4V above the output voltage. When you take the 1k resistor into account also you get a voltage drop dependant on base current, which could easily be multiple volts. Ditch the resistor and you get a bit of headroom.

If you want to make the output voltage get higher than the op-amp's output range, you can use PNP pass-transistor(s) instead, and use an NPN controlled by the op-amp to pull the pass transistor's base down, but this drastically increases the total effective voltage gain, and makes the system a lot less stable.

>>2592547
thanks, that makes perfect sense. i guess i should look up some linear power supply schematics to see how they do it. my goal is to (one day) make my own cc/cv linear power supply while avoiding "all in one" ICs like LM317 etc.

>>2592562
they're like $0.50 each but okay do whatever

>>2592522
Thanks for the advice. VESC seems pretty retard proof if you just follow the right instructions by the letter thankfully.

What distance measuring sensor would work thr best for me, if I have these requirements:
- cheap af
- fast af
- range 5 m or 15 ft
I know there are sound sensors, laser sensors, different radio sensors.

>>2592537
>Wanting to build an LED grow light ... (all start at £150 or so)

less than 8 bucks at the thrift store.
i also got a 1000W high-pressure sodium light for $3, but then realized i needed a $300 transformer for it.
guess, i'll have to go cut down a street light to pull the transformer.

>>2592562
Really not that hard to make such a PSU once you understand the building blocks of one. See >>2591030.

>>2592632
Speed shouldn’t be an issue for any of those, check eBay to see which ones are cheapest. Do you care about accuracy at all?

What is this yellow band?

>>2592632
>cheap af
>fast af
these two are subjective conditions. define it specifically. fast in particular is highly ambiguous. by fast do you mean a fast measurement time? or a fast sampling time? other things to consider. sound does not work unless the object is large, flat, and almost perpendicular to the sensor, especially at distances >2m. what kind of fov do you need? is your thing going to be outside/in bright ambient light?

anyway based on your range and "fast" requirements, id say something like the tfmini series could do you well, except they are a bit higher cost due to optics inside the sensor case

>>2592855
ching chong went pp in your cap
yerrow rives matter
thin yerrow rine

>>2592880
YOU WANT MIRRION DORRA
TOO BAD
HERE PISS
FUK U

>>2592876
Due to the pandemic, you can now only pick one (1) of: “good” “fast” or “cheap.” We understand that pre-pandemic you were able to pick two, but that option is unavailable at this time. We do not know when a second option will be in stock again.
Sorry for the inconvenience.

I found a Tektronix TDS210 in walking distance from me for $190 CAD.
I personally don't really have a use for it, probably not going to buy it, but I wonder what you guys think.

>>2592910
>Tektronix TDS210 ... $190 CAD.

thumbs down.
look at a few loonies more would get you (if you were actually buying something.)

>>2592910
>Tektronix TDS210 ... $190 CAD.

two thumbs (and one pecker) down!
look at what a few loonies more would get you (if you were actually buying something.)

>>2592910
I wouldn't buy an early digital scope like that, especially not one that looks to be more on the entry-level side. At 60MHz it's ok, but those early scopes can have issues with screen refresh rate, and they often don't have automatic amplitude and RMS and such measurement. Probably has a trigger level display though, hopefully. I'd also tend to wait for a 4 channel scope when going digital, and stick to something cheaper (e.g. analogue) for an entry-level scope. With an analogue scope and a USB logic analyser you can handle 90% of situations thrown at you, unless your need to sample one-off analogue waveforms often. A USB scope can be a decent and sufficiently cheap entry-scope, though they're often pretty low-speed (e.g. 10 or 20MHz) and you'd need to be able to trust the end-to-end isolation to protect your PC. A teardown of a similar unit would tell you what their protection is like.

A cheap DSO138 is not good enough as an entry-tier scope, 2 channels is a requirement.

>>2592936
I wouldn't recommend any brand shittier or chinkier than Rigol.

>>2592936
how hard is it to even make a 100MHz scope these days? these things should be available for like <$100

>>2588633
I'm building a single phase 220-240v / 32a distro to power a set of amp racks. I've got some help from some boomers on a UK electrician forum but looking for some software to draw out the circuit diagram that includes industrial ceeform/mcb/rcbos/terminal blocks and wire diametres.

Whatever solidworks/fusion360 equivalent for electronics is.

>>2588753
heh

>>2592989
>looking for some software to draw

all electrical cad software is equally atrocious.
if you're a noob and havent learned the 1000 or more quirks each piece of software has, it's pure torture to use.
pencil and paper, OTOH, is quite efficient coz you mastered the learning curve before puberty.

>>2592989
I'm pretty sure people use something like AutoCAD for this. For FOSS alternative check out qelectrotech https://qelectrotech.org/

Does it make sense to build a DIY 8.5 DMM?

Is this typical? I need to solder a resistor on pins 1 and 6 on the bottom holes of this board but it looks like they're filled. Is this just resin I can heat and push a through hole through?

>>2593116
>Is this just resin I can heat and push a through hole through?

those holes at the lower left are full of solder. I'd press the tip of a wire against one and heat with my iron until it pokes through, then pull it back out while it's still hot, leaving an empty hole for the resistor.

>>2593133
Ah thanks, looks like I had the right idea. Is it common for PCBs to have holes filled with solder like that? I've done a bit of soldering on gamepads and fightstick boards but this is the first time I've seen that.

>>2592983
Seconded. More than half of it, like 75% is a crappy smart tv, and i already have one of those.

Video converters, HDMI, and DOCSYS modems, USB 3, Ethernet, etc… all deal in frequencies over 1GHz and have (comparatively) cheap chip sets.

The compute power on a typical very low-end GPU absolutely dwarfs what’s in an oscilloscope. Imagine the kind of real time, wide spectrum FFT updates you could get with a modern high-end GPU. You have to spend $1M to get the equivalent functionality in a anritsu.

They make USB scopes, but they’re still waaaay too expensive for what you get.

Plus, those high-end scopes still have carrying handles on the top of them. For what? 100% of my work is done at the bench. I think they are envisioning an era when you has to bring your scope over to the Univac mainframe to diagnose it. Also, explains all the little knobs that old geezers still like using.

Nowadays, the absolute minimum freq you need is going to around 200 Mhz (input clock for a typical PC processor)

>>2593147
Very common. In fact, extra solder is often used to increase the ampacit of the traces, too.

>>2593099
> build an [accurate to 1 PPB] 8.5 digit DMM

In my opinion, no… how are you even going to calibrate it? Personally, I wouldn’t be able to even correctly use one of those.

> I can fabricate my own josephson junction arrays in my garage with a toaster oven
Okay then.

Of course if it only needs ±10% accuracy, no problem!

>>2593177
>Also, explains all the little knobs that old geezers still like using.
menu diving sucks donkey balls

I'm making an unconventional video circuit, where I can only use wire-wrapping or copper-clad perfboards to contain the components. All SMD components will be put into DIP adapters. Would it be better to wire-wrap using RG179 coaxial (I have a lot of it), or to use the perfboard for ease of use? I am mainly converned with video quality at 480i using component.

>>2593099
No. But it can still be a fun learning experience, if you don't mind paying out the ass for a calibration. See Marco Reps for ideas.

>>2593186
> menu diving
Thats not the only option, there is these things called “video games” nowadays that have intuitive user interfaces and a lot of complex functionality.

If you want lighted panels, glue some xbox controls into a panel and plug it in.

The point was to use commodity, pre-existing hardware.

>>2593192
I would think the little 2.54 cm wire wrap pins would act as little antennas. I’ve never heard of wire wrapping coax. Whenever I use coax, I keep the core as short as possible (inside the shielding) and solder it… and/or solder a “can” around it using sheet metal. Even in audio.

Also, sometimes we use similarly dimensioned shielded wire in audio, but it’s copper conductors, not steel, and never wire wrapped.

>>2593177
I was going to ask about using my PS as a 'scope. But it seems there is no good cheap solution.

>>2593236
>PS
I mean PC

>>2593177
Those are only cheap because of mass produced ASICs. Same reason the RTL-SDR sticks are so cheap. 1GHz processing alone is like $20 minimum for a chip, plus a proper analogue front-end and high-speed ADCs is another ~$25 for each channel. Check out 1GS/s ADCs on digi-key and see for yourself, and check out a modern scope tear-down to see the analogue circuitry.

>>2593236
Do you mean using your sound card? People definitely do so, but you definitely also need some sort of protection circuit and buffer. Personally I wouldn’t settle for anything less than magnetic or optical signal isolation, so unless you dive into making your own PCI-E card with optocouplers, you’re talking a USB sound audio ADC of some sort. I’d want to make my own to avoid the usual AC coupling, and then use some sort of USB isolator, or otherwise put isolation on an intermediate digital step like S/PDIF or I2S.

>>2593250
>Do you mean using your sound card?
I was more thinking of some kind of USB input device with buffering, signal handling, ADC and isolation and stuff. Then let the PC display and mangle the data.

>>2593236
No reason you wouldn’t be able to use a sony ps3/4/5 as a scope, as long as the USB was fast enough. Probably USB 2.0 is good enough for an external scope.

>>2589342
your dad was warning you about all the shit he was doing to other people. he's warning you that it happens all the time because he happens all the time to other people.
people who give mega-doomer warnings like this about how "people" will be out to get you are the people who are out to get others, and they know about it because they live it every day.
he's not wrong, it can happen, but he thinks it happens everywhere and all the time only because he is the source of it.
>i could do everything right and still fail
he thought he did everything right and feels like he's failed
>coworkers will try to undermine me at every turn and wish i fail
he is envious of the talent of others relative to him, attempts to being them down to his level, and wishes they would fail.
>try to steal credit and never help you out
he tries to steal credit and refuses to assist others
>work at least 12 hours everyday if i want to buy two meals a day
he is bad enough at his job that he needs to put in 2x the time of other workers to get the same result
>especially difficult trade and everything will always go wrong and i would be blamed
it's difficult for him, things go wrong for him, and he resents being blamed for his lack of skill because he doesn't believe he's at fault
>still wanted me to become an EE
but at least he secretly believes you can do better, that's cute i guess. but he warns you anyway because he doesn't want you to feel that it's a breeze and realize your old man is a stubborn moron.

>>2593250
> 1GS/s A/D chip
I have torn down scopes, and watched signal path a lot.
I’d buy 4 slower A/D chips, phase shift their clocks and drive them with the same or multiplexed signal. You could probably use commodity hdmi mux chips. This is what my tek scope does (not the hdmi mix part tho)

Have you guys looked at modern scopes? They’re so thin now the reviewers have to do the old “does it fall over if I push a button” test.

Probably should have an iPad scope now.

>>2593259
You’re the guy he was warning him about.

>>2593253
480Mb/s, for an 8-but scope, is 60MS/s, a maximum bandwidth of 30MHz. For only one channel, if you use two it drops to 15MHz. That’s on the shittier side of scopes for sure.

>>2593262
Are those 4 then split up as 1 for each channel? If so it’s pretty neat since you’d need analogue MUXs either way.
Are video ADC (e.g. VGA to HDMI) ASICs usable for scopes I wonder? I know I was looking at using video ADCs for an SDR a while back, surprisingly good specs for cheap, but I don’t know what the ENoB was like at maximum sample rates.

>>2593235
Yeah, thinking about it a little more, wire-wrapping the coax cores is a little absurd. My main concern is that the perfboard would add noise. Is it only a concern with strips of copper?

>>2593252
>some kind of USB input device with buffering, signal handling, ADC and isolation and stuff.

great idea.
wonder why nobody thought of it before.

>>2593269
> Are those 4 then split up as 1 for each channel?
Yeah, you can see some scopes are half the rated bandwidth when using 2 channels.
If using, say, 4 channels, the fpgas direct each Of the 4 A/D converters (with their individual slower clocks out of phase) to individual RAM banks; but the processor sees all of banks at the same time, only interleaved. Thats another reason dual port RAM … the kind that is found on PS5 and GPU cards is useful as a commodity to make oscilloscopes simpler/cheaper.

I remember the Sony PS 2 had this expansion cartridge thing at the back, that would have been perfect for a pluggable oscilloscope. I think the used it to add networking though.

>>2593317
> perfboard add noise?
Nope, perfboard won’t add noise. If you surround copper that has active signals with copper that is grounded, that will act as a shield and reduce noise (generally speaking)

>>2593359
Over $200 for a 10 MHz USB scope? Not of my money.
Thats the problem… it’s not even good enough to work on transistor radios.

I put off a project where I wanted to put a ammeter display on my ebike because I felt like too many things would go wrong.
the things that worried me was unsure if the the cheap chinese switching power supply would put noise onto the sensor (TMCS1108A3UQDR), and I feel like the little chinese 8-SOIC pcb can't handle the 42v 15 amps the bike uses (I think I will need to cut a copper pcb panel).
I found this step down power supply that isn't switching, and I think this is a linear power supply, but when I look them up on the internet it always points to linear bench power supplies which I think probably contains a bunch of unrelated info since it's about AC to DC, but I might be wrong.
The listing doesn't give me much information but I can look up the parts easily, but is there any reason to not use this (surely it's not that much more inefficient, is a linear regulator more efficient for 40v to 5v?)
https://www.aliexpress.com/item/1005001403257773.html

>>2593460
actually I would use a mosfet to turn off the ammeter components.

>>2593460
also I think I figured out this is a flyback converter, but I have difficulty figuring out what the real difference between a non isolated converter is, I guess it's just as noisy but isolated and uses more power...

>>2593424
>dual port RAM
Is that an issue if you can interleave the reading and writing to normal RAM? From what I remember, ADCs usually sample somewhat slower than their output data packet rate such that they can spend less than half their time writing. Though that's for ~1MS/s ADCs, no clue what it's like 3 orders of magnitude up the food-chain.

>PS 2
Oh you were being serious about that. It's an interesting idea, same for somehow using a GPU or parts scavenged off it. Considering all the worn-out GPUs and that the chinks make an industry of harvesting ICs off old boards, I wouldn't be surprised to see a bunch of those RAM chips for surprisingly cheap on alibay. Caveat emptor.

>>2593434
10MHz is more or less the maximum nyquist frequency you can get with USB 2 speeds. Actually it's more like 30MHz, but that assumes a perfect anti-aliasing filter, when in reality since you need 54dB of cutoff (for 8 bits) if you're going to end up with some distance between your passband and stopband. It's 100dB/decade or 5 poles of filtration to get that within the 10-30MHz gap, you could reduce that by using a higher frequency ADC and downsampling in firmware, not sure if that would be cheaper or not. I'll have to check out Signal Path or a Dave teardown to see how they're actually made.

If they delta-sigma convert then they might be able to get away with a much less aggressive analogue filter stage, but delta-sigma converters are kinda shitty at high sample rates.

>>2593460
>>2593483
Flyback converters and other isolated converter topologies have the advantage that they don't have any electrical connection from the input to the output. This is useful for safety reasons, in your case it likely doesn't matter at all. LC filters should handle your noise problems, that or using a buck converter to X+2V and then stepping the rest down with a "linear regulator" of some sort. 7805s and such are ok, but a discrete solution (TL431+BJT+capacitor) would be better for high frequencies.

>>2593424
If you used an FX3 instead of an FPGA you could shuttle:
>5Gb/s = 625MS/s = less than 312MHz of bandwidth
That's bandwidth for a single channel, which is pretty decent. Thing is, can you shuttle ADC data to the FX3's 200MHz ARM926EJ core fast enough for constant sampling without just using internal RAM buffering? Using its 100MHz GPIF (version 2) and all 32 bits of its data bus (four interleaved 8-bit ADCs) you can still only get 3.2Gb/s, so I guess that 5GB/s is only for directly out of RAM. So in reality it would be:
>3.2Gb/s = 400MS/s = less than 200MHz of bandwidth
Scale that down to 100MHz bandwidth for 160dB/decade and you arrive at the 100MHz specs of the so-called 1GS/s scopes. Not sure how you could get an 8 pole filter operating at such high frequencies though.

>>2593262
Is an analog switch for every channel really needed when you're using multiple ADC chips to sample a single input? Couldn't i just connect all the ADC inputs to the input signal directly?

>>2593542
But then you don't get higher speeds when running only 2 or 1 channel.

>>2593542
The analog muxes are what allow you to sample multiple channels in the first place. A 1GS/s scope is usually just 1GS/s when operating as one channel, when on two channels they're 500MS/s, and when on four they're 250MS/s.

>>2593546
Oscilloscopes aside, if I wanted to create a device to sample a signal using multiple ADCs in rapid succession, should I have analog switches so that only a single ADC is connected to the input signal when sampling or is that excessive and I should just connect all the ADC inputs together directly to the input
Not really looking to make anything like this, just kinda curious

ADC resistance is usually so high and not varying it would not matter. But your "multiple" adcs probably run in the same clock, you can't weave them like that

>>2593252
stay the fuck away from digital if you value your sanity

>>2593564
> multiple ADCs
Yeah, basically. For simplicity, everything after the ADC runs independently with it’s own clocks.
>>2593489
> dual port ram
you could have it alternate read/writes, but this is a place where I’d want to use video RAM for simplicity and not needing wait states and whatnot.
> 10MHz max with USB.
Simplistically yeah, but in theory, with an advanced enough digital “scope” side, you could send a picture of the waveform. Or send GPU commands to draw the waveform itself to reduce the bandwidth… just some ideas, stopping short of computing the bezier control points of the waveform and sending that. absolutely hate the idea of bit bashing things.
>>2593491
> FX3
Those are expensive chips!
If you have dual port RAM, I’d be using DMA, not into ARM. That interface logic should be simple, you could use a tiny FPGA or a CPLD, one per “channel”

Speaking of FX3, thats another thing that has shitloads of bandwidth and A/D action: digital (video) cameras. If you could feed the custom camera ASIC a stream of 8-bit A/D values and it gives you the raw image values, you could pick those up and do something with them. Don’t know haw cameras and the cmos sensors really work though.

>>2593681
The sony FX3 camera is a 10-bit ADC I think, so there is an aggregate speed of 14.4 GHz somewhere (or 1.4 GS/s) which is, like, a 60 or 70 MHz scope.

>>2593359
>great idea.
Thank you.
>wonder why nobody thought of it before.
Those are overpriced and under whelming.

>>2593489
>10MHz is more or less the maximum nyquist frequency you can get with USB 2 speeds
don't scopes use mixers to downconvert high frequency signals anyways? making the entire internal signal path at VHF/UHF sounds retarded.

>>2593489
how much would this pcb cost to print and put just the chip ($10) on?

>>2593778
bout tree fiddy

>>2593778
whoops didn't mean to reply...
Anyways,
>>2593460
I think I am just going to use a separate battery for the sensor and a flashlight.

>>2593747
No, I think that's the realm of a VNA, or at least an RF scope. 1GS/s means 1GS/s.

>>2593778
You'd make some modifications to make it more friendly towards being automatically soldered, like replacing the wire hooks with large plated holes, and replacing those on-wire chokes (if that's what they really are) with SMD chokes. Board cost would be fuck-all, check what a 2-layer 5cmx5cm board would cost from JLC. Leaded solder coating would be fine.

>>2593874
>1GS/s means 1GS/s.
I don't know or care what that means. What are the downsides of downconversion? Phase relations?

>>2593992
You're right, he doesn't understand frequency mixing/multiply and is conflating sample rate with the Nyquist frequency of a input signal which could be arbitrarily scaled

>>2593992
>I don't know or care what that means
It means a scope advertised as 1GS/s is actually making 1GS/s = 1 billion samples per second. The digital pipeline is funnelling 1 billion samples every second through into RAM for pickup by the display driver. They're not faking it by just sampling a narrower bandwidth at high frequencies only, because then the sample rate wouldn't be advertised as 1GS/s.
In the case of a shitty 10MHz USB scope it's probably 100MS/s.

>What are the downsides of downconversion? Phase relations?
That you only see what's happening at a narrow bandwidth. What if you have important frequency components at 10MHz and 50MHz? If you're sampling with a bandwidth of 40MHz (e.g. 100-200MS/s) then you'll only be able to see one of those two important frequency ranges at once. In the time domain, this will look like a significant distortion. The low frequency and DC components of a given signal are usually not something to ignore when you're probing a circuit. For radio it's fine, hence why you see downconversion frequently used for RF uses, especially in SDRs.

I think phase relations are still preserved if you properly sample both I and Q signals, which you need to do anyway in order to properly recreate the input signal. Though this does mean you need two mixers and ADCs sampling for each channel.

Is 3V3 the cooler version of 3.3V?

How soon until AI replaces all software including EDAs etc? Imagine most of the knowledge people have accumulated over decades will become obsolete. You will just type: "create a schematic and a PCB of a certain device" and then make corrections as needed by typing instructions. Probably 2-3 years.

>>2594048
> AI will replace x jobs in y years.
What most people call AI now is an on-line, guided, statistical word prediction system. It’s just the A without the I.

We’ve been working on routing algorithms and rules based systems since the 60’s. Nothing has changed. What you generally want is an optimal routing solution, not AI generated circuit diarrhea.

With AI, shit in = shit out. If you’re training your model with crap layouts found on the internet and/or chinese clones it’s going to be even worse.

I imagine jlc pcb and pcbway offer cheap boards so the ccp can more easily clone devices since they’re giving them the design, and, in some cases, the components. The can have them… theres a huge proportion of layouts that involve dick and balls depictions in copper. The AI produced by this set will be retarded and gay.

>>2594038
That’s the euro way, i think you see that in elektor and whatnot. Their rectangular resistors are dumb, but 4R7 and whatnot is hard to find fault with, although it’s not SI and thus illegitimate.

>>2594063
>With AI, shit in = shit out
They're not just bounded by their training data. There are architectures that allow neural networks to produce better outputs than the training data, natural selection and gradient descent are some examples. The important thing is being able to apply a reward function to the new combination of variables to see if it performs better or worse, in the case of EDA that would mean simulation. There was a recent paper by some tech giants about replacing human feedback in a training process (as was done to GPT3 to make chatGPT) with an automated system, which is probably applicable here too.

Honestly I think spice-like simulation is going to be replaced with neural networks before EDA is. It's a more straightforward task and very easy to train with enough spice processing power. Throw thermal simulation in too. These PINNs or "Physics Informed Neural Networks" are a quickly growing field, first for replacing traditional fabric, fluid, or light transportation calculations for computer games and cinema, but probably also for speeding up computationally intensive work in professional environments. Same for the mechanical simulations you get in mechanical CAD.

Once electrical and thermal simulations are cheaper, then the economics of training an AI to design a circuit and any required code to perform a task given in text should be even more favourable.

>routing algorithms and rules based systems
I think he means more a partially-automated engineering workflow like what AI coding is. Tell GPT3 to make a webpage with a search bar in the middle of a blue ellipse with social media links in a dynamic taskbar, and you'll get HTML code out that does almost exactly that. You still have to go through it manually to ensure it works properly, and there are definitely things that it can get stuck on (e.g. python 2 vs 3) but that's just the result from an unspecialised text predictor. More concentrated training and we'll have gold within a decade

>>2594080
> PINNs
We already have the physics. ChatGPT can’t even do math. Adding the “physics” to a neural net to make its simulation less wrong only attempts to add plausibility to bullshit created to generate funding. Makes as much sense as new “blockchain spice modelling”
> It’s coming real soon now ™
So is quantum computing and fusion. They needed something to replace blockchain and crypto.

> AI coding
I work in medical embedded systems. I’ve seen the code it generates; sometimes you can even find the original code snippets that it coped from, usually some guy from india’s tutorial.

They’re going to kill people, guaranteed.

>>2594090
Neural networks are already good enough to replace ray-tracing and fluid physics for computer games. The human eye can't tell the difference. You simply iterate a properly architected neural network on existing physics simulators in order to perform the same task faster, and a well-trained network won't deviate even on highly novel scenarios or with novel iteration counts. Fluid dynamics though is probably the more important thing to speed up.

ChatGPT is just a network trained to complete human text, with some extra human-driven post-training to make its results more palettable. Completing code is just a byproduct that's doable because people comment and describe their code to a wide extent. Obviously it's not going to be perfect at that, nor at calculating anything rigorous, because there's no ground-truth calculations or code compilations built into its reward function. Comparing that to a network explicitly trained with simulated scenarios is disingenuous.

>>2594102
> human eye can’t tell the difference
I have bad news, I think we can. Ymmv.

Omg I can't get this thing to work
I got a back ache from soldering/desoldering.
It's supposed to be a full bridge rectifier.

>>2594110
nice reading comprehension there, comparing a text-to-image generator with a 3d scene rendering technique, sure showed me there

see here:
https://developer.nvidia.com/blog/nvidia-research-learning-and-rendering-dynamic-global-illumination-with-one-tiny-neural-network-in-real-time/
conventional real-time ray-tracing is actually bested by this sort of neural net that incorporates global illumination far faster than the brute-force method

>>2594113
the sides are ac, top is positive, bottom is negative, right? what's the result, no voltage or shorting? what's the ac source? is the diode voltage drop showing up correctly?

>>2594115
The result is no voltage

>>2594116
then check the diodes

>>2594116
Oh and the source is one of these things. It claims to generate 400kv but the arc is like half a cm so I think around 15kv.

>>2594120
are your diodes rated for 15kv?
hint: the answer starts with "n" and ends with "o"
same as the answer to "will my multimeter be fine after measuring this voltage"

buy some silicon stack diodes and put them sufficiently in series or buy an appropriate tube rectifier

>>2594121
I think they're rated for 15kv they're 2cl series diodes... But I tested them and yeah all four of them are shorted. When I was soldering them they got really hot so I think that's why they broke.

Is there any way to identify Melf diodes like these?
I can check that they're not zeners by removing them and putting reverse voltage across them with a low current limit and check they don't conduct (up as far as 30V, the maximum voltage on the board).
Also the zener MELFs I've come across usually have a yellow band on them.

The lower ones here with the gray band seem to have a lower forward drop (0.25) than the top two with the black band (0.6)
Is it safe to assume that the gray ones are just schottky diodes?

Got offered a job as a pcb board technician (diagnose and repair) for $18/h, 3 days a week. Seems like the pays a bit meh, I live in a fairly expensive area. What do you think, would you take the job?

>>2594128
Have you done debug and repair before (as a job, not just at home)?

If not, it's a good way to get some experience, always looks good on your CV

>>2594128
Meh sounds about right. Is that in the us?
If it was 5 days a week it'd be better.

>>2594115
> far faster than brute force
NRC was Faster than generic tensor flow, yes; faster than the reference images (which took minutes) yes. Those are straw men. But it’s 3 times slower than the existing method (DDGI) should someone actually read the paper instead of just the insanely long url. Maybe AI could help them shorten it, they should probably learn to walk before they run. Also, i think nvidia serves that site with a dial up modem.

I’m going out to take some videos of the moon with my samsung s23 ultra. Last time I clearly saw neil armstrong waving at me when I zoomed in.

>>2594126
> Got MELF?
Can you power on the board? Might be faster. The zeners will likely be zenering at their voltage.
I usually just test them with a big resistor.
Yeah, .3v are probably schottky.

Does anybody any diodes that can handle 100kv?
Im not sure but I think the good one I had left shorted too. These shits are no good.

>>2594034
>What if you have important frequency components at 10MHz and 50MHz?
then I sure as shit won't be seeing them at 1ms/div. let me guess, you "need" one of those fancy $10k scopes that does everything? we're talking about sub-$100 chinkshit for noobs here.

>>2594131
nah aus but i converted to usd to aide conversation. i could earn 2 dollars less and work at a grocery store so i dont know man
>>2594130
not really, i dont really have any qualifications in the field either, but im working towards them.

>>2594159
Oh no I know. It's terrible. I meant meh sounds about right. Not. Meh, sounds about right.

I don't understand common-base bjt at all

Why did nobody tell me I can connect diodes in parallel for higher voltage rating.

>>2594192
Read more books.

What would the design of the lowest noise power supply look like? I know the start would probably look like:

transformer -> rectifier -> capacitor -> linear regulator

what would come next?

and how would such a low noise power supply compare to say just using a LiFePO4 battery with a linear regulator?

>>2594192
>connect diodes in parallel for higher voltage rating
How would this work? Did you mean in series?

>>2594199
>what would come next?

a multiplicity of (blueberry) pi filters, and an Inception style faraday cage inside another faraday cage, etc.

>>2594203
Oh right I think parallel is for amps not volts. My mistake.

>>2594203
>Did you mean in series?

only works if you equalize the reverse voltage.
otherwise, the chain breaks down as the weakest element in the string shorts out, then the next, etc.

>>2594139
yeah, it's called a spark gap

>>2594213
So there should be a parallel resistor for each diode?

Fucking TI

>>2589612
>>2589746
Retards

>>2594350
Fucking. Texas. Instruments.

It is amazing that no matter how slow this thread is moving, it will eventually hit the bump limit while you are not paying attention, and next thing you know it is gone and you will need to find a new one. Basically this a perfect model of a human life. 300 messages is about 2-3 years before retirement.

>>2594378
It's slower than usual because tranny banny bo-janny, banana fanna fo-fanny, me mi moe-MAN-y.

Tranny.

>>2594110
You're underestimating it. Don't. Humans can't even draw realistically looking hands without it looking like a drawing. Fight AI garbage with all you can. Though I don't know how, big corps will control us as always, just much better.

On a scale from 1 to 10 how hard is it to make schematic for a flight controller for a drone, if I have just basic understanding and watched Phil's Lab and Robert Feranec videos about schematics creation?

>>2594408
3.50

>>2594414
What about pcb?

>>2594418
That's more difficult because RF voodoo. You'll have to consult Jobu's Radio Frequency Spirit Guide for the answers to your query.

>>2594199
Probably the battery is the lowest, although different chemistries and construction would vary. I remember that the old carbon-style resistors were noisy. Transistors and diodes are noisy, and zener diodes are used to generate noise and random numbers. Switching power supplies are generally gawdawful.
Transformers might give you 60Hz hum, is that noise to you? You can design a linear regulator to be now noise, which usually means paralleling some of the transistors which cancels their noise (somewhat couter intuitively) but it’s rare to see that.
>>2594207
This guy’s got it, low pass filtering. I think for a PSU you’re gonna need big inductors and capacitors.
I collected a bunch of picrel from devices and microwaves which I imagine help lower noise. I randomly stick them into projects.

>>2594421
No no there's no RF, it's separate off the shelf pcb. On a flight controller you will have something like STM32F4, peripherals and sensors like baro, IMU etc.

>>2594430
In that case it'll be easy. Basically layout and routing.

>>2594209
> parallel diodes increase amps
Not so fast. Diodes have a negative tempco, so one diode will run away and blow up, and the others will soon follow. You have to put resistors in series with each diode, and then parallel each resistor-diode combo.

These kind of modules. Is this for some known standardized rack format or it's just arbitrary but all the same size?

>>2594353
I think that bridged short circuit across Q2 is suboptimal

When the intern was making it, they probably used 30 ga wire and the wire evaporated when q1 turned on, and they didn’t notice and declared “all good”

>>2594445
Whenever I see 53 mm I think of DIN rails.

>>2594445
>>2594452

panel mount

>>2594445
whenever i see DIN rails i think about stubbing my toe
i was reading a catalog of DIN-mount shit when i stubbed my toe

>>2594480
>How a tech aversion starts.

>>2594426
>60Hz hum, is that noise
yes I would like to eliminate any ripple from the 60Hz mains, as well as any other noise that may happen

>You can design a linear regulator to be now noise
what about connecting several linear regs in series? so say to get a 5V source I'd go from the rectified and smoothed mains, to 12V, then to 7V, and then to 5V; would that reduce ripple and noise, or make it worse?

>Switching power supplies are generally gawdawful.
yeah would definitely not be using a switching PSU

>big inductors and capacitors.
good idea

>>2594207
cool, thanks

>>2594123
Silicon stack diodes will have a longer body for isolation purposes. Check the forward voltage using a resistor and some sort of power source, a 15kV diode should give a forward voltage of 30VDC or so.

>>2594624
I love those LCSC components photos. All those mouser and digikey pictures suck dick comparing to these.

>>2594602
> regs in series?
I was talking about transistors in parallel, I think. It’s an audiophile thing that involves deep transistor noise theory. Picrel is kind of what I think they were doing, except this was designed to raise the current with pass transistors rather than lower the noise. Ignore the euro stuff, didn’t have time to draw it out myself.

>>2588696
I am a system engineer working in oceanography. There are a lot of one-off or small production run systems that are used in data or sample collection in the field. It's diverse; satellite modems, hydrophones, embedded systems, robotics are just some of the systems I work on.

>>2592989
Fusion360 incorporated Eagle into it's code. You can use it all for free on a hobbyists license, renewed annually. Or KiCAD is FOSS for your design needs.

Found a cool-looking fan at a thrift store today, and it actually used a freaking 18650 battery. But the stupid thing had a USB charge port that kept dodging into the case.
After taking it apart and poking around, I noticed that the battery connections were reversed. What the fuck, Chinkistan. Anyhow it turned out that not only was there bad soldering work on the USB connector that didn't solder it down to the board, it also was missing a flanged screw to hold the board in place.
Complete luck that they had fucked up the USB connection badly enough that it didn't try to charge that big battery backwards.

>>2593147
Yes that is common and normal for those holes to have solder in them. It is from the step in the manufacturing process when the board goes through the wave soldering line. Since the holes are tinned through holes and are exposed and not masked, they will get wetted by the solder wave as the board passes through it. The vias, which tend to be much smaller diameter, miss getting whetted because their tinning is usually far less exposed and the surface tension of the molten solder is not strong enough to wet the via and fill it in.

>>2594602
don't forget the wooden knobs

>>2593359
I have a couple 4-ch USB picoscopes at work that were bought with some remaining year-end funds. They get used for projects in my lab where I'm not picky about high-resolution or high-precision. They are really great for directly logging data to a PC. Far better and more economical than fiddle-fucking around with buying LabView or a NI license, or setting up a LAN, GPIB, or RS-232.

I just want to connect the USB, run the scope software, and log the fucking data directly. No bullshit, no separate piece of intermediary hard/software, no dongles, no license server, just stream my fucking data straight to disk.

>>2594199
Check out Vicor and Analog Devices info. They have free resources, documents, tutorials, and whole design programs to help with this. I stumbled across them last year when troubleshooting a COTS system that a vendor just placed a stand-alone DC-DC converter in without any I/O filters and it was causing problems.

>>2594719
yeah im not an audiophile.
>$485
this is a money laundering scheme right? fuck I hope it is

I'm a third worlder and i refuse to pay 300$ for a shitty 50MHz scope
Might as well use a 5$ USB dev board as an oscilloscope.

>>2594704
Surprised the charge circuit didn't get killed by the reverse voltage.

>>2594803
yes sambibi, reject the oscillojew and build your own nigroscope

>>2594803
https://www.youtube.com/watch?v=6oxiaeXYja8

Is it possible to add an sata port to a shitty acer laptop board? It's just recycled everything, there's a spot in the case for a 2,5hdd and there should be connections somewhat ready in the pcb.

>>2594815
Chances are the supporting components aren't there, but maybe there's vacant footprints for them. Got a schematic+boardview that include the unpopulated parts? You'd probably need to change the bios too.

>an sata
do you pronounce sata: "ess ay tee ay"?

>>2594817
It's pretty hard to find a good boardview or schematic of this, that pic is the best and i think the one on the left between cn18 and pj15 (it's so fucking blurry I can't read them clearly) is the flat cable spot for the sata.

>an sata
No, it's an typo

>>2594815
>an sata

Do "faster" buck-boost regulators (or any kind of non-isolated switching regulators) have a "faster" response time than slower ones?
For example will a 1MHz buck-boost regulator handle large load transients better than a 50KHz one? Or is the switching frequency unrelated to actual control loop and I just need to minimise the capacitance on the feedback line

>>2594815
>add an sata port to a shitty acer laptop board?

what's wrong with using the M.2 slot?

of course, they make SATA to USB adapters for a few bucks.
i install Win8.1-to-go on them, so I can carry my OS with all my favorite apps, games, bookmarks, passwords, email accts, etc, in my shirt pocket, and use it on any virtually any computer anywhere.

>>2594877
I don't think there is an m2 slot either

>>2594807
>killed by the reverse voltage
Hard to do that when you can't get any charge voltage at all into a USB micro port that refuses to connect. Did you even read what you replied to? Your English word to learn today is "luck".

>>2594881
>I don't think there is an m2 slot either

oh, what's this then?
looks a lot like an M.2 Nvme.
could also be an M.2 sata, even though it only has 1 notch. (it's not normal but possible)

>>2594885
looks like a m.2 m-key slot.

>>2594891

right.
on Kingston's website you can type in the model of you computer, and they give you a list of all the memory products that Kingston sells for it.
it's usu pretty accurate, so you have a solid understanding of all the RAM and storage possibilities you have under the hood.
https://www.cdw.com/content/cdw/en/product-finders/kingston-memory-finder.html

>>2594885
Sorry didn't notice that one

anyone know what these balls with dots are or their values..they are causing no end of grief and I'm stuck till I can replace them

>>2594877
aren't those things inherently shit? i vaguely remember USB being orders of magnitude slower than SATA

>>2595110
It's not ideal. Bandwidth will be worse, and in my opinion USB is never a stable connection. If you use one, make sure you get an adapter with USAP support.

>>2594883
Not like the lithium ion battery comes from the factory at 0V. I've never seen one in a new product at less than 3V. I assume the battery was inside the fan because it was at a thrift store and probably not in its box, but who can say. Maybe nobody put the battery in after seeing the dodgy USB port.

Is this correct? Thanks in advance

>>2595220
Looks wrong somehow. I see at least one leg has to be cut, and since you didn't that means you didn't run the check. Kinda looks off.

>>2595231
Ah thanks. Yes, I did miss that leg. The only thing I'm unsure about is pin 7 and pin 5. It makes sense that they both get 12V right? Updated picture and included voltage regulator circuit

Babby tier question, but how do you measure the voltage of a component on a HV AC circuit board? Do you just put one lead to the positive of what you're measuring and the other one just goes to ground?

>>2595110
>aren't those things inherently shit?

no, they work great.
you can plug in a HDD and be running a brand new operating system in like 30 secs.
as for speed, SATA is 6Gb/s and USB3 is 4.8Gb/s so no big diff.

>>2595269
>It makes sense that they both get 12V right?

nothing about that relay makes sense.
when it clicks on, it connects +5V to pin 2 but there's nothing on on pin 2
when it's off, it connects 2 and 3, but there's nothing on 2, so your LED never lights.

things are even more retarded on pins 5,6,7.
you have 12V going directly to the terminal block, so what's the relay doing? NOTHING.
when it's both on and off, it connects +12V to pin 6, but there's NOTHING on pin6.

>>2595363
>one lead to the positive ... and the other one just goes to ground?

this kinda works on DC, but not AC.
on DC, you take a measurement on each side to ground, then subtract to get voltage across component.
the correct way, on both AC and DC, is to measure across the 2 terminals of the component.

>>2595269
>It makes sense that they both get 12V right?

nothing about that relay makes sense.
when it clicks on, it connects +5V to pin 2 but there's nothing on on pin 2.
when it's off, it connects 2 and 3, but there's nothing on 2, so your LED never lights.

things are even more retarded on pins 5,6,7.
you have 12V going directly to the terminal block, so what's the relay doing? NOTHING.
when it's off it connects 6 and 7, but there's nothing on 6.
when it's on it connects 5 and 7, but 5 and 7 are already shorted.

>>2595140
The "wrong" wiring was relative to the polarity molded into the plastic of the battery compartment. They might have simply installed the battery to match the actual polarity.
At some point after I pulled the battery out, I noticed the molded polarity. I would have put the battery back "wrong" without noticing, except that I had my meter out and was checking voltages.

>>2591976
>>2592007
Alright so I poked around the board some more but haven't plugged it in yet. Tested the diodes and they all seem to be fine. Also got schematics for the ICs.

IC904 seems to be an AP1510 step-down converter regulator. IC901 pic related is I think a LD7576A PWM controller. Checking the pins though I noticed the ground pin (or any of them for that matter) actually connected to ground. Confirmed this by looking around the chip and didn't see any traces going to anything resembling ground. Idk very strange for it to be wired this way.

Also some more digging online led me to suspect inductors as the source of the noise I could hear. As they warmed up after a while the sound would go away, the inductance would change and everything would work. Is this theory legit?

>>2595404
Thanks. How about this - I'm pretty sure I got it right this time. Famous last words.

>>2595677
If the goal is to switch 12V between the terminal block pins 1 & 3 then this will work.

>>2595677
>pretty sure I got it right this time

looks fine, assuming this is the functionality you want:
- relay OFF: +12V goes to terminal #1
- relay ON: +12V goes to terminal #3 and LED lights up

>>2595677
>>2595693

forgot to add that the relay for the LED isnt really needed.
just wire the led and resistor across the relay coil.
it means you can use a cheaper SPDT relay.

>>2595691
>>2595693
>>2595697

Thanks

>>2595714
np

>>2595390
>USB3 is 4.8Gb/s
what about USB2? iirc some older systems have spotty support for 3
otherwise, neat

>>2588633
Dipshit here.
I have pic related.
>Ferrite Core, dumbbell shape with unkown specs, dimension in pic rel.
>Ceramic Cap, 0.1uF (104 label on cap)
>Two 12v white / yellowish LEDs, anode to cathode and vice versa
How the Fuck do I find out what core it is so I can order new ones and build this shit? The Core is being used to transfer power from coild beneath.
I assume the LEDs are setup in this way to keep the LEDs on 100% of the time because it is AC power but I'm not sure.

>>2595748
any transformer core should work. specific types are only needed for high Q resonators, high frequency, and high power circuits, of which this circuit looks like neither.
anything with high μ should work. FT-43 is a common material for that.

>>2595754
Thanks Anon. What ballpark µ are we talking? Also pic related is what it actually looks like, seems to be a DR type core?

>>2595766
>LED end

I want to build battery powered stair light sensitive to movement.
Does it make sense to make basic CCCV driver out of arduino to drive power leds ?
I intend to slap two 18650 bats there and I am bit worried about safety. I arduino reliable to drive such circuit for years without burning my house down (dying randomly shorting the bats via transistor) ?
What safety elements should I include besides simple fuse ?

>>2595810
Why the Fuck would you use an arduino for CC-CV that.
Use a li-ion battery management system (BMD) for battery safety.
https://www.youtube.com/watch?v=rT-1gvkFj60

>>2595816
>Why the Fuck would you use an arduino for CC-CV
I want to have proper led driver that won't burn half power on some current limiting resistor since it's bat. operated
Also I want nice features like slow fade in/out not to be jumpscarry during night and there isn't much drivers that do that. Plus there will be also PIR sensor and some indication of bat. state so I want to use uC right away instead of trying to implement it fully by basic components

will include the BMS for sure, that's a good call

I'm working on VLF and see my fridge is producing some RF noise flooding the home grid.
Could the use of ferrites kill this ?
Is there maybe some filters to put in between the wall plug ?

>>2595766
high. Consider your source impedance, input frequency, and the impedence of the transformer at that frequency.
The transformer's impedence just needs to be high enough for there to be no significant voltage drop from the voltage source.
Honestly, a steel nail would probably work fine.

>>2595748
>I assume the LEDs are setup in this way to keep the LEDs on 100% of the time
actually, what the fuck is the application of that circuit? Is there really just one coil, no primary+secondary? Did you find it on the ground?
It looks like a physics lab demonstration of how an LC resonant tank works.

>>2595879
>Consider your source impedance, input frequency, and the impedence of the transformer at that frequency.
I know none of those.
>The transformer's impedence just needs to be high enough for there to be no significant voltage drop from the voltage source.
Alright. But what about saturation?
>Honestly, a steel nail would probably work fine.
Lol, would be too large.
>actually, what the fuck is the application of that circuit?
Don't laugh, but it's plastic candles with LEDs that light up when put in the right spot ... I work at an escape room and fix all the shit people break there and sometimes I have no fucking clue how because nothing is documented. At all. It's all a guessing game. I know, it's retarded.
>Is there really just one coil, no primary+secondary?
The circuit diagram is only the candle half. The "power" side is inside an "altar" but I haven't taken a closer look at it because it is fucking ogre. I would post pictures, if I had taken them the last time I took that POS apart.
>Did you find it on the ground?
Pic related. Someone fucking broke it and it's my job to fix it.
Actually, I'm designing, 3d printing and assembling completely new "candles" so we can have new ones with a few hours notice if this ever happens again. I'm doing this to everything. But I'll get a nice stack of cash for it.
>It looks like a physics lab demonstration of how an LC resonant tank works.
Worse. It was built by gopniks. The entire fucking escape room.

another dumb question about linear regulator circuits. i try drawing this circuit in ltspice and it won't work: https://youtu.be/_CFIovMkRyg?t=1310

why?

>>2595647
It won't be connected to ground, it will probably be connected across rectified mains; e.g. across C907. Its negative leg will probably be tied to C907's negative lead. You can see on the underside, right after the jumper from C907, there's a bunch of traces all spreading out, which looks just like a "star ground". I think I can follow pin 4 around and back to the star. And pin 6 is probably going underneath and to the right, maybe to the left also. I'm guessing it's both an off-line zener dropper and an auxiliary winding based power source.

As for inductors producing noise, yeah you're right they are usually the source of buzzing, the other one being arcing and that's indicative of a pretty bad failure. But that doesn't mean a failure in the inductor is the source of the issue. In fact, because it's buzzing you can be pretty sure that the wire is still intact. Often a PSU won't buzz much normally, only once the converter chip fails by sending it the wrong duty cycle or frequency. The inductance itself likely isn't changing significantly, though thermal expansion may be why the windings are looser cold than warm.

>>2595766
Try to estimate the thickness and mass or volume of the copper windings. If you can deduce that it's 40awg for example, then you can calculate from its dimensions how many turns there were, and hence estimate the inductance assuming a common ferrite core material.

>>2595823
Arduino-based SMPS is kinda just worse than using a dedicated SMPS controlling chip. Like the good old TL494, which has the capability for two seperate feedback loops, so you could implement CC/CV pretty easily. May still need a current sense amplifier though.

>>2595913
Reminds me of those magnetic floating ornaments, I think they use a similar method to get lights on the floating part.

>>2595915
well, i mean, it will work. but the output is limited by the op amp supply rails less approximately one diode voltage drop. yet the schematic in the video works perfectly IRL. why isn't it working in ltspice?

>>2595915
Output can't be higher than OP+ since Q2's collector is the only current source for Q1's base. Feed Q2 VCC instead.

>>2595918
how does the schematic in his video work IRL? >>2595917 or did i mess up drawing the schematic like an complete idiot?

>>2595916
>Try to estimate the thickness and mass or volume of the copper windings
I dond't have a micrometer on hand, would've done so already if I did.
I should get me one of those ...
>>2595917
They in fact do not float. They just sit inside those tubes and press a microswitch to close a circuit. If you insert all of them in the right order, you close the circuit which also powers the coils for the LEDs. It's a fucking nightmare.

>>2595917 >>2595921
Sorry, second reply was also meant for >>2595916

>>2595920
Didn't watch the video. I'm not too sure either. Having a voltage higher than your op-amp rails being pulled up at your op-amp inputs doesn't sound like a safe practice. It would have made more sense if the op-amps were open-collector or were otherwise powering NPNs, though that could mess with your stability. Would also work if he flipped the op-amp inputs and used a PNP output stage instead, which is also bad for stability. I'll watch the video now.

>>2595921
>I dond't have a micrometer on hand
Get some sticky tape and stack a bunch of pieces next to each other. After 10 or 30 you should be able to measure with callipers.
>press a microswitch to close a circuit
Aw, here I was hoping you detected their presence magnetically. Anyhow, that order detecting circuit would be interesting if it were done with discrete logic, though it's probably just a PIC or whatever. Post ogre when you can.

>>2595915
>>2595927
OP+ and OP- should be relative to LOAD, not relative to GND. See ~3:30 timestamp. Though I'm not yet sure how he shifts the current and voltage sense setup.

>>2595931
okay that kind of makes sense, although im not sure how to draw that in ltspice.

>>2595927
>Get some sticky tape and stack a bunch of pieces next to each other. After 10 or 30 you should be able to measure with callipers.
I mean the idea is good, but
>Hand pasting 30 wires thinner than my nutsack hair next to each other onto a piece of tape without leaving any gaps
It will be ogre.
>Aw, here I was hoping you detected their presence magnetically. Anyhow, that order detecting circuit would be interesting if it were done with discrete logic, though it's probably just a PIC or whatever.
I'm ESL. It's not order, it's position. The "order" i.e. which goes in first, is not of importance as it is a serial connection. See pic related, shitty diagram of what what we're looking at. Ground actually goes to a pin of an Arduino 2560 Mega.
>Post ogre when you can.
Let me see if I can find something on my phone. I could post other ogre though. Lots and lots of ogre.

>>2595937
>Lots and lots of ogre.
Not even 4 fucking minutes after I post this, I get sent this. Some dickweed broke the only fucking skull.

I just fucking can't anymore.