Old thread is no longer bumpin' >>3002473>I'm new to electronics. Where to get started?It is an art/science of applying principles to requirements.Find problem, learn principles, design and verify solution, build, test, post results, repeat.Read the datasheet.>Comprehensive list of electronics resources:https://github.com/kitspace/awesome-electronics>Project ideas:https://hackaday.iohttps://instructables.com/tag/type-id/category-technology/https://adafruit.comhttps://makezine.com/category/electronics/>Books:https://libgen.is/>Principles (by increasing skill level):Mims III, Getting Started in ElectronicsGeier, How to Diagnose & Fix Everything ElectronicKybett & Boysen, All New Electronics Self-Teaching GuideScherz & Monk, Practical Electronics for InventorsHorowitz and Hill, The Art of Electronics>Recommended software tools:KiCAD 6+CircuitmakerLogisim Evolution>Recommended Components/equipment:OctopartLCSCeBay/AliExpress sellers, for component assortments/sample kits (caveat emptor)Local independent electronics distributorsladyada.net/library/procure/hobbyist.html>Most relevant YouTube channels:EEVblogW2AEWMoritz Klein>microcontroller specific problems?>>>/diy/mcg>I have junk, what do?Can it run Doom?>consumer product support or PC building?>>>/g/>household/premises wiring?More rules-driven than engineering, try /qtddtot/ or sparky general first>antigravity and/or overunity?>>>/x/
>>3007000Literal page 2 bake? That’s barely half the thread’s full lifetime. It’s a general, not like front page bumping matters at all. Waiting until page 8-10 is how it’s been done for at least a few years.
>>3007000I'm looking for a new Multimeter and I can't decide between the Amazon Commercial 90DM619 and the Kaiweets HT118E.I've also taken a look at the UNI-T UT139C, but that's not available right now.Any meters that I'm missing? Budget is 50€ tops.
>>300847790DM610*Missing my Numpad right now.
>>3007000>>3008491>Diodes pointing towards FB means you get the greater of the two feedback signals, diodes pointing away from FB (wth a pull-up resistors) means you get the lesser of the two feedbacks signals.i see this now (in ltspice.) thanks for saving me a frustratingly stupid board revision.>Even the small amount of ripple that gets through your low-pass filter will be hugely amplified by your error amplifiers, resulting in a bunch of output ripple.are PWM DACs more difficult than i'm perceiving? settling time doesn't really matter to me. 100 khz PWM through a 30K and 100nF RC filter should yield roughly 1.65 mv ripple peak to peak on a 3.3V input. that's close to 11 bits? afaik DACs don't have output ripple but shouldn't this ripple be functionally the same as the precision/accuracy of a 10-11 bit DAC?>Seems like Q1A is a bit superfluousQ1A exists to shut off the charging power path no matter what happens. i selected them to withstand VCC (20V from USB-C.) normal charge termination? shut off charging. buck converter fails and the output rail sees 20V? shut off charging.>If it’s tied to ground in a single-supply circuit, it will clip any negative voltagesi don't want to charge a dead battery since it's unsafe. off-board comparators check for a minimum voltage, like 3.0V for an 18650. a reverse polarity cell would read 0V, as would an absent cell. a dead cell would read <3V. comparators trigger SD LATCH, no current flow can occur because Q1A/Q1B are held off.
>>3008496typo:Q1B exists to shut off the charging power path no matter what happens. i selected them to withstand VCC (20V from USB-C.) normal charge termination? shut off charging. buck converter fails and the output rail sees 20V? shut off charging.Q1A exists to shut off the discharging power path in the case of the IRFP250N blowing up.
>>3008497> IRFP250NWhy not use bipolar, they’re more robust and usually handle around 60 V
>>3008498>Why not use bipolar, they’re more robust and usually handle around 60 Vi have a dozen IRFP250N on hand. i've used them in pic related to 100W and 10A sustained. they should be more than adequate for 10-20W (heat sink limited).
>>3008496>that's close to 11 bitsYeah but the R2R DAC isn’t oscillating by half an LSB thousands of times per second. If your error amplifier gain is like 0dB at the PWM frequency it’s probably not an issue, but I’d definitely calculate that.Q1A won’t shut off charging, only discharging. If your buck converter outputs 20V, you’ll have to catch that in software and shut off Q1B.I guess worst case with that voltage sense amplifier is it starts clipping the signal, so you detect a 0V battery or a backwards battery as the same. But I’d still want to be able to tell the difference between those, and avoid any issues with the amplifier not behaving well close to its negative output rail. I’d want to be able to measure down 2.5V at least, for LFPs and DW01-protected cells.
>>3008501I’m looking at the datasheet, you’ll be in the thermal instability range at anywhere below 45A in the VCCS operating mode. So I’d be cautious.
How does an op-amp work?
>>3008550> how opamp workIt’s like a super-good transistor.The “op” is that you can configure it to do summing, difference, integration, inverting, etc etc ad nauseam with a bit of extra circuitry.The “amp” is that it amplifies with configurable gain.
>>3008550Long-tailed pair (possibly with darlingtons) as an initial differential amplifier, plus a few additional (I think common-emitter) gain stages, followed by a push-pull output stage. The long-tailed pair has a very high effective input impedance, and the push-pull stage has a very low effective output impedance. With all that gain in the middle, any nonlinearities and parasitic behaviour flattens out when you use negative feedback.
This is what I am being taught in college.It's flat out 2 amps and I have calculated the math all other resistors. Am I retarded?
>>3008582Here is another one, one typo means the problem is wrong, even spaces count the problem as wrong and it does not ask for the math. I did it in fractions, not decimals.
>>3008582I don't know why but my screenshots are always sideways when they are vertical in ny gallery. Anyways, I ain't ask for homework, these are already counted against me.
>>3007000Can I run 24v through a 12v KDC4 switch. 12v isnt giving my motors the torque I want and the electronics housing is designed for the kdc4. Now Im reading that kdc4 switches are designed for AC and not really meant to handle more than 12v but im confused because some switches say up to 36v (despite have a 12v label).
>>3008587>>3008583>>3008582It is because you are posting from a phone. Phones assume all their users are retarded, when only most of their users are retarded. Post from a PC. You know, like the one you are taking the picture of? You can screenshot whatever you want using Windows Key + Shift + S. If that is too hard, and you use Google Photos, you can access your phones on the web by going to photos.google.com. You can then download them and use an image viewer like IrfanView to make sure they are rotated properly before posting them here.If you are on an iPhone, well, just ignore everything I just said and deal with the fact that your pictures are sometimes rotated.
>>3008613Usually you can, but it will have it’s current derated.DC has an sustained arcing problem, that’s why the DC current rating is so ridiculously low. There’s probably a formula for it based off the AC rating, but it’s likely non-linear and they can’t print every DC voltage/current rating on it.
>>3008619Is there any way I can figure out the dc/current rating. I realized I forgot to include the current. The switch I have is rated for 12v 40a or 250vac 30a. Im trying to run 24v 8~10a max.
>>3008615Fair
>>3008628At absolute worst it will be 50% of the 12V rating, it’s probably closer to 75%. So 10A will be fine if it’s rated for 40A at 12V. One technique is to find comparable rocker switches on places like DigiKey that give you more thorough datasheets.
>>3008615I actually did try doing a screenshot but the screenshot takes up too much space to be used on 4chan.
>>3008641How to prove you are a Zoomer without outright saying you are a Zoomer.You can change the file format of the image. Use JPG instead of PNG. It takes up much less space. Also, don't take a full screen capture. Use 'snipping area' to only capture the part of the screen you need.
>>3008636Thanks. I was afraid I was going to have change to a different switch model and have to design the housing from scratch.
They don't seem to make pcb-mountable SSRs at the current rating I need (5-6A) plus they're kinda pricey anyway. So I'm thinking of implementing it myself.Is it just an opto and a triac? Just wire the micro into a zero-crossing opto then wire that up to the triac?Do I need to care about zero-crossing on the micro, maybe to align the control signal it emits?
>>3008692If they were to implement SSRs today, they’d probably use two mosfets back-to-back in opposite directions to handle the AC.I don’t think you have to worry about zero crossing that much in this application unless the noise spike is causing problems.Why solid state? Lots of things still use regular relays for switching heating elements (stoves, toaster ovens). Some even manage to attempt to control the relay at the z/c like mr carlson did on his refrigerator to increase the lifespan of the little pcb relay… in addition to the snubber network.
>>3008693>they’d probably use two mosfets back-to-back in opposite directions to handle the ACI've seen this in diagrams too, any advantages to this approach?>I don’t think you have to worry about zero crossing that much in this applicationSpace is pretty tight so I was hoping it'd reduce heat somewhat not having to switch at the peak. I may be misunderstanding this though.>Why solid state?Fast switching to vary power to a heating element since it's heating a very small mass and has to stick closely to a temperature.(Specifically it's for a coffee machine)
>>3008666I wish I was a zoomer lol, grew up without a phone. But good tip.
>>3008696What's growing up with a phone got to do with anything? When I was a kid, phones came in two types: Rotary and Touch-Tone. When smartphones came out I hated them. I only got one because a new job I got in 2014 required one. I still hate them. Laptops and tablets too. 104 keys, a full sized mouse, and at least two big screens is the only way to do it. Gotta have a sound system too. Headphones are junk.>I wish I was a zoomer lolAre you saying you are were born before Windows 95 released yet don't know how to use a computer? Fuck dude, what have you been doing? Not getting ripped and fucking chicks, that's for sure. You are on 4chan.
>>3008692If you want easy-mode, buy a digitally controlled dimmerlink board from rbdimmer.com. Cheaper than aliexpress. You don’t need to care about zero crossing synchronisation, there’s a little MCU that handles that for you, just speak UART or I2C to it and say what dimming percent to set. They make both monolithic boards with a triac and optotriac, and controller boards that have just the MCU on it. That said, my reading suggests they don’t do pulse skipping, only phase-angle control. So good for loads that need high speed, bad for situations where EMI matters.A conventional circuit with zero-crossing is definitely doable yourself, just make sure you’ve got enough timers and interrupt time for it. Maybe the RP2040’s PIO system can handle it for you without interrupting the CPU. If you want to do phase angle control, I believe optotriacs with built-in zero-crossing circuits won’t work, they wait until zero crossing before turning on the output. Just learnt this today.If speed REALLY doesn’t matter, as in lots of full AC cycles between turning on and off, then forget the zero crossing and just switch it on and off open-loop. A zero-crossing optotriac will make for low-transient switching operations.But if you want something faster, especially PID control, then pulse skipping, if not full phase-angle, with a zero-crossing detection circuit is the way to go. They’re pretty easy, just an optocoupler and some diodes and resistors and stuff. It’s basically an established design. The code is the harder part for me.>>3008693I’ve also seen people put a bridge rectifier in series with the AC load and put a single MOSFET in there. Easier to drive, but in both cases they need isolated driving circuits that are more difficult than an optotriac. At least you can just arbitrarily PWM the MOSFETs without caring about zero crossing, but whether you should is another matter. Seems like a recipe for even more EMI than phase-angle control.
>>3008697Based cellphone hater. I’m waiting for an open source hardware dumbphone that’s actually good. Calls, texts, maps, ideally an end-to-end encrypted messaging platform, and maybe an authenticator for 2-factor things. Headphone jack. Can act as a 4G router for your cyberdeck. A week of battery life because it doesn’t do anything in the background, besides polling for messages and calls. Let people write custom executables for it in Fortran.>headphonesYou should take the chifi IEM pill. When the cables break, you replace just the cables. I recommend the Truthear Gate, though lately I got the Salnotes Zero 2 and it’s been great.
How do I make my own drill battery charger if the one that came with my drill craps out? Does it have those microcontroller thingies that would detect you're using a counterfeit one? It's 20V and I just wanna hook it up to a regular 20V power supply
>>3008700Sorry bro, they ain't gonna hold a candle to my 5 speaker surround sound system with full range speakers. When I upgrade my rig, once the AI bubble pops, I'm going to get a sound card that can handle 7 speaker surround. I already have the speakers for it. Earbuds are even worse than headphones. Their tinny little dogshit drivers cannot handle proper sound output. Especially when trying to reproduce wildly different frequencies simultaneously. Headphones are super bad about it and earbuds are worse.At least they don't put a dent in your head. Picture related.
>>3008707Get a CC/CV DC-DC converter module. Probably a buck converter module like an LM2596 (the one with two or three trimpots), run it off a 24V supply. Set to probably 21.0V and some sensible amount of current (less than the converter’s maximum, and less than your 24V adapter’s maximum too), verify the settings with your multimeter. Wire the output up to one of those tool battery adapters. I think you can typically just feed power into its pins without any communication, though I’d probably seek a second opinion from an authority on your battery brand in particular.>>3008709I like having channel separation and no destructive interference between channels in the event my head is 5mm off the centre of the room. Proper IEMs often use multiple types of drivers to cover a wider range of frequencies. Because the required SPL at the driver is so low, the drivers end up being significantly underdriven, with plenty of headroom. If the frequency response is still a bit off, EQ can cover for that so long as you’re not running into distortion. Also I only have two ears, and the vast majority of music is only mixed in stereo anyhow.Now I’d you’re arguing that the phase relationship isn’t accounted for by standard EQs, you’re right. But:>human ears can’t really hear phase offsets in a note, though this isn’t an absolute I suspect there are cases where it might be noticeable>a digital EQ could be designed to compensate phase too, it’s quite possible that such a thing already exists>the phase relationship between multiple speakers that are spatially separated is even more significant and harder to control
>>3008697This was my first phone, so you're gate keeping a person who is already further down the path than you.Anyways, I had the instructor run through the math, this is an electrical engineer, only to figure out that 6/3 is 2.
>>3008700The vacuum tubes are EMP resistant for when the government electrocutes your balls
>>3008724I spend most of my time on video games and movies/TV, so much of it does have surround sound mixes. I'm in a computer chair connected to a mouse and keyboard so I don't have a problem with moving out of the sweet spot. Plus, my amplifiers allow for multiple speaker configurations. If I wanted to, I could just get another set of speakers, mount them in an idea position for music listening only, and then turn a knob on the amp powering the front channels to have them power the 'music' speakers.As for EQs, I listen to so many different genres of music from so many different eras that programming an EQ to be able to handle every album would be a nightmare. Everything from Anamanaguchi to the ZZ Top. Brian Bennett to Chuck Berry. Motörhead to Matthieu Chedid. Then add all the different games, movies, and TV shows I watch? Nah. I'd rather have a system that just sounds good no matter what I'm doing. Plus I like to feel it in my chest when shit blows up. You can't do that with earbuds and you don't even have to have the volume up that high to do it with full sized multi-driver speakers.
>>3008768No you just EQ to make the speakers or IEMs sound neutral (e.g. harman target, or perfectly flat), then listen to the audio as intended by the album. The audio chain between the .mp3 bits and the sound pressure should be transparent, it shouldn’t colour the sound one way or the other. Swapping between EQs each time you listen to a different genre is absurd. If the mix is so bad you have to EQ it differently to make it sound good, then bake a modified frequency response into your .wav so it sounds like god intended without having to fiddle with your EQ settings.
I found a 2tb external hard drive with 30% health. Is it still possible to repair it?
>>3008795Are the platters ok? Are the heads safely parked? The spindle motor/bearing?
>>3008699>rbdimmer.comLooks like cuckflare cucked them out of potential visits. Is "dimmerlink" a generic name or their own product?
>>3008666>Be GenX>Be completely forgottenAlso first half of GenZ is millennial-Lite and better with computers than actual millennials (I use Debian btw).t. 28 y/o comp-sci Zoomer
>>3008819I think it’s their trademark. I haven’t seen an equivalent from any other brand, except for arguably the Kemo M150.Also I’m pretty sure you could replace the variable resistor in a normal analogue dimmer circuit with an LDR and blast it with an LED controlled by a microcontroller, the only issue being its maximum voltage rating. Maybe you could put a few LDRs in series and balance them with TVS diodes in parallel with each. Otherwise, looks like wider diameter photocells have higher voltage ratings, with the 20mm ones being capable of 500V.
>>3008695> mosfets, any advantages to this approach?Modern mosfets (hexfets) have insanely low “on” resistance and need less heatsinking which can be a major space saver.>>3008699> a bridge rectifier in series with the AC load and put a single MOSFET in thereThat’s brilliant, especially if you have some spare bridge rectifiers around… same power, just pulsed DC.
>>3008824Ah, but the first half of Millennials (and the back half of Gen-X) are Xenials!>Xennials are described as having had an analog childhood and a digital young adulthoodWe are a post-computer generation but a pre-internet generation. Early Gen-Xers were already preteenagers/teens when computers started entering the home but many later ones, and early Millennials, grew up with early these computers. Remember, many of those home machines booted up to a BASIC interpreter or had one built in. That started you off in a very different mindset then starting from a GUI. Even business machines, like the IBM and its clones, generally booted to a command line (DOS). Plus all the best games ran in DOS.You had to know how to use a computer to install games. It was a completely different experience to what came later. Check this shit out:https://youtu.be/V-t-zTkNka8?t=90https://www.tiktok.com/@geekjam/video/7397922669213076779https://youtu.be/cioyLQ2O6ycWhen you put a disk/disc into your PC it didn't do shit in DOS. You have to know what the drive letter was, how to list the contents of the directory, start the installer, configure your own sound & graphics settings, maybe even fuck around with extended memory, and then know how to navigate to where you installed the thing. Only then could you play. Lord fucking save you if you needed to setup a boot disk (fuck you Ultima VII).Then came Windows and Direct X and installers became this:https://www.youtube.com/watch?v=TCymoV8jVkwPop in the CD, it would autorun (this guy had to do it manually because modern PCs turn that shit off), chose install, and hit next a bunch. Done. If you were born too late you simply had no idea.Even old consoles didn't hold you hand. No cartridge? Here's a flashing screen. Figure it out, dumbass. Better have it tuned the correct channel and have the switches set correctly. Some of you have no idea what I'm talking about.The PlayStation gave you this:https://youtu.be/r_Ifccgl05A
>>3008824>>3008867Xenials are the technology Precursors. Elder Gods. I've used a rotary phone. I have watched a film... on film using a projector that I operated. I have swapped reel to reel tapes (for music and data). I have programmed a VCR. I have tuned a TV. Not changed a channel, *tuned* each channel button using switches and dials like a DJ. Picture related. No one can do that anymore. Analog TV is dead. I've been on the roof of a house fucking with an antenna. I know why the save icon looks like that because I lived it.Before USB was a glint in Joe Decuir's eye I battled with parallel ports, serial ports, Centronics ports, PS/2 ports (fuck you IBM), and game ports. I used to keep a floppy disk with backup copies of all my computers drivers for when shit hit the fan. I've had to manually configure IRQ ports. Copyright protection used to mean looking up a line in the manual to type in or using a Dial-a-Pirate:https://youtu.be/7tMGNgofeyU Not connecting to the internet. Fancy programs used a thing called a 'dongle' to prevent piracy. No, I'm being serious. That is what it is called. Troubleshooting the office copier that has brought everyone to a standstill? That doesn't even work up a sweat. I can deploy that at the server level using a GPO, preconfigure and lock down the settings so no one can fuck it up, and even make sure the Mongos can see two entries when printing; one for black & white only and one for color, just to make it as simple as possible.Comparing early GenZ to an early Millennial is laughable. I remember when Linux wasn't even a thing. I remember when Windows Updates weren't even a thing either. Shit, we used to reinstall our operating systems once a year just to keep the performance up. I've been using emulators and virtual machines to run different OS's and systems on their non-native hardware longer than you have been alive. I went to a vintage gaming show and bought a T-shirt there back when you wert still in diapers.
>>3008873> Centronics portsUSB C connectors have 24 pins.We’re back baby, we’re back!
Needed to modify a w1099 temperature+humidity control module. By default its humidity regulation would vent all the hot air I’m building up and prevent it from getting up to temperature, so I had to ensure the humidity controlled load would only activate when the heater was off. Next, because this is a 12V module and I want to run it at 24V, I had to add a 12V regulator, linear because I don’t have any 24V capable miniature buck converters lying about. Then that was dissipating too much power, so I swapped the relays for MOSFETs. I was going to have to add an additional BJT to invert the signal going to the FET gate, until I realised the 5V MCU outputs were capable of driving a logic-level power FET (IRLZ44N) by themselves. So I desoldered the onboard BJTs and ran a jumper wire to the FET gates. Hopefully this setup should work more reliably than the original relay design, I’m only switching 2A@24V, but there’s going to be a bit of heat nearby.I might need to blob something in to mitigate vibration, but it feels pretty rigid.
I need some BNC to RCA adapters to use a PVM I picked up with more devices. Is stuff from Hosa (hosatech.com) worth a damn or is it just rebranded Chinese trash like everyone else's shit?
I've decided I want to spend more time learning the actual theory/math behind this shit. I have tinkered and got things to work on my breadboard, but I don't like having such a big knowledge gap. For people who know their shit (even on a smaller scale like just small circuit stuff), how did you best learn it?
>>3008956University courses that recorded on YT, edx and mit. And also free pdf uni textbooks from web. That's how I did it
>>3008956Once you get ohm’s law, KCL/KVL, complex impedences, and the common components (passives, transistors, op-amps), you should have enough of an intuition to get by self-taught. When you need to learn how to make a good feedback loop, you look into control theory. When you need to do some dac or adc work, you look into nyquist sampling theory. When you need to handle high frequencies over significant distances, you look into transmission lines. That’s how I did it, having learnt the basics from a university course.
