/ohm/ - electronics general, corona confinement edition

[Anonymous No.1790136]

>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.

>Project ideas:
http://adafruit.com
http://instructables.com/tag/type-id/category-technology/
http://makezine.com/category/electronics/
Don't ask, roll:
https://github.com/Rocheez/4chan-electronics-challenges/blob/master/list-of-challenges.png.png

>Principles (by increasing skill level):
Mims III, Getting Started in Electronics
Geier, How to Diagnose & Fix Everything Electronic
Kybett & Boysen, All New Electronics Self-Teaching Guide
Scherz & Monk, Practical Electronics for Inventors
Horowitz and Hill, The Art of Electronics

>Design/verification tools:
LTSpice
MicroCap
falstad.com/circuit/circuitjs.html
NI Multisim
CircuitLab
iCircuit for Macs
KiCAD (PCB layout software, v5+ recommended)

>Components/equipment:
Mouser, Digi-Key, Arrow, Newark, LCSC (global)
RS Components (Europe)
eBay/AliExpress sellers, for component assortments/sample kits (caveat emptor)
Local independent electronics distributors
ladyada.net/library/procure/hobbyist.html

>Related YouTube channels:
mjlorton
w2aew
jkgamm041
eevblog
EcProjects
greatscottlab
Photonvids
sdgelectronics
BigClive

>Li+/LiPo batteries
Read this first: http://www.elteconline.com/download/pdf/SAFT-RIC-LI-ION-Safety-Recommendations.pdf
>headphone jack noise
https://youtu.be/n_b_0BWP0mI
>I have junk, what do?
If you have to ask, nothing. Get rid of it.

[Anonymous No.1790144]

this thread's digits brought to you in part by the classic RC4136 quad op amp

[Anonymous No.1790199]

>>1790144
>military temp. range
Based.

[Anonymous No.1790278]

If the LO on a diode ring is used for toggling the diode switches, and needs to be several times higher power than the RF, wouldn't it make more sense for the LO to be a square wave?

[Anonymous No.1790287]

I'm trying to do up a circuit that steps up a 1.5V AA battery to 3V (DC-DC), getting the step-up converter isn't hard, but I'm trying to find a way to smooth and filter it afterward.
The output is going to a relatively sensitive 3V device, is it better to have a 3V step-up or 3.3V to make up for potential voltage loss?

I'm relatively new to circuitry and my Google searches haven't really taught me enough yet, and I'm kind of lost now.

[Anonymous No.1790294]

>>1790278
depends. do you mind making sum and difference frequencies of all those odd harmonics too? that should be ok for RF mixing but could be bad for audio effects

>>1790287
the usual pattern for especially sensitive devices is to follow a switching converter with a low-dropout linear regulator. set the step-up output to the desired output + dropout voltage at the desired current + 500mV or so of margin
of course you should pay due attention to *engineering* your step-up. grab the MC34063 datasheet and use their design equations and advice where applicable. most of the equations apply to any switcher of a given topology. use a low-Rds(on) PMOS for the switch, a Schottky diode, an appropriately fast opamp for the PWM and a proper comparator for the comparator. the faster your switching frequency, the lower your voltage ripple will be (the rate of current change is determined mainly by the inductor but you'll be switching directions more frequently)
and are you really sure you don't want to use one of those 1MHz+ step-up converter blocks in a SOT23-6 package
>inb4 but I don't have any in stock
that was your first mistake

[Anonymous No.1790296]

>>1790287
here's an AAA to 3v0 boost converter design I used recently without issue. if you really care about noise you might consider using a 3.6V boost with as much output capacitance as the controller's datasheet allows and feeding that through an LDO. if you really really care about noise then use multiple AA/AAAs and feed those directly through a low quiescent LDO instead.

unfortunately for you I don't think there are any trustworthy (low quiescent especially) battery boost converters on ali/ebay, hence why I rolled my own when I needed one.

[Anonymous No.1790328]

>>1790144
>military flat package
even more based

>>1790278
>toggling the diode switches
Never heard that before, I assumed the diodes were acting linearly as non-ohmic resistors the whole time.
Also if it's for audio just use a sine from a mono class-D. If it can go before the output amp (RF or audio) then you might want to consider a gilbert cell instead, maybe like an NE612.

[Anonymous No.1790343]

Why don't they just package these things along with an op-amp feedback loop for the LV side? Would make them a lot easier to use.

[Anonymous No.1790362]

>>1790328
aside from the ubiquitous 1N914 that is often called a switching diode, there are also PIN (structure) diodes that are very commonly used in RF systems to cut off signals (with reverse bias) or pass them on (with forward bias). iirc (and I probably don't) the intrinsic layer improves linearity

>>1790343
neat part
the cost/power/speed tradeoff is for the user to make, of course

[Ano̸nymou̸s No.1790363]

>>1790136
test

[Anonymous No.1790366]

Quick question, should I buy SMD ceramics instead of THT? I still use THTs for basically everything else and don't have any other SMD parts, but I figure if I got a big enough size they can fit across 0.1" pitch perfboard and such. Maybe even solder leads to it for breadboard purposes. And for any manhattan boards I do, they'll be extra useful.

[Anonymous No.1790376]

>>1790366
Actually never mind, I was expecting the SMDs to be cheaper but they're not. THT it is. And remember, any THT component can be SMT if you try hard enough. Gotta bust out the DOD-41s, the TOT-92s, and the DIIC-14s!

[Anonymous No.1790388]

>>1790366
>not expecting the SMDs to be cheaper
odd. be sure you're comparing like dielectrics and working voltages
for example, major western brand Kemet SMD https://lcsc.com/product-detail/New-Arrivals_KEMET-C0603C104J5RAC_C490602.html vs lilali hu THT https://lcsc.com/product-detail/Multilayer-Ceramic-Capacitors-MLCC-Leaded_FH-Guangdong-Fenghua-Advanced-Tech-CT4-0805B104K500F3_C84772.html
I don't know if I would consider buying a full reel but I might consider a 1k piece order when the world opens up again

[Anonymous No.1790393]

>>1790388
>dielectrics and working voltages
I just checked Vanxy's two most popular listings, one for 0805s and one for those blobby disc caps. They're both 50V, but I really don't need as high as 50V.

[Anonymous No.1790401]

>>1790328
It was mentioned in w2aew's videos, he always drives the LO at ~1Vppk and the RF at ~200mV, so the LO drives the switches and the RF simply passes through
What about two jfets in series, like pic related?

[Anonymous No.1790402]

>>1790393
oh, try LCSC instead. you could order an entire set of E24 values from 1R0 to 1MΩ in inch 0603 for less than ten items in your cart on ali. plus, corona-chan herself is inspecting all e-packets personally before they go out. for just $10 more you can have DHL shipping, and maybe a kind of cool keyboard-like front-flap box to store components in
class II ceramic caps' values are voltage-dependent. with some dielectrics, you could be getting 80-90% less capacitance at the rated working voltage than at 0V. it's usually a good idea to specify a working dc voltage of no less than 2x the application maximum voltage, to ensure there is enough capacitance when it's needed
0805s might be a bit large to slip between the legs of a DIP. try 0603 instead

>>1790401
multiplying stuff is cool but that's only one quadrant. add 4 more and you have a Gilbert cell

[An̴ony͢m͜ou̵͡s͘ No.1790526]

my heat gun has been stuck in china for weeks now, just deliver it already for fucks sake having to solder smds with an iron is hell

[Anonymous No.1790538]

>>1790526
Weird, my China shipments have been rather fast lately. (I'm in Yurop)

[Á̷n͟o͢ny̵͢ḿ̵̧ous̕ No.1790559]

>>1790538
my other shit is arriving fine, but the one thing i really need is stuck
figures...
also *coof*

[Anonymous No.1790708]

>Why yes, I do buy expensive tools and never build anything with them, how could you tell?

[A̢n͢͜o͏n҉y̷m͢ou̸͘s͜ No.1790745]

>>1790708
>he doesn't have a $600 rework station sitting unused next to a $12 power supply that gets used all the time
not gonna make it in EE

[Anonymous No.1790869]

>paid more for my chink soldering station than for my hitachi oscilloscope

[Anonymous No.1790871]

>>1790745
nigger

[An̢̛̕o̴n̢҉͟ymo̸ų͟s No.1790899]

What is a reason for ever NOT using a schottky diode

[A҉n̨o͘ņymo̷u͠͝s͜͏҉ No.1790900]

>>1790899
fuck ive got aids

[Anonymous No.1790910]

>bike gets stolen or almost stolen
>thinking really hard about how to implement some sort of theft-detection circuit
>never actually make it
>repeat
man that's the third fucking time

[Anonymous No.1790918]

>>1790899
High reverse leakage current. Like an order of magnitude higher than a typical silicon diode. In several applications a few microamps of leakage is often more problematic than you'd think it'd be.

Don't get me sick.

[Anonymous No.1790957]

>>1790918
Not him, but what about for power diodes, bridge rectifiers and the like? Pretty sure all the bridge rectifiers I've seen, even ones that require heat-sinking, have standard silicon diodes within. You'd think that using schottkys would allow for half the power dissipation.

[An̡o͟nymou҉s̴ No.1790966]

>>1790957
i can't speak to the physics behind it but schottkies are typically only available with low reverse voltage ratings and those that can handle mains voltages have high Vf anyway

[Anonymous No.1790967]

>>1790966
Well that makes some sense, thanks.

[Àn̸͡o̢͜n̛y̷̛m͝òus No.1791115]

I'm designing a simple boost converter. My controller IC is a TL2844P which has single totem pole output. In addition to this I want synchronous rectification but this controller was cheap and doesn't have a dedicated driver for that on board. I'm wondering, can I use a half-bridge driver IC like the IRS2104 to generate complimentary waveforms to the main switching MOSFET and the synchronous rectifier?

[Anonymous No.1791130]

>>1790957
Check the reverse voltage ratings of schottkys kek

[Anonymous No.1791134]

I need to place an order from Digikey. What are some ICs/components should I also buy just to have on hand?

[Anonymous No.1791140]

>>1791134
you can never have too many 0402 zero ohm resistors. buy a full reel

[Anonymous No.1791141]

If I TX at the same low frequency of the Speakers, will it create interference on sound output?

Or nothing will happen and music comes out from speakers without any difference?


Also, the pic I chose is randomic, didn't know what to put

[An̨ony̡m̷o̵̴҉u̧s͏ No.1791143]

>>1791134
Can't have too many 100nF capacitors. Every chip needs one.

[Anonymous No.1791155]

>>1790136
>handwired a 2x5 makropad
>uses 2 output/ 5 input pins on pro micro
>cant get it programmed
is there a way to detect which pin sends a LOW signal?
or any other way how i get that thing working without flashing a QMK firmware onto it?
also rollin'

[Anonymous No.1791157]

>>1791141
>If I TX at the same low frequency of the Speakers
At the resonant frequency of one of the crossover circuits?
You mean noise getting through the wires, or wirelessly? If it's through the wires, you shcrould ensure that both your radio's and your stereo's grounds are really solidly connected to the property ground, and that there's plenty of filtration on the mains inputs of both devices. A linear end-stage in your amp could help. If it's wirelessly, then you have to take precautions against wire loops. Like using twisted pair speaker cable (even inside the speaker enclosures), toroidal crossover inductors, maybe even iron shielding around the speaker coils themselves.

But I've no clue which of the changes I've mentioned will actually be significant.

[Anonymous No.1791159]

>>1791155
What, do you think you've accidentally used one of the pins that's used for programming for an IO? Check the pinout.
One of those $7 USB logic analysers is also a great investment, and an arduino on a different computer firing digital inputs back on the serial monitor can be a half-decent logic analyser in a pinch.

[Anonymous No.1791175]

Why do online PCB impedance calculators never take the frequency of the signal into account?
What's the point then?

[Anonymous No.1791177]

>>1791175
Adding to that how do PCB houses control if the required impedance of certain traces have been matched?

[Anonymous No.1791184]

if I put my multimeter on a low setting (lets say mv range) and apply a high voltage that is below the max rating of the multimeter(lets say 200V) will that damage the multimeter?

[Anonymous No.1791188]

>>1791184
shit meter - yes
good meter - no

[Anonymous No.1791196]

How bad are the shipping delays for LCSC?

[Anonymous No.1791214]

>>1791175
Because G is very small and trace resistance is very small (usually) it reduces to srqt(L/C) which is only dependant on geometry of the trace and is constant for the same trace.

[Anonymous No.1791215]

>>1791214
And if you not used to that, remember that circuit is equivalent PER UNIT LENGHT, so even if it a lumped parameter circuit it represents a distributed thing.

[Anonymous No.1791256]

I'm designing my first PCB to send off to JLCPCB, the tutorial I'm following mentions it's important to specify the manufacturer's capabilities in KiCad to make sure the manufacturers can actually produce the PCB without running in to tolerance problems but I'm finding JLCPCB https://jlcpcb.com//capabilities/Capabilities uses different terminology than KiCad and I'm not having much luck trying to guess what each thing means.

Can anybody help me out before I send off a gerber? My PCB isn't doing anything groundbreaking and it's THT and traces are pretty wide so I'm actually tempted to send it off as is.

[Anonymous No.1791258]

>>1791157
No, sorry if I wasn't clear. I meant, for example, my speaker are playing music, and with my VLF transmitter I start to transmit. What happens?
Will it create interferences on speaker audio?

[Anonymous No.1791290]

>>1791258

depends on many factors, so nobody can answer that but you, after you've tried it.

[Anonymous No.1791291]

>>1791258

depends on many factors, so nobody can answer that but you, after you've tried it.
main factors: speaker sensitivity, proximity to antenna, RF power, music volume, etc.

[Anonymous No.1791304]

>>1791214
Why would G be very small? The substrate doesn't conduct at all

[Anonymous No.1791306]

>>1791304
Uh for some stupid reason G is usually given as transimpedance. The image doesn't make it clear. But yes you were right, if it were a impedance.

[Anonymous No.1791307]

>>1791306
Sorry, Conductance*. And the image says it's a conductance.

[Anonymous No.1791308]

>>1791256
Aslong as trace clearance and width matches with theirs the board should work.
As you said its nothing ground breaking.

[Anonymous No.1791310]

>>1791141
Where did you find that picture?
Someone correct me if I'm wrong but L-Pads aren't usually used with woofers. Normally tweeter and midrange is attenuated to match the woofer output.

[Anonymous No.1791324]

I made myself a little clone of this board here https://flashcandy.us/big-nugget-v1.html
Mostly to teach myself KiCad and Hotplate SMD soldering. It seemed to work fine at first but then I noticed the voltage drop under load. It's set to output 5.1V but when I put a 5 Ohm load on it it drops to 4V. The battery voltage and the VSYS voltage remain stable so I suspect the MIC2876 but its datasheet has pic related and I'm basicly using it like the Typical application describes. Anyone got a clue what might be wrong?

[Anonymous No.1791325]

>>1791324
where are you measuring the output voltage? from the board or from the end of a chinese usb cable?

[Anonymous No.1791333]

>>1791308
Great thanks!

[Anonymous No.1791335]

>>1791291
Mmmm, I get it. So more volume in speaker, and less interference?

Also, what's for you the range of frequency we are talking about? Where we are? VLF? Or higher/lower?

[Anonymous No.1791352]

>>1791325
Directly on the board. I don't even have a conector on it. Just thoughholes.

[Anonymous No.1791382]

>>1791258
Are you transmitting AM? Because AM would be detected by a speaker easier than FM or phase modulation.

[Anonymous No.1791403]

Can I position these kind of capacitors in paralel to eachother without them interferfering?

[Anonymous No.1791414]

>>1791403
Electrostatic interference will be nothing, but I couldn't say whether their microphonic properties would lead to sonic coupling of some sort

[Anonymous No.1791418]

>>1791414
It's for audio so I'll go head and place them in 90ª to eachother just in case, thanks

[Anonymous No.1791427]

>>1791155
nice roll, try a CNC machine to test the keys lel
a cheap DMM is a must-have when working on electronics projects. but also if those are encoders at the right of the pic, they might not be in the off position at rest or their onboard pullups might be interfering

>>1791196
if international passenger aviation isn't running, it'll be a while. eBay expects about 2-3 weeks longer from China to the USA. better send via express courier

>>1791256
if it's nothing groundbreaking it's likely you haven't stretched their capabilities at all
one thing you should do for next time is to enter all those design rules (as applicable) into KiCAD's board setup and create a template out of the resulting project. you can call it something like "JLC 2layer regular"
in fact, you should enter all those design rules (as applicable) into KiCAD's board setup so that you can use the design rule checker (ladybug icon in pcbnew) to verify that your board will be manufactured correctly

>>1791352
did you solder the QFN down completely? are your inductor and output cap large enough?

>>1791403
they should be fine side-by-side. the microphonic effect is too weak to bother about, esp if you keep them from touching
you can always replace with greencaps if noise becomes a real issue

[Anonymous No.1791436]

>>1791427
>did you solder the QFN down completely.
Looks to be good. I made 3 of the board and all behave the same way.
>are your inductor and output cap large enough?
Inductor is 1uH, output cap is 2x220uF + 1x0.1uF. I use the exact part numbers as in https://flashcandy.us/big-nugget-v1.html

[Anonymous No.1791541]

>>1791352
1. is that really soldermask under the BQ chip? the die attach pad needs to be soldered on these chips. you should have used the correct standard footprints. when you put big holes in the die attach pad, a hot plate causes solder to wick down the through hole away from the pad. you only want that via if you're going to use a pencil to hand-solder the DAP
2. and is that really an unconnected pin on the MIC?
3. you should try to tighten up the layouts on the switchers. trace through the switch-on and switch-off current paths to find the important loops that you should minimize
4. you should set the Cu layers to be partially transparent. that way, you can see thru the board so you know what's happening on all layers at once
5. I don't see any input caps on the MIC either. sections 6.2 and 6.3 of the MIC datasheet recommend them. I would not treat a 100nF and a general-purpose 220µF electrolytic as adequate decoupling where currents change at amps per microsecond. if you have some larger chip ceramics, you might glom some on near the MIC. don't try to tap in a THT ceramic, long leads are what we need to avoid here
6. >not submitting your design to 4chan for review first

[Anonymous No.1791598]

>>1791382
Interesting? Why that?

[Anonymous No.1791612]

>>1791541
Lets see.
1. No soldermask on the big pad of either IC. The footprint for U1 has been downloaded, for U2 I had to make the footprint myself according to the datasheet. I think tose vias are there for thermal reasons but I see why it might be a problem for hotplate soldering.
2. No. Pin 2 looks unconnected. I laid the trace inwards to the ground pad.
3. I think I did my best to do so.
4. See pic related. Part numbering should match with https://flashcandy.us/src/5V3AUPSR2_Schematic.pdf I just omitted some connectors and 2 LEDs.
5. The input caps for the MIC2876 are the output caps of the BQ25895. About distances. the whole board is just 30 by 50mm and closer together than on the board I copied.

[Anonymous No.1791645]

Hi guys, sorry to be a pleb, just a quick question and I'm off.

I enjoy vaping and have been wrapping coils for a short while now. I use an ohm reader to test them before using them before use, and it uses a single 18650 li-ion.

I only have the one loose battery for its use, my vapes all run 2 batteries in series. My question is this, can I use one of them for the reader before using it again in my vape, or is there any risk associated with discharging it separately before using it in a pair again?

[Anonymous No.1791646]

>>1791612
see? so much nicer
1. ok, I see now
2. I was looking at the airwire at pin 3. I'd have drawn a trace about as wide as the pad out into the copper area so that DRC would recognize it and I could be sure
3. for example, ground to MIC input caps to L2 to U2 to ground. the last segment is pretty long ergo more inductive, also the loop area is large, both of which are undesirable. you can scrape off the solder mask with a dremel, screwdriver, blade, etc. and add the datasheet-recommended chip ceramic capacitor(s), close to the chip, right below where the silk says U2
4. see? now try working with that x-ray vision for a while and see how good you feel
5. but you need both. I looked at decoupling from the MIC's perspective in 3. looking from the BQ, VSYS looks nicely decoupled on top but the ground return could be more direct. you could take REGN around the left side of U1, for example, and have a shorter, wider ground between U1 and C1. after all, you don't need a rock solid power ground for I2C. I'd also think about routing single traces between the filled zones on top to keep the ground coarser on the bottom, eg route VSYS and maybe STAT on top from R1 along VOUT near C6, then down under C6 and dipping under SW (for VSYS) or up to the LED in the corner. now U1's ground is nicely connected with the other heavy power paths in the rest of the circuit. those are the sorts of things it's helpful to look for

[Anonymous No.1791650]

>>1791645
you could, but get them charged well before they hit their voltage cliff so that you don't drive the more used one too low to safely charge

[Anonymous No.1791654]

>>1791403
What program is this?
Asking because I'd like to model my enclosures in Fusion360 and import my gerber or something so that I can see how it all fits.

also roll

[Anonymous No.1791655]

>>1791654
Nice, always wanted to make a game of life. Maybe I'll make one but simulating spread of infectious disease instead, to celebrate the festivities.

[Anonymous No.1791657]

>>1791654
Pretty sure it's just KiCAD, it has a 3D view built-in. Ray-tracing too, though it takes ages to render. It really is great software.

[Anonymous No.1791658]

>>1791657
Oh, nice. I downloaded KiCAD but didn't play too much with it, it seems kind of complicated - I use EasyEDA right now which is very intuitive, but I've been meaning to move to KiCAD because its FOSS.
Do you know if maybe you can export the 3D model in some kind of CAD format?

[Anonymous No.1791659]

>>1791655
Maybe I can use RGB LEDs, and light up green for infected, blue for recovered, red for died.
Anyone wanna get in on this?

[Anonymous No.1791661]

>>1791658
Probably? It's a relatively open program and all the 3D models are made in FreeCAD or something in the first place. There's also a bunch of user-made plugins or so I'm told, one of which is likely to do so if it isn't a native feature.

[Anonymous No.1791681]

>>1791646
Thanks for helping me with this.
2: I missed that. However I'm fairly sure it does have a connection I'll have a look with a thermal cam just in case its just barely connected.
3: Thats an idea I'll see what I have left over in MLCCs
5: Cant realy roll a new board in the short term but I'll try to apply this when I get around to it.

[Anonymous No.1791690]

>>1790957
schottky's are only fun for signal rectification, not for power. lol
>>1790966
those are usually 2 or 3 stacked schottky's
> selenium rectifiers also use schottky barriers

[Anonymous No.1791693]

>>1791403
is this a guitar pedal?, the text on the bottom suggests instruments and you don't see antiparallel diodes very often outside of guitar/synth electronics. what is the schematic you are designing this for?
and please, ceramic caps in audio gear... use foil caps

[Anonymous No.1791790]

>>1791690
Uh they are used extensively in low voltage power converters. High efficiency mains/low voltage DC converters wouldn't be able to be made without schottkys.

[Anonymous No.1791815]

>>1791658
It sure can. STEP imports nicely into Fusion with 3d parts and colours.

[Anonymous No.1791820]

>>1790966
SiC schottkys exist now with much higher reverse voltage ratings, still a bit too expensive for a lot of applications though, especially for mains frequency where the switching losses don't matter.

[Anonymous No.1791921]

My ps4 keep giving me the error CE-34335-8, i have buyed a new hd but nothing changed.

I oppened it and find a short in the circuit that gives power to the hd in these two parallels capacitors.

After i have taken off the fuse and the first capacitor closer to the fuse, the short is gone, it was this first capacitor. i just need to know the value to replace it and also i would like to see the data sheet for this IC AKTBB.

[Anonymous No.1791924]

>>1791921
Pretty sure you'll be able to find a circuit diagram for a PS4 online, plenty of people have done rework on playstations before.

[Anonymous No.1791929]

>>1791924
there is no schematic, sony haven't published it

[Anonymous No.1791946]

>>1791929
No user gathered schematic? Can you desolder the other cap and measure it? You could also just measure its dimensions, the voltage it's at, and check on digikey for a matching one. That should narrow it down pretty well.

[Anonymous No.1791947]

>>1791921
you're sure it wasn't the fuse?
it looks like that is just a power supply bypass cap, exact value shouldn't be critical. just replace it with the largest value 25V* ceramic you care to afford in that package size, which looks like 1210 (inch) aka 3025 (metric) but measure the package to be sure
* 25V assumes a 12V power rail and the rule-of-thumb of derating working voltage by 50% or more. if the actual voltage is e.g. 5V, replace with a 10V or 16V cap

[Anonymous No.1791953]

>>1791946
thats a good idea, i just think about ask first because i don't like to mess with things too much since i dont have all the proper tools to do it at best.

>>1791947
i measure the cap after take it off and it was shorted, i think the fuse is ok. i'm only afraid the short has damaged the AKTBB regulator, i'll take a look in these measures

[Anonymous No.1791963]

>>1791953
switching converters usually come with decently robust self-protection. in current year there is still no complete, free compilation of SMD marking codes, but if you know the manufacturer some will provide a list of their own product for public download. a clear closeup of the SOT23-6 package can sometimes show a recognizable style by manufacturer and help identify for closer searching

[Anonymous No.1791974]

Can someone recommend me books that cover circuit analysis with diodes?.

[Anonymous No.1791981]

>>1791974
>circuit analysis with diodes
You mean like diode logic, or RF diode switching, or weird shit like ring mixers and other arbitrary circuits?

[Anonymous No.1792023]

If I have an old PC case that I want to re-use, how easy is it to swap out the front panel USB ports for USB 3.0?

[Anonymous No.1792059]

>>1792023
>PC
>>>/g/

[Anonymous No.1792138]

>>1792023
Not really a question for here. But open the thing up and see what sort of mounting those USB ports have in the first place. I'm guessing they'll be on a small circuit-board of some sort with a multi-pin connector in it leading to a USB hub IC on the motherboard. Or maybe the hub is on the extra boardlet. Either way, it will likely be pretty standardised so you should be able to buy a USB 3.0 drop-in replacement, with the same mounting-holes and everything.

/g/ has a pc building general though, so ask someone who's actually put a pc together over there.

[Anonymous No.1792215]

>>1791646
I figured I'd let you know. I just placed down a leftover 10uF cap right where you said in 3.
And now it just drops down by 100mV to 5V which is perfeclty fine for me right now. Thanks for the help. I definetly learned something from your posts that will help me in the future.

[Anonymous No.1792219]

>>1792215
excellent. for funsies, try inserting a cap from VOUT to GND nearer U2, between the horizontal row of five GND vias and the VOUT via. C10 should have gone here instead of after all that trace self-inductance
have you tried it at higher currents yet?

[Anonymous No.1792230]

>>1792219
This beeing my first SMD project I have no caps left. I'll see what I can salvage of some garbage boards I have laying around.
>have you tried it at higher currents yet?
I could try a 2.5 Ohm load for a couple of seconds.

[Anonymous No.1792287]

>>1792230
So I managed to salvage some 10uF caps. Not sure about the voltage rating on them but they come out of a similar application and are just a little smaler.
With just the cap at the U2 place it would drop down to 4.2V with the 2.5Ohm load.
With the one described in >>1792219
it now only drops 30mV which is great.
Thanks again.

[Anonymous No.1792308]

How to drive/trigger a thyristor with a logic IC output? Logic IC has its own 5 V supply. Thyristor & load supply is 24 VAC / 50 Hz to stay safe. The thyristor will only conduct during positive AC half-cycle. I'm building a pulse-skip circuit which will trigger the thyristor either on every half-wave or every 2nd, 4th, 8th, "n"th,... half-wave.
Never worked with AC circuits before. Pic related was the closest I could find, but it uses a DC supply for the thyristor + load.

[Anonymous No.1792352]

I haven't yet found a datasheet about this electro motor, all I know as of now is on the sticker on pic.
Can't really figure out how to connect it though, there's 2 wires connected to the housing for ground, 3 wires for live.
One live wire connects to 2 red ones, one to 1 white one, and one to 2 blue ones.
From that point they all fuse with the main coil, apart from a blue and red wire that connect to the + and - of a fairly big cap.

[Anonymous No.1792353]

>>1792352

[Anonymous No.1792387]

>>1790136
So I'm a senior about to graduate in EE, but even so, I still feel like electronics projects kind of lose their luster what with the instantly available technology to be found in the modern world. Maybe it's just me. Or maybe there are things that can be done in independent electronics that just can't be bought that I'm not thinking of?

[Anonymous No.1792431]

Someone gimme a good infosource on op-amps, I have a degree in EE and I still don't really feel like I get them, I basically passed by acing embedded systems and scraping by everywhere else

[Anonymous No.1792445]

>>1792023
The ports on the front are just extensions of the ports on the board. If your new mobo has USB 3.0 the panel ports youplug into the connectors on the mobo will be 3.0. Unless it's some whacked-out case for crazy people none of the actual interface is going to be on the panel itself.

[Anonymous No.1792478]

rolling

[Anonymous No.1792497]

>>1792431
just google schematics lol
adding, inverting/non-inverting, log/antilog amps, all just a google away.
As far as solving them, basically just set V(+)=V(-) and use KCL on the feedback nodes

[Anonymous No.1792510]

>>1792353
The green and yellow wires are ground

[Anonymous No.1792512]

I found out this guy on Hackaday and tought on sharing

https://youtu.be/Y5kkgO5MPIA

[Anonymous No.1792542]

I am looking for an adapter from jack to rg58.

I found this on ebay: https://www.ebay.com/i/123862273020?chn=ps&norover=1&mkevt=1&mkrid=724-128315-5854-1&mkcid=2&itemid=123862273020&targetid=885342341400&device=m&mktype=pla&googleloc=1008139&poi=&campaignid=9566708095&mkgroupid=99670951658&rlsatarget=pla-885342341400&abcId=1145978&merchantid=116461045&gclid=CjwKCAjw4KD0BRBUEiwA7MFNTTFDUm9kvfRGC6FW3q3GC0xxBFSFDLpFoZY6aF_Ys1CIFDSa-36TDRoCWaoQAvD_BwE


But I don't wanna spend 4€+6€ of shipping.

I can't find it on aliexpress, can you help me find it?

[Anonymous No.1792553]

>>1792542
>rg58
just buy both separately and solder them together

[Anonymous No.1792565]

>>1792353
Test the resistance between those 3 red wires, and also to the terminals on that capacitor.

[Anonymous No.1792574]

>>1792287
solid

>>1792308
the trigger for a triac is usually referenced to a particular main terminal. for true ac operation you'll want a phototriac-based optoisolator like MOC303x/304x to replace the FET/resistors

>>1792387
custom interfaces to the material world, which is heavily flavored with applied physics. literally everything else can be bought

>>1792431
what's so hard about Vo = (V+ - V-) * Aol
I mean, that's it, aside from weird implementation details and out-of-spec operation: they basically try to make V+ = V-, solving whatever equation you throw in the output feedback loop
Nuts and Volts did a couple of series on them in the 2000s. one for regular opamps and one for OTAs. they might have even done one for Norton opamps. PDFs are available for download

>>1792445
USB 3.0 is different physically and electrically. the speed increase requires even better length and impedance matching in the pigtail from panel to motherboard

[Anonymous No.1792597]

Are there good simulation programs?
I try to learn topics, which we had in college but i think it's easier, if you "build" it.

I tried the falstada and EasyEDA, both kinda sucks
,even the basics.
10V and 10A and the LED still works.
The Multimeter shows at the end 9,93V (Which is right but the LED is burned = 0V). If possible to show brightness as well.

Does such a software exist?

[Anonymous No.1792612]

>>1791981
It's circuit analysis but with diodes, it seems to be very basics so i doubt it's any of these. Basically mesh/node circuit analysis but with diodes. I'm failing to get the procedure so i want to review it, but i'm having some trouble finding books.

[Anonymous No.1792615]

>>1792597
ltspice

[Anonymous No.1792632]

>>1792597
Yeah I'd go with LTspice. It won't show you things like how brightly an LED is turned on, but if you measure that the current through it is over it's rated current, it's probably dead. For your information, a common 5mm LED is good to about 20mA, and has a forward voltage somewhere between 2V and 4V (3V for blue or white, 2V for red, 2.5V for green, etc.), though IR LEDs are closer to 1V.

[Anonymous No.1792652]

>>1792597
simulator ≠ virtual workbench
no non-toy sim will protect you from ignorance and few sims at any scale bother much with thermal factors. you need to be smart enough not to feed 10A into small hobbyist LEDs. how's the sim supposed to know you're not dealing with a gigantic LED die on a water block, that can handle 10A?
LTspice is hipster shit with a bunch of $5 precision opamps you will never use, and no LM358s afaict. also the UI is kinda lost in time
Micro-Cap has a much better library of thousands of parts you are more likely to have and use. I haven't tried the smoke-testing (absolute maximum checking) functionality yet, but it's there and the developers are proud enough of it to make it a tip-of-the-day

[Anonymous No.1792654]

>>1792652
>also the UI is kinda lost in time
What UI?

[Anonymous No.1792755]

>>1792652
>micro crap
>not being developed anymore
Great suggestion my dude. Also you can literally google the manufacturer provider model and use it your simulation or use the generic opamp model and change the parameters as you need. LTspice might look like shit but it is very good

[Anonymous No.1792757]

>>1792597
orCAD Pspice. Pirate it if you have to.

[Anonymous No.1792768]

>>1792654
schematic capture, for example, is a bit clunky

>>1792755
>might look like shit
that despite that it's "being developed anymore", AND it's a SPICE underneath just like all the others, shipped with a less generally useful set of models, AND if you're not using LTC/ADI parts it's every bit as supported as Micro-Cap ie good luck sucka
so what, exactly, is LTspice's value proposition, other than nebulous and characteristically immaterial claims of
>being developed anymore
2/8 made me reply

[Anonymous No.1792773]

>>1792768
>Micro-Cap
What's the UI like? I'm already decently gud at LT and don't wanna waste time learning another set of snowflake hotkeys, but are they standard (like ctrl c, ctrl z) and/or easy to use, or is it all point-and-click menu-diving?

[Anonymous No.1792775]

>>1792768
>schematic capture, for example, is a bit clunky
Nah the joke was that there's practically no UI at all

[Anonymous No.1792783]

>>1792768
>chematic capture, for example, is a bit clunky
For some reason Analog can make super complex ICs but can't think of practical hotkeys. If you change
>rotate
>mirror
>delete
>wire
>move
To actual normal hotkeys. (Mine are r,e,del,w,m) the program is actually fast and intuitive to use. And there is no lack of help resources
> other than nebulous and characteristically immaterial claims of
From their website
News:

Effective 7/4/2019, Spectrum Software is closed. Micro-Cap is now free.

Technical support will be available for at least 90 days via email at Support.

You can download the latest versions of Micro-Cap here: Download
You can choose either the executable program or the entire installation CD for MC10, MC11, and MC12. If you have an earlier version, download and use MC12. These new versions do not require the security key, so they make Micro-Cap free to the entire engineering community.

Thank you for the honor and privilege of serving you for the last 39 years.

Spectrum Software

[Anonymous No.1792784]

>>1792783
And btw, I'm no shitting on micro cap. It seems like a good software (hell it was there for 40 years and released for free after that). Just pick your poison and git gud.

[Anonymous No.1792890]

DRC is pointing out that q1 and q2 have no connections but clearly they do.

The footpring I'm using is TO-92L_Inline, what gives?

[Anonymous No.1792893]

>>1792890
zoom out so we can see the rest of that net

[Anonymous No.1792915]

what is the maximum voltage i can run a pc fan on long term without it dying too fast?
normal fan voltage is 12V but i need it just doesn't suck enough, i need MORE POWER

[Anonymous No.1792935]

>>1792915
Get another fan

[Anonymous No.1792983]

>>1792935
I can't i only have one slot for it, i could stack them on top of each other but i am unsure if that would make 2x suction or some weird air whirpool shit resulting in say only 1.1x suction

[Anonymous No.1792993]

>>1792612
Just assume the diode is either shorted or open, do nodal analysis, and check your assumptions to make sure they're still valid. If they aren't redo your analysis with revised assumptions. This applies to a lot more than just diode analysis though, it's the same procedure with transistors except you usually assume saturation.

[Anonymous No.1793009]

I made this sketch of an SCR control circuit, but I don't think it will work the way I intended (0, 12 %, 25 %, 50 % power control). I think it would need some kind of monostable circuit between the D flip-flop and the opto that would give short trigger pulses to the thyristor. But the circuit is already ridiculously complicated for such a simple function.

[Anonymous No.1793010]

>>1792983
The thing is PC fans aren't simple DC motors. They need a control circuit to sense their position and give the correct pulses. If that is really what you want I'd buy another of the same model and do tests. (I don't know what voltage the control circuit can handle). You could also try looking at the circuit (usually it is accessed by removing the sticker and fucking up the fan) and see their parts and stuff.

[Anonymous No.1793016]

>>1792993
What happens if you're operating your transistor in the linear region (ie. amplifier). You wouldn't model it at saturation or cutoff then I'd think. Not the guy you're responding to btw just curious.

[Anonymous No.1793017]

>>1793016
For bipolars you assume they are in the linear range, for FETs it's saturation. Whoever chose those names was a very unfortunate person.

[Anonymous No.1793019]

>>1793016
Are you talking about BJTs or FETs? The terminology is different for each. Most of the time you're using it as an amplifier so you assume you're operating in that region, and if you're not you need to change however you're biasing that transistor. I haven't really done any CMOS/digital stuff where you actually care about the triode region.

>>1793017
Yeah, pretty confusing unless the context is explicit.

[Anonymous No.1793059]

>>1793017
>>1793019
I'm probably assuming bipolars as they are much more common in amplifiers than FETs. Although JFET differential pair front ends do show up every now and then so I guess it could be either.

[Anonymous No.1793063]

>>1793059
It's not the application that changes, it's the names. Saturation in a bipolar means a change in Vbe, changes little in Ic. Saturation in a FET means the same thing as Active region means for a BJT. (It's a really poor choice of name).

FETs have some really weird names for their regions and they really are not good. (I really wish I knew the reason behind them). Textbooks say the linear region behaves like a resistor (in fets) and it indeed does, but a very small one for most device

FET linear region => saturation in a bjt
FET saturation region => linear region in a bjt
FET cut off is the same.

[Anonymous No.1793067]

>>1793063
See pic related for some an explanation for the FET region names.

[Anonymous No.1793081]

I have a very basic question hope here is ok

Trying to repair headphones and I cant get the multi-meter to give a reading?

It doesn't have a buzzer just a diode mode.

Do I test when they are connected to the phone?

[Anonymous No.1793082]

>>1793081
What are you looking for? Shorts? Don't test it connected to the phone. If it doesn't have a continuity mode/buzzer you'll just have to put it in Ohms and see where it's relatively low.

[Anonymous No.1793086]

>>1793082

I broke the jack to my headphones and bought a replacement jack. I'm trying to figure which wires to solder where. My headphones have five wires. I presume one is mic , two left right and two ground. I'm trying to find out which of the four wires are ground

[Anonymous No.1793096]

>>1793086
Is it a 4 pole TRRS connector? If so yeah, just test for continuity in ohms mode using the pin diagram for a TRRS connector and connect the right wires. Weird that there's five wires though. Is the original jack still connected so that you can probe which wire is which or did it break off completely? If it's completely broken off you might have to put the wires into a breadboard or something with the phone connected and output audio to figure out which wires are which. Not sure how you might go about determining which is the mic though.

[Anonymous No.1793105]

>>1793096

>TRRS

yeah its one of those.

i'm getting no movement from the multimeter tho so im gonna have to start trying them by touching them off the exposed wires one by one with the earphones in . :sigh:

[Anonymous No.1793116]

>>1792773
looks a bit more modern. cut/paste/undo are pretty standard everywhere, and hotkeys are fully editable/assignable. component placement is a bit weird, requires a hold-left-click-right to change the shape/orientation while placing a component
lots of help on formats for SPICE directives and parameters. filter design workbenches. decent collection of examples. 45000+ common components (including macros for shit like 3-phase motors). and more. it was pretty much *the* working designer's tool of choice while it was under active development

>>1792890
where are R10 and C5?
is there a complaint in the Problems/Markers tab about them or their net?

>>1792915
you're gonna need a bigger boat

[Anonymous No.1793134]

>>1793096
>Weird that there's five wires though
It's actually pretty common in TRRS headphones.

>>1793105
Be sure you melt or scrape off any enamel insulation, you should read ~32Ω from left or right to ground. Dipping in acetone could work too. Pushing the pause-play button will cause the resistance from the control/mic line to ground to drop drastically. If there is no button you'll need to measure its resistance, I think you'll get a relatively high but not unreadable value across the microphone's JFET.

[Anonymous No.1793135]

what does pulse-width modulation look like in the frequency domain
If I'm trying to construct a square wave with a 25% duty cycle via additive synthesis, what would I do to the harmonics to halve the duty cycle of a square wave?
How the fuck does that work out if the frequency domain is independent of the time domain

[Anonymous No.1793137]

>>1793135
Make such a square wave in python and fft it is my best suggestion
Matlab would work too
I suspect it's the exact same frequency components at the same amplitudes but with different phase shifts, but that's a random guess
>if the frequency domain is independent of the time domain
they're not tho

[Anonymous No.1793143]

>>1793134
>>1793096

So I just i guessed mic/control was blue, cut that off, and started connecting wires until i got sound. Made a solder and it works (!)

[Anonymous No.1793148]

>>1793009
get U101A's input off the ground a little bit. you can't depend on any individual copy of the comparator having an offset voltage that leans in the direction you want (can be ±9mV over temperature and voltage). so give it ~15-50mV on the - terminal
you need logic gates if you want those fixed ratios. try a diode-AND connection as in pic, which is easily adaptable to a rotary 3P4T switch. if you want an OFF position, disconnect the topmost pullup

>>1793135
for a 50% square wave it is f(x) = sum(sin(n*x)/n) over all odd positive n
for any non-50% square wave there will be even-order harmonics

[Anonymous No.1793151]

>>1793137
I gave it a shot, it looks like it does have the same frequency components, but also has triplets of even-order harmonics surrounding the odd harmonics.
Very neat. Unfortunately, my synthesizer does not have the resolution for me to accurately plot such harmonics, so I'll have to give something else a shot.
>they're not tho
yeah I'm just retarded

>>1793148
awesome, that simplifies it nicely. Thanks!

[Anonymous No.1793157]

>>1793143
Better be using plenty of flux there buddy

>>1793148
>even order harmonics
of course, that makes sense

>>1793151
Trying to use a synthesiser IC for this is likely the long way to skin this cat. Anything stopping you from using a digital output on your micro, assuming you're using a micro?

[Anonymous No.1793158]

>>1793135
fucking mess is what it is. From what I read, it involves self-mixing
Might also have something to do with the sin(x)/x function

[Anonymous No.1793161]

>>1793157
No, I'm literally trying to make a PWM'd square wave for musical purposes in my DAW. I could do it with no problem using an stm32 if I needed an actual off-duty-cycle square wave, but this is for my own music

[Anonymous No.1793162]

>>1793157
>plenty of flux

I mean...I used a little before reigning down lead on that poor connector

[Anonymous No.1793172]

So I bought these beef ass inductors for high power boost converters but I have a slight problem. I want to prototype a circuit and they won't fit into my breadboard... not any protoboards I have in hand. Lead too thicc. What can I do?

[Anonymous No.1793173]

>>1793162
You don't want a dry joint on there is my point. It should be glossy and well-filleted and visibly soaked into the wire, not a dull-grey ball. That thin headphone wire is notoriously difficult to get good solder connections to.

[Anonymous No.1793180]

>>1793151
sure it does, go to options/other options and set the step size lower

>>1793172
don't use solderless breadboard for high power jobs like this, the inductance and capacitance combined with all that distance will destabilize it. the boards also hate high power
use copper-clad board instead
or use some dotboard, bend the leads of the inductor into gull wings and surface-mount it

[Anonymous No.1793186]

>>1793180
The inductor is way too big to surface mount like that. I won't be stable upright and it's weight will crack the solder joints. Fortunately I think I found a solution that will enable me to use breadboard, I just have to run some wires off to the connector and problem solved.

[Anonymous No.1793191]

>>1793172
>breadboard high-power boost converter
I think it not fitting is a good thing.

[Anonymous No.1793202]

>>1793191
I'm only using it for a 3-stage 12 to 200V 40W converter of which the first two stages will be boost converters and the final stage will be full bridge converter. 1st stage 12V to 48V, second stage 48V to 96V, final stage 96V to 200V. I only need like 3A of input current assuming I'm pulling the max 200mA load at 200V. And my switching frequency is only 200kHz. All that shouldn't be a problem for a breadboard. Breadboards suffer at like 20MHz+ and I think it can handle 3A of current a 200V between the rows. There's enough isolation. I think breadboards get undeservedly shit on here. People are fucking paranoid about them for no reason. Anyway the final design won't be on breadboard so relax. This is just for prototyping. I will layout a proper PCB for this eventually and have it manufactured when this whole corona thing blows.

[Anonymous No.1793208]

>>1793202
>3A
I wouldn't put 3A through a breadboard, not even 1.5A. The moment that plastic starts to soften from heat, you loose all spring-force holding your parts in place, potentially causing higher resistance in the connection and a proper meltdown.
I wouldn't worry about isolation though, I've got a 500V booster on a breadboard right next to me.

Pump 1-2A down a rail and measure the voltage drop across it for an actually useful metric though.

[Anonymous No.1793243]

>>1793208
I'll try that but if that's the case then this is really annoying because now I need perfboard with larger than normal holes to prototype with. I don't have boards with the right diameter holes on hand and I'm probably going to have a hell of a time getting them with everything shut down. Plus listings seldom tell you hole diameter.

[Anonymous No.1793285]

>>1793161
>not having a basic subtractive analog synth plugin with PWM
c'mon man

>>1793186
>too big to surface mount like that
then give it a base plate of some sort like the big bois do. hot snot it to a piece of popsicle stick or a bit of hard foam and have the feet stick out onto pads

[Anonymous No.1793288]

Opinions on the miniware mdp-xp?
Shits expensive for what it is but its breddy cute.

[Anonymous No.1793305]

Any recommendations on a reasonably priced flux that will work for desoldering and replacing failed smd components? Things like SOIC ROM chips and maybe plcc chips. I use leaded solder.

[Anonymous No.1793311]

>>1793208
>The moment that plastic starts to soften from heat, you loose all spring-force holding your parts in place

Have you never actually seen how solderless breadboard contacts work? It's a single strip of cut and formed copper (or more likely steel, in the shitty Chinese ones) just placed into a slot under the holes. They're totally self-supported. The plastic only keeps the pin centered.

I mean, it's not exactly a high-current bus, but they aren't signal-level currents only, either.

[Anonymous No.1793313]

>>1793305
I have a Kester flux pen that works really well, was like 10 bucks I think. I've used the bottled flux with the needle tip and I find I either use too much or get it everywhere, but some people tend not to like flux pens. Maybe for large components/many pins being able to squirt it on is preferable, but everything I do has been either a handful of header pins or a few, relatively small, components at a time.

[Anonymous No.1793314]

>>1793311
>They're totally self-supported
Oh yeah, my mistake. Here was I having flashbacks from overheating a 3.5mm audio jack.

[Anonymous No.1793315]

>>1793305
the ali shit is mostly vaseline
genuine Amtech NC-559-V2 isn't ridiculously expensive

[Anonymous No.1793322]

>>1793315
Thanks for the recommendation, will try it out.

[Anonymous No.1793365]

>>1793135
It weird to talk about time in the frequency domain but PWM looks like a weird sync function that changes a bit as time moves on.

[Anonymous No.1793437]

>>1790136
>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.

Can OP be more of a faggot?

[Anonymous No.1793447]

>>1793437
sounds reasonable to me

[Anonymous No.1793496]

if i have power drill that is running at say 10000rpm
and i lower it to 5000rpm by reducing the voltage in half (say form 100V to 50V), does that mean the torque will be half as well?

what if i reduce it to 5000rpm by using full voltage but 50% duty cycle pwm (typical square wave) ? will the torque be halved then?

[Anonymous No.1793532]

>>1793496
>reduce speed and voltage
Probably the torque will go down.
>reduce speed and keep the same voltage (maybe with gears)
The torque would go up
>reduce with PWM
Is the same thing as the first. Using PWM is just a way of changing the average voltage value.

[Anonymous No.1793551]

which retarded chink decided that giving all of their cheap encoders a shaft diameter of 6mm was a good idea
who uses that shit

[Anonymous No.1793583]

Is there any advantage to connect the LEDs on the emitter side of Q1 instead of the collector side?

[Anonymous No.1793585]

>>1793437
so where do I get started?

[Anonymous No.1793586]

>>1793585
>>1793447

[Anonymous No.1793587]

>>1793585
have you tried the books in the OP? Maybe... idk, the one that's called literally "getting started with electronics" might be a good starting point if you want to get started with electronics?

[Anonymous No.1793593]

>>1793583
Hold on, why is there a resistor for each LED?
Can't R4 and R5 be combined, as well as R7 and R8?

[Anonymous No.1793599]

>>1793593
Maybe they need some non-standard value resistance and need to combine two common value resistors to get closer or something.

[Anonymous No.1793622]

>>1793593
>>1793599
Source for the schematic is "Direction indicator for bike":
http://www.incbtech.com/index.php/circuit-bench/63-light-and-sound-effects/1451-direction-indicator-for-bike-cb931e

[Anonymous No.1793640]

how does the speed regulation works on this thing?
Do you think it's just a resistor? I would like to hack it and make it run about 60% slower since i want it to be quiet and run for several hours

[Anonymous No.1793641]

>>1793148
Thanks for your tip with the comparator. But I think my design is screwed right from the start. Because the D flip-flop frequency divider can only deliver 50 % duty cycle, exactly 50 % of the incoming half-waves will trigger the thyristor.

[Anonymous No.1793642]

>>1793640
won't it also become shit at vacuuming?

[Anonymous No.1793643]

>>1793599
>>1793622

presumably, it uses two 1 watt resistors which are cooler/cheaper/available rather than a single 2W.

>>1793583

putting the LEDs on the emitter is amateurish, but there's only a minor loss of efficiency.

>>1793532
>>reduce with PWM
>Is the same thing as the first. Using PWM is just a way of changing the average voltage value.

not true. PWM retains most of the torque at reduced speed.
to visualize the diff, think of one box being slowly dragged across the floor, while another is being shoved hard, but intermittently, so that their speeds are the same. if you were to stand in the path of each box, the second one would hit you harder.

[Anonymous No.1793648]

>>1793642
yes, but i only need it to vacuum small wood chippings so the suction power can be super tiny and there is no reason to run it at even half power which is loud and wastes energy

[Anonymous No.1793653]

>>1793643
PWM varies the average voltage (and hence power) in a motor. To keep constant torque with variable duty cycle a variable pulse voltage would be required. Rotor inertia plays no role in steady state

[Anonymous No.1793658]

>>1793641
Use a phase-locked-loop to mirror the frequency to a sinusoid, then chuck a comparator on that waveform set with the correct reference voltage to give a 20% DC. Assuming the output amplitude of the VCO is constant across multiple frequencies, that is.
Be out of phase though.

The best way would be to chuck an MCU in there that measures the frequency and outputs PWM.

[Anonymous No.1793662]

>>1793640
Phase angle control. You want a TRIAC, or one of these (basically a TRIAC in a box):
https://www.harborfreight.com/router-speed-control-43060.html

[Anonymous No.1793670]

>>1793662
thats pretty expensive, do you think a LED dimmer would work? i have one for mains that uses triacs and is leading edge, it is rated for 5A so current should not be a problem

[Anonymous No.1793676]

>>1793313
the trouble with the liquid fluxes is that they don't hold components in place with much tack and they don't shield the joint from oxygen (which is one useful service vaseline provides as an otherwise worthless flux)

>>1793622
the base isn't a control signal alone, it works in conjunction with the emitter, which is therefore also an input terminal. therefore any loads placed on the emitter will perturb the control signal you apply to the base and let less current through, which means your tranny is no longer a saturated switch, but a current amplifier
if you install a pnp equivalent with c and e swapped in place of Q1, you will lose less power in the tranny which leaves more power for your LEDs, which is what you want in a bike flasher

>>1793641
of course, you use the DFFs and their diode/switch arrangements to also hold the output off for (2^n)-1 out of 2^n cycles
the circuit I posted works fine in my sim. set it up in your own sim and try it for yourself

[Anonymous No.1793699]

https://www.radiolocman.com/shem/schematics.html?di=161283
Was looking about and I found this, which I think switches the rectified mains waveform off with a TL431 once it gets above a certain voltage, and buffers it with a capacitor. Which is similar to what an anon here was wondering about maybe a week ago.

I was actually looking if I could find a way to use a TL431 as a schmitt trigger comparator to make a self-oscillating mains buck converter with.

[Anonymous No.1793702]

Sorry if this is stupid, but I need you guys' help. After months of having to fight with the cable, my mobile phone charger finally stopped working, so I tried to cut most of the middle section of the cable, then I resoldered it, but it isn't working, any ideas what's wrong?
There were many very small copper cables inside also, I had to give them a little twist so they became nice and tidy.

[Anonymous No.1793704]

>>1793702
Oops, forgot pic.

[Anonymous No.1793715]

>>1793704
Uhhh actually it is now working, it seems the cable is still fucky. Sorry for the inconvenience.

[Anonymous No.1793720]

>>1793699
obviously not, you can't apply positive feedback from outside

[Anonymous No.1793724]

>>1793699
>this, which I think
inrush protector. used when the power supply input is especially inductive e.g. long wires. for an example of the failure mode this circuit prevents, see https://www.analog.com/media/en/technical-documentation/application-notes/an88f.pdf

[Anonymous No.1793727]

>>1793670
>$25
>expensive
Seriously? Well if that's too much for you you can find no name brand clones of that router speed control thing for closer to $10 on ebay or amazon.

>do you think a LED dimmer would work?
No I don't. LEDs can't be dimmed with phase angle control. I think they typically use PWM controllers, I don't know that your vacuum will like being pulsed like that. Probably not. You may burn out the motor coil.

[Anonymous No.1793734]

>>1793727
>LEDs can't be dimmed with phase angle control
4/8 made me do the research

[Anonymous No.1793736]

>>1793734
>high system liability

[Anonymous No.1793761]

>>1793720
https://www.radiolocman.com/shem/schematics.html?di=161395

[Anonymous No.1793768]

>>1793551
i'll show you a 6mm shaft diameter, faggot

[Anonymous No.1793772]

>>1793551
Isn't that pretty standard for metric rotary encoders and potentiometers?

[Anonymous No.1793780]

>>1793761
a Schmitt trigger is a specific two-transistor circuit topology, not just a generic word for "comparator with hysteresis". the answer to your question is still obviously no, you can't make a Schmitt trigger with TL431 because you can't add positive feedback from outside the package and there is none inside (the shunt transistor is an inverter in voltage terms, therefore the REF input is actually negative feedback)
buuuut read TI app report SLVA987 titled "Using the TL431 as a Voltage Comparator", maybe you can use two or more to get the action you like

>>1793772
inchfags need that extra 0.25mm to get off

[Anonymous No.1793791]

>>1793780
>a Schmitt trigger is a specific two-transistor circuit topology, not just a generic word for "comparator with hysteresis"
Well wikipedia says otherwise:
>From Wikipedia, the free encyclopedia
>In electronics, a Schmitt trigger is a comparator circuit with hysteresis implemented by applying positive feedback to the noninverting input of a comparator or differential amplifier
Regardless of what's actually correct, "schmitt trigger" referring to such a comparator configuration is what I was taught and seems to be rather commonly used.

As for whether pic related actually works as a schmitt trigger, I'll have to build the circuit on one of those tiny breadboards I've got somewhere around here. It looks like it will work, but whether or not it actually latches is something I've no clue about. I'd ditch the LED and probably R4 and R6 too, and shove another base-emitter junction somewhere to measure current and discriminate between the two states.
I'll look into that appnote thanks.

[Anonymous No.1793796]

>>1790136
is there anything beside proteus that I can use to sim PIC circuits?

[Anonymous No.1793801]

>>1793791
alright, I'll concede that definition
>whether or not it actually latches is something I've no clue about
that tranny is definitely offering (overall) positive feedback, so maybe it does. the next question would be one of speed

[Anonymous No.1793805]

>>1793801
>speed
Well people use these things as audio amplifiers so they're probably good to 40kHz at least, which could definitely be good enough for a switching converter. Whether that common-emitter transistor gets too deep into saturation is another matter, maybe adding a schottky will help.

[Anonymous No.1793855]

>>1793704
That's not how you do it, you fool.
1. Peel.
2. Twirl both ends. as many loops as possible. You can do it sideways (twist both) or straight (twist one on the other).
3. bathe with solder
4. electric tape
I suggest you test the cable after 3.

[Anonymous No.1793881]

Just checking before I do something irreversible
If I want to attach an external button/switch to this contact pad thing on a ps4 fightstick pcb, I would put the solder blobs in the red circles here and then just scrape the copper off the contacts down the middle to make sure they're separate?
There's no way I can accurately solder only onto one half of the tiny wavy pad thing, but scraping it off is good enough right?

[Anonymous No.1793887]

>>1793881
>There's no way I can accurately solder only onto one half of the tiny wavy pad thing
properly fluxed solder flows where it needs to go. what you described should be easy af, even with a big fat wedge iron.
If your soldering looks like crusty sticky turds you're doing it wrong

[Anonymous No.1793893]

>>1793887
I dunno, these things are pretty small, and while I do usually get nice shiny joints I'm certainly not "good" at soldering.
Also I only have flux core solder, which sounds like would just spread on its own?

Whatever, I'm game to try, but I'm expecting to have to scrape the traces in half at the end. Hopefully it works.

[Anonymous No.1793896]

>>1793855
>electric tape
>not heatshrink or self-fusing silicone tape

>>1793881
If you have enough flux and don't add too much solder (and don't shove the wire across the wavy bit) then you shouldn't need to scrape anything. Though I'd consider scraping the solder mask off nearby traces instead of messing up those button contacts.
Or better still, find a test-pad it's connected to. You should only have to solder one wire in such a janky way anyhow, I'd hope that the other contact is tied to ground or VDD. Then again, I'm not down on how keypad matrices are wired.

[Anonymous No.1793904]

>>1793893
Those things are gigantic, and the traces are clearly smaller. You risk lifting / damaging the traces by scraping rather than use the obvious exposed part? Anon, learn to solder.

[Anonymous No.1793907]

>>1793896
>>not heatshrink or self-fusing silicone tape
We're dealing with someone who can't splice together a joint. Got to assume they only have basic equipment.

[Anonymous No.1793908]

>>1793881
if you're going to strip out the middle metal, do that first so you can give even fewer fucks about accuracy and focus on stability when you attach the wires

[Anonymous No.1793914]

>>1793907
>basic equipment
I've been working without any electrical tape for a couple of years now, heat-shrink should really be enough of a substitute that nobody ever needs to use electrical tape. The adhesive on that stuff is awful, it slowly slips free and leaves behind sticky residue, though maybe the brand-name stuff is better. And for odd shapes the self-fusing stuff is really indispensable. A combination of both has never left me wanting vinyl electrical tape.

Though I recently bought a roll of electrical tape before the shutdown. Not for electronics mind you. My bicycle wheels had no rim tape to protect the tube from the nuts holding the spokes in tension, and my tubes were leaking air a bit faster than they should (having to pump them every week), so I thought a cheap roll of vinyl tape would do the job before I swap my tubes. Then my bike got stolen before I could do that. Saved a pair of tubes, that.

[Anonymous No.1793942]

>>1793914
>bike got stolen
Are you in Dublin?

[Anonymous No.1793956]

>>1793914
normies think that black electrical tape is suitable for general insulation on things that are touched and moved. normies are silly, it is true, but normies also think the supermarket = the universe
be sure your next bike bears a proud label "PROTECTED BY CORONAVIRUS / KEEP 2m CLEAR OF THIS BICYCLE"

[Anonymous No.1793959]

>>1793942
No, I'm the anon who got his bike stolen last year too though.
It's the fourth/fifth attempt to steal one of my bikes in the past 3 years, depending on whether "removing the wheel bolts on a bike that's got a U-lock through the frame" counts as an attempted theft.

I'll likely buy one of those motion-activated-alarms for my next bike, but I think a GPS tag of some sort would be good too. Alongside a proper U-lock, of course.

>>1793956
>PROTECTED BY CORONAVIRUS / KEEP 2m CLEAR OF THIS BICYCLE
Good idea, but I won't be able to buy a bike until the lockdown is over. Perhaps something like "warning: seat contains herpes" would be better.

[Anonymous No.1793960]

>>1793959
>Perhaps something like "warning: seat contains herpes" would be better.
People who steal bikes don't do it to use them themselves. They just sell them at fences, so they couldn't care less.

[Anonymous No.1793961]

>>1793960
ok how about putting a fucking bomb in the seatpost to destroy the person's colon if they ride it without inserting a key

[Anonymous No.1793962]

>>1793961
You'd run a risk of destroying your own colon.
And often enough, the ride stealing gangs don't ride the bikes they steal. They just throw them into a van.

[Anonymous No.1793965]

>>1793962
>They just throw them into a van
Someone's gotta make a meat payment, plus the resulting investigation makes it pretty obvious who stole it, not like the police are ever getting my bike back otherwise. It also decreases the market for stolen bikes. I'd be the unabomber of bike thieves, deliberately buying scrap bikes and cheap bike locks, installing bombs inside them, and locking them up in seedy neighbourhoods.

[Anonymous No.1793966]

>>1793965
Or you could hurt an innocent person.
Just don't.

[Anonymous No.1793970]

>>1793966
Yeah I know, I'd never even be able to buy bomb components without getting pre-emptively arrested. They're better at catching the premeditated sorts than they are spur of the moment crimes like bike thieves, because of course they are.

Anyhow, it would be far more effective to take the dozens of scrap bikes and shove GPS trackers in them instead, and make a map of stolen bike hotspots, keeping the information until it's sufficient to be incriminating to a large number of thieves.

I bet a government subsidy on those consumer GPS tracking tokens would actually save money in the long-run. Or maybe insurance companies should be the ones selling them at a loss to their customers.
I'd want tokens with passive energy harvesting abilities though, none of this "1 year life" bullshit.

[Anonymous No.1793986]

>>1793961
there was a video on /pol/ a while back of the significantly less lethal stun gun in a seat

[Anonymous No.1793994]

>>1793727
>o I don't. LEDs can't be dimmed with phase angle control.
lol what of course they can you tard
they sell those in any electronics store

[Anonymous No.1794008]

>>1793437
Start with a simple idea and learn everything you need on the way
Ofcourse knowing the basics of how passive and active components work is important

[Anonymous No.1794129]

I've been testing around with this coil gun simulation.
How do I calculate the coil's inductance so I have the most amount of current flowing into the coil in the shortest amount of time? As of now I have about 3A within 10ms.
What else can I do to improve these factors?
Also how do I deal with that massive inductive kick? A simple flyback diode on the darlington won't be enough I think.

[Anonymous No.1794134]

>>1794129
Use zero inductance.

[Anonymous No.1794135]

>>1794134
But that won't make any bullets go fast : (

[Anonymous No.1794138]

>>1794129
What software is this?
Also the point of an inductor is that it stores energy (slowly) in the form of a magnetic field when current passes through it, and then when current stops flowing through it, that magnetic field slowly collapses, giving you a smoother transition.

In the coil gun, the inductor is actually what holds the energy that, when you close a switch, is released to move a nail a tiny bit forward. So after the nail passes the center, you need to switch the voltage potential off.

GreatScott has a video on it.
https://www.youtube.com/watch?v=PMU9TQUDhow&feature=emb_title

[Anonymous No.1794170]

>>1794129
afaik all you'll see when you're firing is the coil's leakage inductance as a result of imperfect coupling with the projectile. that leakage will be significantly less than the nominal coil inductance.

you'd best review the physics first, but you might be able to estimate the leakage inductance as L*Au/Ac where L is the nominal inductance, Ac is the area inside the coil, and Au is the "unused" coil area wasted by the barrel wall. that's assuming a uniform field inside the coil which i'm pretty sure is true enough. also like i said review the physics first, the actual formula should be simple as above but there might be some exponents in there.

[Anonymous No.1794200]

hey /ohm/. Going to be getting a board made here soon.

1) Recommendations for decent quality, low cost, American board manufacturers that can do small run or one offs
2) Are PCB houses still open during the Coronapocalypse?

[Anonymous No.1794202]

>>1794129
You'll need to do calculations that a circuit-sim can't do, calculations involving the dynamics of the projectile and hence its interactions with the magnetic field. For maximum firepower, you want your magnetic field to be virtually unchanged at its maximum for as long as possible, but as soon as the projectile passes the coil's centre-point you want to collapse the field. If you ignore the LC constant and just forcibly collapse the magnetic field, you could likely not bother with almost all of the aforementioned calculations. I think dumping all that energy into a second capacitor will be quickest, but what voltage and charge you want it going up to will make a difference to the speed. You could also use a power resistor (or zener or MOV or whatever), probably in conjunction with a diode, provided it won't raise the temperature of your part too much, but again figuring out the ideal resistance for such a method will also require some testing.

[Anonymous No.1794203]

>>1794200
oshpark if your board is small

[Anonymous No.1794205]

>>1794203
Is under 3.5 square inches considered small?

[Anonymous No.1794208]

>>1794200
>decent quality, low cost, American
pick any two because you ain't gettin' all 3

>>1794205
they charge by area. 3.5 * 5 = $17.50 for three boards
ordering from coronastan and shipping via DHL might be cheaper and faster still

[Anonymous No.1794249]

>>1794208
Thanks m80. Would prefer to have it made in the US because I don't want bug people to profit off my design. Pretty sure they would sell the boards if it would turn them a profit.

[Anonymous No.1794251]

>>1794249
>actually wanting the anglojew to profit off your design
out-group preferences confirmed

[Anonymous No.1794255]

>>1794251
I want no one to profit from my work. I trust white people to not sell my shit without my permission.

[Anonymous No.1794268]

Are c1, c6 and c22 distributed corretly? I want to avoid intereference.
Do tiny chickpea capacitors have this problem too?

[Anonymous No.1794302]

>>1794202
Not helping that he's using the most useless dumbd down sim on the planet. Falstad is not suitable for simulating any circuitry, especially anything more complex than a few passive components and even then it's too limiting.

[Anonymous No.1794303]

>>1794255
I'm white, post your design files and I'll show you how much you can trust me ;)

[Anonymous No.1794306]

>>1793855
Yeah I know I should have used a heatshrink or electric tape but I don't have any and where I live we are quarantined because of the corona.
Also thanks for the twirl tip.

[Anonymous No.1794308]

>>1794306
You're welcome. I'm also in isolation fwiw.

[Anonymous No.1794310]

>>1794306
Oh btw, twirl vs notwirl:
If you twirl, solder ends up reinforcing the connection through gaps and outside, and preventing self untwirling.
If you don''t twirl, the solder will tend to actually separate the wires and make a poor connection.

[Anonymous No.1794367]

>>1794135
it's a sim. it's cheap and easy to put a diode across the inductor and plot it in a scope
>spoiler: the diode will safely conduct the 3.5A (max) of kickback and dissipate only a few watts for a few milliseconds
SS54 Schottky diodes, 5A, 40V, SMA package, 40 cents each on mouser. if you're into that THT shit, SB540, same spec, axial leaded, 39 cents each on Digi-Key

>>1794302
you can use an interactive sim when you want to explore, on a qualitative basis, that some particular arrangement of *electronic* ideal components will respond to signals in the right way
if you haven't thrown out your idea for infeasibility, you can then use a batch ("real") sim with real component specs (the ones you'll most likely be using) for a quantitative analysis and final component selection

>>1794303
whatcha doin' rabbi?

[Anonymous No.1794501]

What's the best 360 degree digital servo to get if i want to make a clock using an arduino?

[Anonymous No.1794511]

The fans noise on my laptop is driving me crazy, it's always too loud for no reason (e.g. will start spinning @4000 rpm already at 45-50°), and of course there's no way to finely control it because the BIOS has no such options (actually they can be unlocked but they have no effect).

I tried 3rd party software to control it to no avail, because the EC seems to have an automatic mode which overrides whatever values were set manually, in case the temperature is rising "too high".
I though about soldering a variable resistor (max 10 ohm) in series with the power cable of the fan, but I don't really think is the best approach to solve this problem, for several reasons.
What are my best alternatives? I thought about a PWM duty cycle halver with a couple of logic cates and a flip flop but honestly the IC implementing them aren't that miniaturizable, and the reducing factor also can't be reconfigured.
Another idea was to hook up a really tiny and self contained uC (e.g. Attiny25) that could intercept the current PWM dc (assuming the frequency is known), and outputs a signal with the same frequency and reduced dc, but again, I'm not sure this could be really usable.

What do you guys think?

[Anonymous No.1794578]

finally! my new hair drier is here

no longer do i have to solder smds once by one like a pleb having to battle them moving around and shit, now i can just smear solder paste on, put them on with some tweezers and blow on that shit, done

this model is very high end, you can even select temperature

[Anonymous No.1794584]

>>1794578
Never worked with SMD, just THT. Should I try to solder normally or is it such a pain that I should just don't bother until I have one of those hot air guns?

[Anonymous No.1794599]

>>1794578
>now i can just smear solder paste on
i did this for a while until i realized that paste expires and i didn't want to keep buying it. now what i do is to roughly tin the pads manually with an iron, drown the board in flux, put the parts on, and reflow. the flux isn't as sticky as paste though so if you can't turn your gun's airflow very low like i can then your 0402s will get blown around.

[Anonymous No.1794601]

>>1794599
how the fuck can solder expire, it's not milk
does flux expire? i have a bunch of siriges full of that stuff rossman uses except chink made and i haven't got around to using it yet

[Anonymous No.1794614]

>>1794584
soldering soics, sots, and 0603 passives is easy. soldering tssops is alright if you have flux and wick for removing bridges. it isn't impossible to solder qfns by hand if their thermal pad is large enough for a PTH that you can feed solder through from the reverse side.

>>1794601
i can't find it now but i've read a whitepaper that shows pictures of expired solder paste, where the solder balls don't reflow into a cohesive mass but just scatter all over your board. no clue what component of the paste is actually expiring. i've had some chink flux for years that still works fine.

[Anonymous No.1794651]

I did a surgery on hdmi

[Anonymous No.1794656]

>>1794601
evaporation of flux and oxidation of the solder particles, and also as the metals oxidize, the flux gets consumed

always keep it in an airtight container and in the fridge

[Anonymous No.1794689]

>>1794656
interesting, my solder wire has flux inside and it lasts forever, yet paste expires like that? probably some jewery going on to force you to buy more paste

[Anonymous No.1794696]

>>1794584
some drawfag should do a "The chad tht user vs the virgin smd"
The chad THT
>lives in developing nations
>buys solely on brick and mortar stores
>never touched a temperature controlled iron in his life
>doesn't use bread boards, only solders stuff on copper clad
>solder bridges collapse when he looks at their general direction
>solely lead based solder

>Virgin smd
>needs tweezers to solder
>can't use other types of solder, only expensive solder or just orders their boards to be made in china
>doesn't leave his house, buys only online and doesn't support local businesses
>needs to buy break out boards, even with tiny smd components his projects are huge
>can't use a breadboard even if he wanted to

[Anonymous No.1794702]

>>1794696
Based fellow THT chad.

[Anonymous No.1794705]

>>1794689
In wire solder the flux is contained within the metal solder, meaning that the flux is sealed air tight.
With paste the flux is exposed directly to the air, so air can dissolve into it. The little solder balls in paste also have fuckloads more surface area with which to oxidize than wire solder does.

[Anonymous No.1794711]

>>1794696
>the BGA turbo virgin
>needs a machine to solder for him
>gets his balls broken all the time
>can't even apply solder without the help of stencils
>needs at least 4 layers to route everything

[Anonymous No.1794713]

>>1794711
>needs X-FUCKING-RAYS to verify his solder joints
can't make this shit up

[Anonymous No.1794732]

Currently experimenting with this fading LED circuit

[Anonymous No.1794757]

>>1794732
Have you considered an op-amp/transistor VCCS + ramp generator to fade an LED instead? Generating a linear current ramp seems easier than whatever you've got going on here.

[Anonymous No.1794770]

>>1794511
>>>/g/

>>1794651
GOAT controlled impedance

>>1794696
virgin: content hobbyists with zero ambition beyond reliving the 1970s (looking at the ground)
chad: people who use advanced components effortlessly and don't mind investing in their capabilities (ouch!)

>>1794732
please put some thought into your resistor values. you don't need to sink 15mA in U102A, 1mA should be more than fine for a signal

[Anonymous No.1794777]

hi /diy/, i want to learn about electronics, what are some useful links to start with? I have basic high school knowledge of how things work already.

[Anonymous No.1794801]

>>1794770
Goat what?

[Anonymous No.1794814]

>>1794777
Read the OP

[Anonymous No.1794817]

>>1794801
https://www.eeweb.com/tools/twisted-pair>>1794777

[Anonymous No.1794818]

>>1794801#
https://www.eeweb.com/tools/twisted-pair

[Anonymous No.1794825]

So I'm trying to fix a keyboard that I screwed up by spilling a bunch of kombucha on it. A few of the keys don't work (cherry mx switches), and in order to open up the switches I actually have to desolder the LEDs at the very least. (Backlit keys.) I know how to solder and desolder stuff in good condition, but some of the joints are really corroded from the kombucha. (Spilled it ages ago and just now got to disassembling the keyboard.) What sort of flux should I use given that some of the joints show lots of corrosion and organic contamination, or does it not matter? Also I heard that this is an acceptable cheapo soldering station:
https://www.banggood.com/KSGER-MINI-V2_0-T12-Soldering-Station-with-XA-Grade-T12-K-Electric-Soldering-Irons-Tips-p-1407447.html?akmClientCountry=America&p=YO02213926337201603A&custlixnkid=234930&cur_warehouse=CN
Good enough for some light work? I've only ever soldered using lab hardware, not my own.

[Anonymous No.1794842]

>>1794770
I highly doubt the consumer technology board would be able to help the fan guy. /g/ is a husk of what it used to be and expecting anything at all other than ricing, smartphones, and programmer socks is illogical.

[Anonymous No.1794848]

>>1794842
/ohm/ needs a wall for all the consumer faggots to stay on the other side of

[Anonymous No.1794857]

>>1794825
>What sort of flux should I use given that some of the joints show lots of corrosion and organic contamination

flux is the wrong thing for that. if one thing doesnt work, move to the next..
- alcohol and a toothbrush
- rub with eraser
- rub with scotchpad
- rub with a rounded knife tip
- jumper the pads or traces if they're broken

[Anonymous No.1794863]

>>1794857
I just meant flux for when I actually get down to desoldering. I've already gone to town with electrical contact cleaner and a brass brush. Maybe the brass brush was excessive but the traces all look fine. Like I said, I need to desolder the joints to take out the switches and see if I can clean out whatever gunk or corrosion is causing the contacts not to complete the circuit. The vast majority of the keys work fine so I'm assuming the problem is inside the switches themselves and they just need some cleaning where the contacts meet.

[Anonymous No.1794867]

>>1794848
Oh fuck off, he's not asking a consumer question. His question is entirely valid for this thread.

[Anonymous No.1794868]

is it ok to make pcb connections like the red line or do I need to make them like the blue?

[Anonymous No.1794869]

>>1794825
>T12
go for the 936D clones and save your coronabux for more masculine brewed drinks
for keyboard repair you'll probably want a 1.6mm screwdriver tip. you'll be able to heat both leads of a 3mm THT LED at once with that
and probably some paste flux. RMA should be active enough for most repairs as long as you've given her a good washing with water and alcohol first. no-clean probably is not. when using activated fluxes, be sure to post-clean the board with alcohol and a soft brush (old toothbrushes are alright)

>>1794863
>The vast majority of the keys work fine
another possible cause: some matrix lines may have unwanted conduction to neighboring and/or perpendicular matrix lines, possibly internal to one of your switches

[Anonymous No.1794875]

>>1794868
red is fine.

[Anonymous No.1794894]

>>1794868
perfectly fine. the soldermask limits how far down the trace any extra solder goes, which will be about 0 fucks worth

[Anonymous No.1794903]

>>1794869
>RMA should be active enough for most repairs as long as you've given her a good washing with water and alcohol first.
Thanks, that's exactly the information I needed.
>another possible cause: some matrix lines may have unwanted conduction to neighboring and/or perpendicular matrix lines, possibly internal to one of your switches
Ouch, I hope not. Individual switches are stupid expensive, and it's not a very common switch type (clears).
>save your coronabux for more masculine brewed drinks
More of a vodka man, myself.

Here we are hunkering down for the worst chink plague in a hundred years, and I'm buying cheap chink shit to keep myself busy.

[Anonymous No.1794937]

>>1794903
>pic
STOP
you will not need 50ft of desoldering braid, and braid isn't even the best tool for this, much less if the holes on your board are as oversized as mine are. skip that and find a Soldapullt (brand name for Edsyn solder sucker, accept no substitutes) https://www.ebay.com/itm/EDSYN-US340-Static-Safe-Universal-Soldapullt-Desoldering-Suction-Tool/143358064044
>Individual switches are stupid expensive
a buck each isn't actually terrible for what you're getting. I've had a shitty gamer MKB sold with Kailh blue switches for a while, which I've been rekeying with MX blue as switches fail
>More of a vodka man, myself
that much is based
>worst chink plague
next time leave your infected cyclists from Fort Detrick at home

[Anonymous No.1794951]

>>1794937
I've used braids and desoldering guns (the ones with a motor) in the past and I prefer braids. I guess I could get both but if I do just fine with braids, is there really any point? I learned how to desolder before I learned how to solder and I like the simplicity of braids. It was also a good deal compared to 1/10 the length for 1/4 the price.

[Anonymous No.1794959]

>>1794951
50' will outlast the typical hobbyist. I'd suggest you get different widths of that stuff. I bought all 3mm last time I ordered braid, wish I'd have gotten some 2mm or even smaller for some of the SMT shit I do
I find the manual sucker a lot less hassle for getting through-holes and the component leads free and smooth, so that I need fewer hands when I grab pliers and pull the switch out of the metal frame from the top side, and so when I go to reinsert the new switch into the frame and board I don't have to heat the holes to get solder out of the way

[Anonymous No.1794978]

>>1794825
T12 certainly isn't bad, it's what I've got and it works a treat. Its advantages over the 936D clones is that its tip and thermocouple are one in the same, your temp reading is going to be more accurate so you'll get less thermal lag, and its digital readout with user-settable standby and sleep times and temperatures (and boost temperature) make it very convenient to use. The tips are also hot-swappable if you have a silicone mat to grab the hot tip with. But these T12 tips are significantly more expensive in case you want more than 2 or 3, and the whole thing is more expensive overall. If you do go for the T12, don't get the wide gray plastic handle, get the particularly thin handle (my one's blue with a black grip) instead, they have a much better method of fixing the tip in place.

Either way you'll want a stand for your station, and the T12 probably doesn't come with one. Copper wool is also very useful, far better than a wet sponge in my opinion. Desoldering braid and/or a solder sucker help.

>>1794903
>Here we are hunkering down for the worst chink plague in a hundred years, and I'm buying cheap chink shit to keep myself busy.
Not like anyone else is selling shit, chinkshit is all I can buy!

>>1794951
>>1794959
Any of you tried hollow desoldering needles? They look great for THTs.

[Anonymous No.1794990]

>>1794268
you need to add some mounting holes

[Anonymous No.1795000]

Can I use a smallish mains stepdown transformer as-is as a demagnetiser? Or is 50Hz too fast or slow? Do I need to make it open-core?

[Anonymous No.1795054]

>>1795000

> is 50Hz too fast or slow?
commercial units use line frequency, so you're good there

> Do I need to make it open-core?
of course, you want the magnetic field to leak out. transformers try to do the opposite for efficiency. so you have to hacksaw off the top of the core.

[Anonymous No.1795057]

>>1794818
Ok I got it, but what's the point of making it for 5cm cable? Anyway later I'll install a normal cable from fpv headset. Here is what this thing was made for.

[Anonymous No.1795066]

>>1795057
rpi4 running kali linux? l33t haXX0r
Why is your battery shield thing taking up more space than the actual batteries? Also you should use LiPo batteries for that kind of application IMO.

[Anonymous No.1795073]

>>1795066
>Why is your battery shield thing taking up more space than the actual batteries?
>>1794696
>>needs to buy break out boards, even with tiny smd components his projects are huge
TOP KEK

[Anonymous No.1795197]

What are the best ways to get into electronics with no equipment? I've already started reading books and doing practice problems. Are there any projects worth just reading and following along with no equipment?

[Anonymous No.1795204]

my stupid fucking brain won't remember the differences between the main transistor types. I've looked it up god knows how many times and after 24h i've forgotten everything.

[Anonymous No.1795213]

>>1795204
there are only 4 that you care about:
>NPN:PNP (BJTs)
>NMOS:PMOS (MOSFETs)
bjts are for analog. fets are for switching. n-types are for everything. p-types should only be used when you can't use an n-type or don't care that your transistor sucks.

[Anonymous No.1795229]

>>1795213
what about jfets and igbts
also, bjts depend on the gate current, the others gate voltage? welp, here we go for another round of reading stuff up...

[Anonymous No.1795232]

>>1795229
>JFETS
dead
>IGBTs
high voltage power conversion that you shouldn't be fucking with

[Anonymous No.1795247]

>>1795229
Just read about "what are IGBTs". Odds are you'll never have to use one. Don't waste too much effort of understanding them

[Anonymous No.1795284]

>>1795213
>not using MOSFETs for analog purposes
They're the ideal final stage of a linear audio amplifier, since they don't need high base currents for driving the BJTs. Just whack some negative feedback between output and input and you're golden. It's audio frequency so gate capacitance is also a non-issue.

>>1795232
>>JFETS
>dead
No they're not, they're used where high input impedance is paramount, like in JFET op-amps and radio receiving circuits. They're also in every electret microphone capsule under the sun.

[Anonymous No.1795289]

Can I route below a 0603 resistor like this or is it too close?

[Anonymous No.1795312]

>>1795289
0.2mm sounds fine, so long as it's logic-level and not 50V or something. Also ensure your solder mask will cover it sufficiently, might want to consider making the trace a little narrower through there if the solder mask might not cover it all.

[Anonymous No.1795314]

>>1795284
>high base currents for driving the BJTs
Just use Darlington/Sziklai pairs bro

[Anonymous No.1795399]

>>1795312
like

[Anonymous No.1795400]

>>1795284
In linear mode mosfets tend to overheat and then "pop" due to thermal runaway. Even if you have negative feedback on the entire device, there is positive feedback inside which means you get hot spots within the package that carry all the current.

[Anonymous No.1795402]

>>1795400
Now that's something I've never heard before, interesting. Do those variable loads use MOSFETs or BJTs as their limiting element I wonder? Or are they switching elements in a buck converter feeding a somewhat low resistance on a heat-sink?

[Anonymous No.1795406]

>>1795400
Does that apply to all mosfets?
I've heard of that issue in mosfets optimized for switch mode applications, but not mosfets in general.

[Anonymous No.1795476]

Where do I buy silicon electrical steel sheets? I want to get them laser-cut or waterjet-cut in order to try out custom transformers and motors and cool shit like that. Preferably already with a coating on the sheets ready for lamination, but if I have to I can do that myself with some sort of thin lacquer.

[Anonymous No.1795514]

>>1795213
>no jfets
spot the arduinobabby

[Anonymous No.1795516]

>>1795289
Just use via and route it on the other side or if it's full there, most fab houses can do up to 4 layer pcbs

[Anonymous No.1795547]

I want to measure the saturation of a transformer, maybe a motor too, but all the hall-sensors I see only go up to 0.1T or so (1000 gauss), which I'm pretty sure isn't high enough to see saturation. Are there any low-sensitivity magnetic field sensors out there? Checking octopart and mouser thoroughly doesn't yield anything over 1000 gauss.

[Anonymous No.1795559]

>>1795213
Thyristor and Triac are good to know, too.

[Anonymous No.1795614]

>>1795406
I'm not sure, but if you have a device in mind you can look in the datasheet for where the temperature lines cross. If the current is low enough it will never produce enough heat to cause a problem even with the positive feedback, so high power situations are where you really need to be careful.

[Anonymous No.1795638]

>>1795284
shut up retard, the guy we're replying to can't even remember what a bjt is. you think complicating things is going to help?

[Anonymous No.1795856]

Can someone explain what frequency-dependent negative resistors are and why you'd use them?

[Anonymous No.1795892]

>>1794757
>op-amp/transistor VCCS + ramp generator
Sounds like something linear... I'm more interested in PWM fading at the moment.

>>1794770
>1mA should be more than fine for a signal
Good point

I tried to extend the previous circuit to create a traffic light with smooth on/off transitions. At the moment only the on->off fading works and off->on transition is instant.

[Anonymous No.1795893]

>>1795892
Video of the gadget

[Anonymous No.1795946]

So I've been getting back into Altium after an extended hiatus with electronics in general (current job is all mechanical drafting and no electronics).
The irk I'm finding with this software is the line drawing capabilities. Is there a way to draw lines like you would in AutoCAD? I want to specify line lengths but the only way I can conceivably achieve that is by specifying start and end points in reference to the origin. I just want to be able to draw a line and specify the length to be 5mm or 12mils or whatever length I require the line to be. I can specify width just fine but specifying lengths or even slopes seems to be overly cumbersome.

[Anonymous No.1795985]

I'm back again with my starlight CCTV camera night vision goggles. For my first attempt, I tried a digital solution but even with a wired ethernet connection there was still significant latency (0.5-1s+) between what happens IRL and what I see on the screen. I was advised to keep it analog to minimize latency.
So now I've picked out a new CCTV module that has 60fps and outputs 720p or 1080p images over CVBS and I found a wearable display that is 1024 x 768 resolution. Since the resolution is not the same, will the image be distorted? Is there a way to make it so the image is cropped instead of stretch? And as usual, will this difference in resolution result in excess latency?

[Anonymous No.1795990]

>>1795559
What do you ever use a thyristor for though? A TRIAC is used often on AC waves, but thyristors latch on, so they’re only useful when you’re dealing with an unfiltered rectified sinusoid.

[Anonymous No.1796023]

>>1795990
>?
Both triacs and thyristors latch on. The triac is essentially two thyristors in anti parallel making it useful for AC.
Thyristors are less useful, but I've used big ones in coilguns to dump the energy of a capacitor into a coil. I've also seen them used in "crowbar" style overvoltage protection circuits, to short the output of a failing power supply and keep it shorted until the fuse blows.
I've even used a small one to charge a capacitor fully with one pulse.

[Anonymous No.1796110]

>>1795946
Do whatever this guy does:
https://youtu.be/_-YDuCqEwuw

>>1796023
>Both triacs and thyristors latch on
Yes I know, but because they're used in AC it isn't really a problem, you just get a maximum limit on your PWM frequency. But 99% of DC systems don't have 0-crossing often enough to warrant using an SCR
>coilgun
I'd have though a MOSFET or IGBT would be better, since I'm pretty sure it's common to want to cut the power off just as the projectile passes the centre-point of the coil. No clue how you dump that energy though. If you instead calculate it such that the coil has no magnetic field by the time this happens, an SCR is perfectly acceptable, but you're losing out on some acceleration if you do this.
>crowbar
That makes a lot of sense, but still somewhat niche.

Anyhow, my point is he was listing transistors for noobs to care about, those being BJTs and MOSFETs, deilberately ignoring IGBTs and SCRs and such because their uses are obscure enough that he doesn't need to know them immediately. A TRIAC is definitely something useful to learn about so I'd add that to the list, but SCRs are something I'd leave off.

[Anonymous No.1796128]

>>1796110
Yeah I had a feeling I'd needed to design complex outlines via AutoCAD and importing the resultant dxf.
Thought Altium would have some basic drafting abilities but I guess not. Thanks for the video though. I'll have to hunt down a copy of AutoCAD I guess.

[Anonymous No.1796150]

Anyone got some good websites and books to read about Electricity and engineering? I would like to make a hobby out of it and want to learn more. So far I got gaps in my knowledge of electricity

[Anonymous No.1796155]

>>1796150
Did you read the books in the OP?

[Anonymous No.1796161]

>>1796155
Probably should do that, but i'm mainly looking something more Physics based

[Anonymous No.1796164]

>>1796161
>something more Physics based
I'm a physics graduate, and what you've learned in physics will basically just be the opening sequence of electrical engineering, covering ideal circumstances. While these are useful in their own right, you'll need to learn the practical aspects and get yourself an intuition for the applying the concepts of electrical components. Something like the Art of Electronics will cover all the way from the most idealised circumstances to the most practical ones. If you already know something in it, just skim past it, but it's a very good book regardless of your knowledge. Might be a little advanced though, depending on what you've already learned. What have you already learned?

AoE was our recommended textbook for my 2nd year physics electronics paper anyhow.

[Anonymous No.1796204]

Do i connect the input audio jack ground to VSS or GND?

[Anonymous No.1796209]

is JLCPBC gonna have problems with this or am I worrying too much.
It's a 2 layer.

[Anonymous No.1796210]

>>1796161
>>1796164
Seconding AoE, have a CS&E degree and been working through it, it's fun.

[noko No.1796214]

Is using Lead HASL harmful? I know soldering and breathing the games probably is, but will manipulating or even licking the PCB result in anything bad?

[Anonymous No.1796216]

>>1796210
>>1796164
Not him, but how useful is Practical Electronics for Inventors compared to AoE?

[Anonymous No.1796220]

>>1796216
I think practical electronics is more aimed at the hobbyists who want a pretty good understanding to do DIY projects without going on the arduino forums to ask everything.
AoE is more academic, I feel. It might teach you much more in detail but you might also never have to bother with many of those details.

So it depends on what kind of learning method you vibe with more, but you might want practical electronics to get a good overview and then if there's something you're interested in learning more about you check it out in AoE. You can find both of them on the high seas.

[Anonymous No.1796228]

>>1796214
Don't lick lead you fucking dipshit.
Just wash your hands after manipulating it (like you should be doing after touching lead/tin solder anyways) or wear disposable gloves.

[Anonymous No.1796250]

When using an LC filter like those from https://rf-tools.com/lc-filter/, what happens when the input and input impedances are not the correct ones? Does it simply mean the Q of the filter will be different, or will I get reflections, signal distortion or other weird results?
I assume the output impedance is only at the range of frequencies that's are filtered, right? What if the input and output impedances are different at different frequencies?

[Anonymous No.1796259]

>>1796250
>Does it simply mean the Q of the filter will be different, or will I get reflections, signal distortion or other weird results?
yes
>I assume the output impedance is only at the range of frequencies that's are filtered, right? What if the input and output impedances are different at different frequencies?
>>1791214
R and G are usually really low so the frequency response is flat for most frequencies (well if you go high enough then everything is an antenna and it becomes a waveguide problem).

[Anonymous No.1796275]

>>1796204
I'd intuitively use GND, as it's generated internally as reference.
But I don't really, really know.

[Anonymous No.1796276]

>>1796259
Yes to what? Getting distortion?

[Anonymous No.1796296]

Funny story from an electronics website:
http://circuit-zone.com/index.php?electronic_project=627

"There are people who have “golden ears” and the feeling, provided that no application note scheme is never good enough for it to “Optimize” to “improvements” to make a claim. The problem is that most of them do not engineers and have no idea what the possible consequences of their “improvements” can be. For example, for a few years if these chips were popular with the audiophile crowd, it was all the rage at minimum power filter caps for “Best Sound” to use. We are talking about 500 uF on each power rail for each chip used LM3886 amplifier. This is clearly insufficient and leads to a distortion in the volume low enough that the power supply sags under load. The problem was that some of the golden ears of the large power supply rejection IC spec saw and thought it meant that the chip could tolerate the 10V power supply ripple. The pendulum has swung the other way, and now many music lovers are sufficient amounts of energy storage in the diet."

[Anonymous No.1796306]

>>1796276
All of the above. But remember reflections and other stuff only matters when the distances involved are similar to those of the wave (and the harmonics).
>>1796296
I remember a couple years ago there was a fad about discrete opamps being sold in very fancy metal cases and other shit. The things these people come up with

[Anonymous No.1796310]

Hey guys, I just got my hands on a 15MW synchronous generator excitation system, what are some cool projects I could do with it? Are there any guides on how to connect it to my arduino?

[Anonymous No.1796313]

>>1796306
It was something like this, not with metal but inside an acrylic bloc with LEDs and fancy pcb

[Anonymous No.1796317]

>>1796313
Audiophiles are probably the best cash cow for people who know enough about electronics to come up with shit like that that they can sell for crazy high prices with the simple promise of making the sound better

[Anonymous No.1796318]

how do I stop the inrush current pop in my audio amplfier when I turn it on

[Anonymous No.1796347]

>>1796313

[Anonymous No.1796352]

>>1796318
https://lmgtfy.com/?q=limit+inrush+current

[Anonymous No.1796383]

>>1796306
Another question, are reflections created when my signal source has a different output impedance than the transmission line?

[Anonymous No.1796394]

>>1796383
Yes, wherever there is impedances that do not match, there is the possiblity of reflection

[Anonymous No.1796465]

I have a wave gen capable of 10Vpp, 15MHz, and I need to effectively use this 4ohm, 5W transducer. What cheap amplifier will let me do this?

[Anonymous No.1796515]

>>1796465
Totem-pole made from high-speed BJTs (with heat-sinks), driven by a high-speed op-amp negative feedback loop. Assuming an H-bridge feeding it a square wave won't work.

[Anonymous No.1796523]

>>1796465
>>1796515
Actually I kinda want to do this myself, but I realise that my collection doesn't include any power transistors aside from a single spare TIP31C, and I don't have any power resistors in order to make a class-A. Normally I'd just take the hit and spend a couple of dollars at Jaycar, but I can't because they're closed for bat flu.

[Anonymous No.1796582]

>>1796523
Not him but if you have a hot air gun you can scrap the mosfets from an old PC motherboard and make a class B, they do OK at high frequency.
Mosfets in general tend to do better at high frequency than BJTs.

[Anonymous No.1796587]

BTW, a TIP31 will go to maybe 1 MHz with usable gain. Forget about 15 MHz.

[Anonymous No.1796593]

>>1796582
>Mosfets in general tend to do better at high frequency than BJTs.
For a few MHz maybe, but I'm pretty sure that gate capacitance becomes a big issue when you're dealing with RF. RF BJTs are the kind of thing I'd recommend using for such an amplifier.

>>1796587
It's just what I have lying around, and I just want to make such an amp for audio stuff myself. As a final stage for slapping a speaker onto a breadboard guitar pedal, or for otherwise driving something more demanding with my function generator.

[Anonymous No.1796605]

>>1796593
Oh nvm misread the question
Nah, the capacitance is not a problem. Mosfets are used in RF all the time. I know there are RF BJTs but they're special purpose and expensive, that's why I said "in general" meaning cheap general purpose devices

[Anonymous No.1796606]

You can make a class A amp with an inductor or coupling transformer in the collector rather than a beefy resistor

[Anonymous No.1796607]

>>1796606
I think I might have heard of those, that they can effectively double the efficiency of a class-A but aren't they only good at their specific tuned frequency?

[Anonymous No.1796619]

This Qcad thing is actually pretty cool, my first exposure to a properly designed 2D cad software. I was just going to use freecad for 2D and 3D, but then I saw that its circles were just many-sided polygons. And then I saw that they had 44 sides each.

[Anonymous No.1796744]

>>1796318
>how do I stop the inrush current pop in my audio amplfier when I turn it on

if you mean that the speakers make a loud pop, you need to make a time-delay relay that puts a power resistor across the speaker terminals for 2-3 secs after you turn the unit on, then switches over to connecting the speakers.
you used to be able to buy a factory-made timer in the old days, but no amp built in recent memory has that problem.

[Anonymous No.1796756]

>>1796582
>Mosfets in general tend to do better at high frequency than BJTs.
Not really. It's very curious because the working of FETs is always improved with lower frequencies and higher voltages. and 15MHz is barely "RF"(20 meters kek). It's really curious the direction where we are heading to lower voltages and higher frequencies. CPUs today run on what? 0.9V? If you start going past a few Gigahertz you'll start to see bipolar-like technologies again. (Heterojunction transistors and other weird things) but that's above us lowly hobbysts.

[Anonymous No.1796760]

>>1796605
> I know there are RF BJTs but they're special purpose and expensive
More like the oposite? Take a look at BJT-RF and MOSFET-RF in digikey. One costs 0.3$ the other 30$.
>>1796756
And is not about sticking up for your "favorite flavour" of transistor or technology, it's just that what you said is wrong and can be misleading.

[Anonymous No.1796765]

>>1796760
>https://www.infineon.com/dgdl/Infineon-RF+Discretes+Selection+Guide-BC-v01_00-EN.pdf?fileId=5546d46254e133b401552f3516a5698a
Just take a look at the catalogues also.

[Anonymous No.1796766]

>>1796744
Is that a memeristors near RL1?

[Anonymous No.1796846]

Good old friend 2N3055

[Anonymous No.1796891]

>>1795892
Getting closer, little by little. I replaced the CD40175 with CD4027

[Anonymous No.1796892]

>>1796891
Current iteration

[Anonymous No.1796894]

What is your go to power supply for little vero board projects? Are there any coax jacks that have standard pitch legs?

[Anonymous No.1796977]

>>1796894

9V battery terminals. solder one to your project, another one to your charger.
bonus: you can use an actual battery if the gadget can handle 9V.
pro-tip: get units made from solid plastic, not flexible cardboard.

[Anonymous No.1797052]

Is it possible to get oscilloscope hardware without the screen, that is fairly small?

Like one of those plug in tek modules, but is an oscope. I'm thinking of making a portable oscope with a crt viewfinder, but I want something with some power. I'd rather not sacrifice something like a tek210 for this. Composite out is a plus.

[Anonymous No.1797080]

>>1796891
Almost made it. Now only the green+yellow -> green transition happens instantly without fading off and on. Fading off after the green+yellow phase would require 11 counter steps but only 10 are available on the 4017.

[Anonymous No.1797082]

>>1797080
4017 controls the green light directly, red and yellow are controlled by the 4027 flipflop.

[Anonymous No.1797099]

>>1796760
Can you link to the specific page?
But that's kind of what I mean, and I was referring to power devices. Low power devices can be had for cheap with any kind of technology, but when you need to pump some power on HF you can pay 300 dollars for an RF transistor or mosfet or you can pay 20 bucks for a few IRF520s that'll do the job just the same (even though you won't find them under the RF section on digikey). Show me one BJT that'll go as high at the same price.
>>1796756
Yet you'll pay hundreds of dollars for an HF transistor.
Now when you get to higher frequencies then sure, you can't avoid paying out the ass because there's no cheaper alternative (except maybe those used surplus microwave transistors pulled from base station hardware that might or might not be burnt out).

[Anonymous No.1797100]

>>1796607
>but aren't they only good at their specific tuned frequency?
No, that's class D

[Anonymous No.1797103]

Although a class A with a single inductor (rather than a transformer) will be frequency sensitive (but not as much as a class D). A transformer on the other hand will work just fine throughout the spectrum (depending on the transformer's bandwidth).
Either of those have about double the efficiency from a resistor based class A IIRC. A class D would be even more efficient but only usable at one frequency.

[Anonymous No.1797242]

>>1797100
>

[Anonymous No.1797245]

Is there any difference between blue and green connection style for this decoupling cap and which should I use?

[Anonymous No.1797251]

>>1797245
Blue is shorter (better) but has a potential acid-trap (worse). I'd go for a hybrid between the two with that straight trace between C5 and that upper-right IC but a trace between the two ICs' pins.

[Anonymous No.1797262]

>>1797251
Doesn't the order matter? or does it not matter if I connect it like this?

[Anonymous No.1797264]

>>1797262
Order shouldn't matter, so long as your traces' ESR and ESL are negligible enough. Couldn't tell you for sure though.

[Anonymous No.1797274]

>>1797103
>A class D would be even more efficient but only usable at one frequency
what planet do you come from, i couldn't find any documentation alluring to a class-d's frequency dependance
with the exception of low-frequency distortion thanks to core saturation, which can be entirely mitigated through proper inductor selection

[Anonymous No.1797275]

>>1797274
wait that's meant to be alluding not alluring