/diy/ - Do It Yourself

Messing around with this circuit in hope of making an efficient flasher for my display. It's very dim at 1.25v. When I increase the voltage it's brighter but the LED stays dimly lit between flashes. I'm hoping to use a CMOS 555 and 3v cell battery to produce a bright flash every minute or so. Advice is appreciated

When Dave reviewed one of those cheap but good ANENG DMMs he made a huge deal out of missing 10mA and 100mA ranges. What's wrong with that? Does that mean that some resolution will be lost when, say, measuring 2mA on 1000mA scale instead of a missing 10mA or 100mA? So are we literally losing "counts" in this case and 20k becomes 6k or what? But most DMMs s in the 10k-20k count category skip some ranges, do they not?

>>2539954
That's a boost converter, so when it's turned off there will still be a nonzero voltage across the LEDs. If instead of connecting the LED negative line to ground you connect it to the positive leg of the PSU/battery, you end up with some sort of inverting topology. Pic related.
If you do go for a 3V coin cell, you likely won't need any boosting at all if you can go for parallel LEDs, though it depends somewhat on LED wavelength.

As for making the most out of battery life, consider the posts from last thread about flashing an LED to keep some phosphor glowing. Read: >>2538168 and the replies to it.

Need advice quick, can I use jewlery solder for wiring? Can't find anything online about doing that, just about pipe solder vs electrical.

>>2540029
I suspect that jewellery solder is the same as plumbing solder, a strong lead-free mix that needs to be soldered with a gas torch. If there are lower temperature ones that can be melted with an electric iron then go ahead, but as far as I know all electrical soldering alloys aren't too strong. Doubly so for lead-free stuff.

There won't be any electrical issues if that's what you're wondering. The only potential problems will be overheating of the surrounding components, or chemical damage due to a more active flux.

>>2540042
Thanks, just tried and it worked fine, rosin core which is apparently ideal.

>>2539950
Not sure if this i the right place to ask but I got a licor sensor for cheap and I want it to pull double duty to measure light flicker.
Is it just a simple as hooking it up to an oscilloscope for that purpose? I know it should produce a variable voltage even if it's not completely linear to the actual light hitting the sensor.
Pic related is what the actual sensor is

>>2540115
Yeah, though a DC-blocking filter followed by a true RMS AC measurement might be more immediately useful. Assuming TRMS is what's intrinsically useful when it comes to light ripple. Just measuring frequency and peak-to-trough amplitude would be really easy, though if you're getting really sharp spikes it wouldn't necessarily be indicative of human perception. Maybe a low-pass filter could try to mimic human light perception.

If the sensor is just a raw photodiode, you'll want a constant-current source or resistor on it, and to measure the resultant voltage. The size of resistor or current source will determine the effective sensitivity and saturation level of the sensor.

>>2540119
>If the sensor is just a raw photodiode
I think that is pretty much what it is, you're really supposed to be measuring current for the real lux value in which the simplest way to do that is actually measure the voltage across a 603 ohm resistor and doing some math. Doing that however gives a really pitiful voltage under 25mv
IDK if a higher value resistor would give a higher voltage more easily picked up by a cheap handheld oscilloscope

>>2540122
>IDK if a higher value resistor would give a higher voltage more easily picked up by a cheap handheld oscilloscope
Should do, but it may influence the sensitivity curve of the photodiode. A recommendation of 603Ω is probably for a reason. So maybe using a 40dB amplifier circuit is a better idea.

>>2539950
Hey I'd like to buy an esp32 chip and build my own pcb for it, any idea on how I can figure out what resistors/caps/crystals I need? Are those things usually in the datasheet for me to copy or do I need to calculate things?

>>2539954
If you want to flash the LEDs for a few seconds sparingly, you could try to look at charge pumps/voltage doublers. They don't require inductors. But if you need to power them for a significant time, you definitely need a boost converter like in your pic, then you need another control that controls the flashing..

>>2540155
The datasheet is a decent place to look, but existing circuits are a good idea also. Here's the schematic for the ESP-WROOM-32 module, and you can find the dev-board schematic that the ESP itself goes onto also. The dev-board has the USB-UART IC, a linreg, more bypass caps, reset and boot buttons, and a couple of transistors so the DTR and RTS signals going through the UART automatically put it in programming mode. Depending on how you plan on programming it those may or may not be handy.

After that I'd look at each part and cross-reference it to the datasheet. Like what the reset and boot buttons do, how much current the LDO needs to handle, what frequency oscillator you want, etc. Bypass capacitance is something you could probably ignore, but for good practice I'd read through that anyhow.

>>2540155
>>2540165
Here's the dev-board schematic. Also don't forget to buy the flash IC and ensure you can handle the RF PCB design. You may want to consider just using an ESP-WROOM-32 of some variety, because you don't have to worry about RF design, shielding, soldering the QFN, or the external progmem.

>>2540165
Thanks.

>>2540166
>buy the flash IC and ensure you can handle the RF PCB design
What do you mean by flash IC? The device to program the esp or some chip used in the circuit?
>ensure you can handle the RF PCB design
How challenging would that be if I just stick every component as close to the mcu as possible?

>>2540174
>What do you mean by flash IC?
Read the datasheet's section on memory, there's no internal program memory / flash. The chip requires a sufficiently fast external SPI flash memory IC to put programs on, as pictured here >>2540165 as U3. That flash IC is included under the metal can of an ESP-WROOM-32 module. The same applies to the ESP8266 and the RP2040.

>How challenging would that be if I just stick every component as close to the mcu as possible?
It's more about the antenna and getting the impedance matching. If you just copy the PCB design of a WROOM-32's antenna section you'll be fine, there may well be a section in the datasheet or in an Espressif appnote if you want to go more in-depth. At 2.4GHz the wavelength is 12cm, so the distance at which transmission line effects begin counting is about a tenth of that, or 1.2cm. If you cram things smaller than that it shouldn't really matter, though I'd consider using KiCAD's microwave toolkit anyhow, and following any given guidelines. Assuming you even need the RF capabilities in the first place.

I am desperate

I want to make a PSU to power a very small electrolytic cell. The cell uses a minute amount of current (a handful of mAs).

Problem is, the PSU needs to be battery powered (well this isn't really a limitation since I can use however many 18650s I want), somewhat compact, easy and relatively cheap to make and has to be able to have its output voltage adjusted down to the mV level.

Good news is I don't give a fuck about how inefficient it will be.

Would a simple voltage divider work for something like this? The output voltage will be somewhere around 0.2-0.4V.

>>2540181
lm317 with pot to adjust voltage

>>2540187
yeah but how will I get the output voltage down to the exact millivolt required?

like I need to be able to select voltages such as 0.223 or 0.224V, wouldn't it be impossible to adjust the pot to get the required voltage?

>>2540175
Ah I see. Both in the case of the flash IC and antenna, I wouldn't have to worry about it were I to use the following IC, correct?
https://www.mouser.ca/ProductDetail/Espressif-Systems/ESP32-C3-WROOM-02-H4?qs=stqOd1AaK79%2FSA14oWtR%252Bw%3D%3D

>>2540175
Ah I see. Both in the case of the flash IC and antenna, I wouldn't have to worry about it were I to use the following IC, correct?
https://www.mouser.com/datasheet/2/891/esp32_s3_wroom_2_datasheet_en-2902185.pdf

>>2540181
>>2540189
You need single millivolt precision? Then I'd find a voltage reference capable of that (tight tolerances, low drift, and low tempco), an op-amp with sufficiently low input offset voltage, and a multiturn potentiometer and/or a cascade of pots of different sizes for finer and coarser control. Use the trimpot as a divider after the voltage reference, and buffer it with the op-amp. And I guess add a sufficiently accurate voltage readout I guess, I'd either just plonk a good DMM on it when you adjust it, or directly use that reference plus a decent ADC and an MCU to drive a display. I wouldn't trust alibay panel meters, though if you only care about relative error they may be acceptable.

>>2540191
Correct. Assuming the extra width and height isn't a dealbreaker. There may also be models with no antenna and a mini coax port for it instead, if you want something ~15% more compact.
Haven't seen an ESP32-C3 module yet though, I'd use its schematic specifically (page 22). A quick glance suggests that the C3 might be programmable directly through a native USB serial decoder, that could be real handy.

>>2540189
I don't think you can achieve that precision with most lab bench power supplies. Perhaps an easier solution would be a redesign of your system? the more accurate you want the voltage to be, the more expensive it gets since you need more complex feedback systems and more accurate components.

>>2540194
so basically damn near impossible? the only voltage reference I can supply is a shitty 5V output

>>2540196
well I know but the chemistry of the cell is rather specific in its requirements and I will most likely have to look into that instead of fucking around with 1 mv PSUs

I need help to find the right transformer for the following IC
https://www.power.com/sites/default/files/documents/tinyswitch-iii_family_datasheet.pdf

Can someone teach me how to do this?

>>2540226
I looked through the data sheet, and it says the following:
>TinySwitch-III devices operate in the current limit mode. When enabled, the oscillator turns the power MOSFET on at the beginning of each cycle. The MOSFET is turned off when the current ramps up to the current limit or when the DCMAX limit is reached. Since the highest current limit level and frequency of a TinySwitch-III design are constant, the power delivered to the load is proportional to the primary inductance of the transformer and peak primary current squared. Hence, designing the supply involves calculating the primary inductance of the transformer for the maximum output power required

Does that mean that the primary induance L = Pout/(I^2*2*pi*f)? If we assume P out is 28W, that would mean the inductance would be 28W/(0.7^2*2pi*152000) = 60 uH?

>>2540226
https://www.power.com/sites/default/files/documents/an-90_tinyswitch-iii_family_design_guide.pdf
There is software on manufacturer's website that will give you required transformer parameters. Follow instructions until you get value for primary inductance and then find transformer that matches that value and can handle required power.
>>2540238
It's a bit more involved than that. Design is usually iterative process, because there are many degrees of freedom.

>>2540247
Thank you so much for your help.

In certain guitar amps you find valve pre amps with a so called shared cathode configuration. Basically two triode halves "share" their cathode resistor and cathode bypass cap (pic related left) The signal gets amplified by each half (in parallel) and the there is a slight difference in how they signals get filtered. One half has capacitors on the pots and mixer resistor so that the signal has way more treble at any time. The other half does not.

Now I wonder: Why would you need *both* triodes? They amplify the same signal before it gets filtered. Therefore should one triode not be enough? Pic related on the right.

Spice seems to agree with my theory, the difference in my simulation is really, really small. Amplitude and gain is basically the same, or actually even higher. Only frequency response differs very slightly at 5k and above.

So why is this done? Can anybody school me on this?

>>2540266
Just noticed that I fucked up the schematic, but it was correct in Spice when I did my simulation

>>2540266
Probably one of those audiophile marketing tricks like bias type switches to have more presence or "warmer more dynamic" sound. Reminds me of
https://www.youtube.com/watch?v=wcBEOcPtlYk

>>2540279
Everything in guitars is marketing anyways, so believing shit is deemed to failure...
That being said: I see why you would use two triodes in parallel if their resistors and bypass caps are different, because then you get different frequency response right there.

But with such a shared cathode setup?

>>2540287
>But with such a shared cathode setup?
It probably has something to do with distortion. For small signals there shouldn't be any difference in operation as superposition principle applies (confirmed by your frequency response simulation). But once you start having large excursions tubes will start influencing one another because they share current path. If you want to simulate this you can't use AC simulation in spice because it will automatically linearize circuit and won't use large signal tube models. You need to do transient simulation and then compare FFT results.

Can anyone recommend an offline converter IC with a universal input range of 80-265V that is very simple like the tny280 along with it's transformer part for a 20W+ output power.

Looks almost identical to me. Slight differences, of course. What do you think?

>>2540300
I'd consider pic related to be the same.

>>2540310
>>2540314
Only thing that matters here is if the difference is actually audible. There seems to be some difference in higher order harmonics, but whether that's significant you won't know until you build it.

>>2540316
Is one output out of phase with the other? Would the oscillation be perceived as a 'warmer' tone?

>>2540316
Thankfully, over the last few years, quite some people like >>2540279 have shown up and busted some of the religion that is this shit.
Which is why I want to actually take this to the next level. Sad thing is, that everything that you can read about this kind of stuff (be it online OR printed) is full of hearsay and make-believe. It's claims without anything backing up the claims.

Well, I'm done with this "just do it" attitude in guitars, which is exactly why I started questioning everything.

>>2540318
No, nothing is out of phase. Nothing is warmer here, I am not looking for warmth or anything like that shit.

Lots of devices in these teardown videos have too much room inside. The contents could have been stuffed in a much smaller box. Do they do this on purpose for high-end bench equipment to make it look bigger and more expensive?

>>2540357
>Do they do this on purpose for high-end bench equipment to make it look bigger and more expensive?

Sure. Everyone in the world is out to con you anon. Don't trust anyone ever.

>>2540357
The extra space is for shipping fentanyl. Look at the bright side. Shipping from chiner is cheap!*
*subsidized by US taxpayers.

>>2540357
the enclosures are probably just from another device that they already have the fab setup for that they decided to repurpose.
if it bothers you just buy the boards on their own and build your own enclosure.

>>2540357
Not wasting time on optimizing for space, or maybe better airflow.

>>2540221
>the only voltage reference I can supply is a shitty 5V output
No I'm saying you need to find a voltage reference IC/diode/whatever to put in your circuit. The typical TL431 has way too high drift and such to work, but it's just a matter of finding one that does work. Somewhat sensible values would be
> smaller than ±0.05% tolerance
> smaller than 25ppm/C tempco
For 0.5mV accuracy at 1V. If you need more or less than 1V output, you can scale those values appropriately. This one here is decent looking:
https://www.ti.com/lit/ds/symlink/ref35.pdf
And costs $5.50 each.
If you want to go to 0.01% tolerance and 5ppm/C tempco then you start running into trouble.

Personally I'd make something good to 3 digits of precision, since chances are you won't need any more than that. Consider if you really need both precision and accuracy.

>>2540308
Just go on a switching IC manufacturer's website and follow the instructions. Chances are they have online interactive tools and appnotes that help you select an appropriate transformer.

If you go for something variable frequency then you can basically use whatever transformer you want (flyback converters still need an internal air-gap, consider a forward converter instead). Personally I'd just power up a TL494 with a zener and go to town. A FET gate driver may be nice too.

Can you recommend a cheap FPGA development board for a homeless to learn FPGA programming?

>>2540476
You don't need a board to learn the basics. Get verilator to simulate your Verilog code. You can even download Yosys and generate a bitstream for random FPGA chips you don't have, just to confirm that your design is synthesizeable. Both are free software.

>>2540476
Start with a CPLD if you want to jump into the hardware now.

>>2540480
>>2540483
I need a development board, not a theoretical technology/software names.

>>2540492
Like I said, you don't need hardware to learn the basics. But I think a cheap Lattice board would do the job.

Why is it called a 100Ah AGM deep-cycle battery if you can only drain it by 60%? Just call it a 60Ah battery ffs.

Can I get some help? I can only post one image at a time but I’m trying to make this control board for a water flow meter work like it does in the vid:
https://m.youtube.com/watch?v=bvPP4wZlBUI

If I don’t have this wired by Friday I’m basically dead

If someone helps me I can pay $20-$200.

>>2540688
What's wrong with it?

>>2540688
Friday the 13th. Dead by dawn!

>>2540698
>>2540688
Can you guys tell me where I can go to have this done? I’d like to DIY but it really needs to be done by Friday and it’s not worth the opportunity cost to wait for DIY.

Can I just roll into my local electronics shop and ask them to do it?

>>2540688
>>2540709
Bunch of strangers on the internet won't be able to figure out how some random piece of equipment should be wired, and the same probably applies to professionals but you're welcome to give them a try. If it doesn't say in the thing's manual or in that youtube video you posted, it becomes a task of brute forcing it. By the sounds of things, you need to find what part of the circuit turns on when some sensor or timer hits a certain value, so I'd just take a bunch of voltage measurements across the board, then get the value above that, then measure again. See what changes. Though before that I'd try to look for a schematic.

>>2540700
I don’t know where to solder into. I have to solder some wires in to some switches. I’m a dogshit broke retard but if I can figure this out I’ll be making six figs

>>2540719
I couldn’t find a schematic, will a cheap multi work for this or should I get a nicer one? Thanks for the detailed reply.

>>2540719
I have a different flow meter control board I’ll look for a schematic tomorrow. I’m so invested in this working out, if you want compensation for 1:1 consultation I’d be more than happy. If I can’t figure this out I lose my house lmao!

>>2540719
Maybe I just need to buy a new board with schematics, idk. I’ll post my other control board tomorrow. There is a gun to my head on this stuff though, I didn’t expect to get stuck here.

>>2540754
Any old meter should be fine. But the multimeter technique only works for the output stuff, e.g. the switching of the output solenoid. Which I assume to be already in the wiring diagram.
But the input pressure switches are another thing. The yellow wires from one pressure sensor in the vid seem to go to an existing connector on the board (should be in the wiring diagram of your board), while the green wires from the other pressure sensor are bodged in parallel with what I assume to be the "run button". So if you can find that run button just solder the wires on the same two pins.

>>2540300
>distortion
Probably that, predisposing to a specific kind of harmonics.

Possible options in addition:
>RCA made it like that for some forgotten reason
And everyone basically copied after that...
>Preamp vales usually come in pairs, and since there isn't another use for the second side they just used it like that.

BMS anon back again. Work has been intense this week but I promise I shall complete the BMS PCB design and order all the parts.
I am having trouble finding 50mOhm shunt in my country with reasonable shipping cost so I'm being forced to use a track as the shunt. I'm also including a thermistor to measure the temperature of the "shunt" so that I can accurately measure the current through it

Hey guys, I need to sample two analog signals simultaneously (voltage and current) to find the power. I was thinking of using 1 adc with multiple channel, then sample the voltage on ch0, switch to ch1, sample current on ch1, switch back to ch0 and repeat the entire process at a specific sampling rate (at least 3500 samples per second). The question I had was whether this is possible using an ADC (such as the mcp3008), or is this not possible because of the delay between switching the channels? The sampled signal is then sent to the microcontroller for multiplication. I suppose the timing between the two samples don't have to be made at the same time, but must be made very close to each other to prevent errors in the computation of the instantaneous power. Is there a better way to do this (such as an analog multiplier circuit)?

>>2540985
>I am having trouble finding 50mOhm
Would your design allow multiple resistors in parallel to get 50 mohms? 2x100 or 4x200?

>>2540985
>I am having trouble finding 50mOhm shunt
You can probably get away with a semi-thin trace on a PCB, that's what chinky constant-current buck converters do. It won't be made of constantan, but it should be good enough. Make a milliohm meter for troubleshooting.

>>2540999
Analog multipliers are neat, but they're complex/expensive and don't allow for calculating other things like phase offset and sine quality. You'll need an anti-aliasing filter before the ADC anyhow, so if you end up having to sample on A then B then A etc. with 1ms between each sample, then you'll have an effective nyquist frequency of 500Hz, and would design the filter accordingly. Personally I'd go for a solution that lets you sample with at least a 5kHz nyquist frequency, as it gives you room for filter rolloff. An ADC with built-in filtering (like many delta-sigma ADCs tend to have) may be handy, and common audio ADCs are stereo anyhow, so might be a good choice if you can handle the bitrate and the I2S. An ESP32 would be able to do it easily.

>>2541069
isn't 1ms between each sample too long? Is there another way to do this with significantly smaller delay to allow a sampling frequency of at least 3500 (or 5k as you said, to reduce the order of the filter)?

>>2541103
>isn't 1ms between each sample too long?
It was just an example, read the datasheet of your chosen ADC to see how quickly you can swap channels.
>Is there another way to do this with significantly smaller delay to allow a sampling frequency of at least 3500
Don't use shitty ebay ADCs, use good ones with a higher sampling rate. They're still only a few dollars each. Heck, even the built-in ADC of modern 32-bit micros are far faster than 3500S/s. The aforementioned ESP32 can do 200kS/s, maybe 2MS/s if I'm reading it right.

>>2541106
all right, thanks. I'll take a look at the switching time, hopefully I don't have to spend too much money on the adc. I'll check out the ESP32, might go with that instead of the microcontroller I have right now.

>>2540764
If I take this to my local shop will they be able to figure it out? I just don’t even know where to begin here and really want it done.

>>2540155
>>2540165
>>2540166
I have a similar question. Specifically, the minimum for an esp32 to run. I would like to use something like picrel to flash bare modules and then solder a couple wires directly to the modules for power. Is this possible, or do the modules require such complicated circuits and components that it would be more effective to just buy a minimal board, or, are the castellated pins too small to solder with a basic iron? My main concerns are availability, cost, size, and ease of assembly

>>2541129
>I just don’t even know where to begin
Open mspaint and draw a schematic for over 9000 hours. You don't need to reverse engineer the PCB, just illustrate all the components of the system (solenoid, switches, sensor, etc.), and then draw the wires that connect them together. Your PCB has silkscreen labels already so it's only a matter of mapping it out.

>>2541132
And a followup question:
Does something like picrel exist for ESP32s, where I can clip on to a presoldered (or not) module for flashing, or is the pic from my previous post the closest I can get?

>>2540709
your friday deadline is impossible, even for professionals. And your 200$ wouldn't nearly be enough for said professionals, even if you gave them a week to do it. Your best bet is to replace the unit.

>>2541136
Those clips are garbage and oftentimes unusable due to spatial constraints. It's easy to solder/desolder leads clipped from THTs to the pins of the flash chip, with the other end of the leads soldered to a ribbon cable with some heat shrink on each for insulation.

i briefly overloaded (standard 250mW) pot and it gave out magic smoke and the smell is just unbearable but it is still working. Should I keep it or should I toss it? What is that smell from, will it go away? It is that typical smell of fried electronics but I can't quite describe it. What is it?

>>2541151
Throw it in the garbage. The smell is called electronigrosis and it never goes away. Now you carry the mark. You burned off the Soul-glo and oxidized the buttwipers.

>>2539950
is anyone else seeing REALLY fucking slow shipping times with LCSC? i've ordered from them before but it's never been this bad.

>>2541132
>>2541136
Crossposted to /mcg/
>>2541155
>>2541158

>>2540688
From the most recent youtube comments:

Solder to the pins on the back of the on off switch. The 4 pins are connected horizontally by traces on the circuit board. Solder one wire to the top pair, other wire to bottom pair.

>>2541159
The chinks are currently dying from the CIA variant. Operation Lockdown in effect.

Now you have an economy.
Now you don't.

>>2541178
that would suck since LCSC now stocks a bunch of MCUs at pre-pandemic prices.

Speaking of LCSC, is there a way to look up asian made analogs of well known popular opamps but at lower prices?

>>2541183
>pre-pandemic prices
https://www.youtube.com/watch?v=Ml6S2yiuSWE

>>2541132
Yeah that should be fine. The only requirement I can think of is the 3.3V power supply. They have a 1mm pitch between castellated vias, so it's not trivial to solder them. It's usually pretty easy to drag solder them on a board but when we're talking individual wires it might be a pain, but definitely still doable so long as you don't have too chunky a tip geometry. I'd advise having a vice and articulated hands/grippers, or equivalently useful workholding.

>>2541136
Haven't seen one before, chances are the castellated vias, when soldered, are too sloped and would have any clip just slip off. If you're making a PCB for one anyhow, put an ICSP header there somewhere. Be that UART or JTAG.

what's the grey goop used to prevent vibrations/shock from damaging big through board components?
any recommended brands?

>>2541207
Silastic. No clue about brands, but DuPont probably make it.

>>2541207
You can use 100% silicone sealant too.

>>2541132
>>2541194
From the more indepth research I've performed, it seems I need to tie the ENable pin to high and connect all of the ground pins

Can anyone confirm or deny whether ALL the ground pins MUST be connected for base function or if this is just a recommendation?

>>2541172
I read that one too a few days ago, but wanted to be sure. I'm now sure that's it and this is a super simple job now, but I gotta wait until my 24v solenoid valve arrives to complete it. in the meantime I'll be doing a simpler build with another flow meter and a 12v solenoid.

I got two of these. I'm not too familiar with EDLCs but these seem exceptionally shitty.

What kind of leakage is typical for one of these things? These take forever (literally hours) to get to a reasonably stable voltage on my bench power supply. When they do, they suck like 175mA They also start dropping in voltage, pretty fast, when removed from the power supply.

I charged one up to about 2.5V yesterday, to see what would happen when it left it alone. It dropped quickly from that, eventually slowing to a crawl and more or less stopping at about 1.5V. I haven't tested it properly, but their ESR is also really high. Like somewhere north of 400mΩ.

Does any of this seem at all normal or are these just basically trash?

Does anyone here have experience with siglent scopes? I need a portable scope and data logger for work, my first choice would be fluke, but a 125b is $3k used, I know that's a deal of the century for one of those (usually 5 grand lmao) but looking at the specs and more importantly how useful the scope is, it's kind of a heap of shit
>have to pay out the ass for the top level model just to get basic shit like cursors and zoom
>from videos looks like the screen refresh rate is something out of a early 2000s digital scope, so fuck all chance of catching transient events
>absolutely no deep memory/acquisition history
>no bus decode either (I also work on a lot of RS485 and CAN shit, though that doesn't really necessitate full isolation since it's all earth referenced LVDC anyway)
So I'm looking at getting a SHS1102X instead, but there is fuck all information on it, manual seems to suggest it does everything I need but not sure if it's actually decent or just a buggy turd like the rest of the chink desktop ones.

I want to control lights in my boat digitally from one control panel. How can I do that using wired connection? How this system is called? What products I would search?

>>2541333
See >>2540165, all the ground pins of the castellated vias are already internally connected together via the module's PCB. You can use that as a jumper if you're in one of those single-sided-board pinches, not that I'd particularly recommend doing so. I you need to pull IO0 high, maybe pull IO2 low and IO0 high also as per >>2540166, but I can't find any further info in the impenetrable datasheet so look for secondary sources on that.

>>2541353
High ESR is pretty normal for supercaps, but I couldn't tell you if that's a typical value. Find a datasheet for a similar sized cap and compare I guess. I'd expect them to not necessarily handle being charged up to their absolute max easily, but going all the way down to 1.5V does seem pretty extreme. Mighta got chinked and sold 1.5V caps? See if you can hook up a datalogger (e.g. arduino adc spitting out serial values to a text file) to plot charge vs voltage to see if it's linear like a capacitor should be.

>>2541364
Portable scopes have always looked pretty shitty. Chances are a name-brand USB scope will be pretty damn good since even chinky ones are usable, I'd just want to look into the software available for them, see what kind of reviews it has. Then I guess it's a matter of hooking it up to a tablet or laptop, maybe in some sort of TPU case (with extra battery).

>>2541370
A piece of sheet metal with a bunch of buttons screwed into it. With well stuck-on labels, maybe also some indicator lights if you want to get fancy.

What does phase 3/1 mean? I want to buy this boiler but don’t want a three phase unit. The website says they can be made single phase upon request but I’m looking at a used one. Is it doable to convert one to single phase?

>>2541383
> A piece of sheet metal with a bunch of buttons screwed into it. With well stuck-on labels, maybe also some indicator lights if you want to get fancy.
I said digitally, you blind motherfucker. One bus line that goes everywhere to which you eventually connect additional devices and create virtual switches.

>>2541385
Pic

>>2541385
>>2541388
it means it takes 3 or 1 phases you drop kick. you either wire up all 3 heaters in parallel or connect each one to a different phase, pic related took 30s to find the manual.

>>2541132
if you don't know what you're doing, just buy the fucking board

Wow super dead.

>>2541132
it would depend on the chip you're using. Some of them have all the components already built in internally (like the crystal, antenna, etc.) and require only a 3.3V, others need you to add extra stuff to it (antenna, crystal, etc.). So it really depends on the chip you select. But if you select the right one, then you can integrate it on a pcb with minimal components.

>>2541406
I saw that in the manual too but didn’t know what I was looking at. So it’s possible to run this on single phase?

In the stupid questions thread another anon said it means it’s three phase for the steam generator part, single for the motor.

And so the ability to run each separately as single phase, that’s true for all models under 30kw?

>>2541582

dude, go to the company website and chat with an operator (or the chat bot)
single phase is not the standard way these things operate.
if you want single phase, you gotta do a special order.
of course, you can hack a 3-phase heater into working single phase but the current rating will go way up, and it may be hard to find a source for it, unless you wire them in series, thus lowering total power.

>>2541582

dude, go to the company website and chat with an operator (or the chat bot)
single phase is not the standard way these things operate.
if you want single phase, you gotta do a special order.
of course, you can hack a 3-phase heater into working single phase but the current rating will go way up, and it may be hard to find a source for it, unless you wire them in series, thus lowering total power.

i'm thinking the real meaning of calling it 1/3 phase is
- it needs 120V single phase for motor/solenoids/sensors
- it needs 3-phase for heaters

>>2541609
>dude, go to the company website and chat with an operator (or the chat bot)
I'm going to (I have an email dialogue going right now), I'm just shitposting rn so I can ask an irl person more educated questions. Also, I can't afford a new one so I have to buy used. I will be running whatever steam generator I buy in an old dairy barn / weed grow op so I'm hoping I can find sufficient amperage, I'll be checking out the electrical potential more tomorrow before moving forward with anything. Thanks for the help, I just don't want to potentially damage the unit by hacking it to run single phase. There's one going for under $200 at an auction right now and I might snag it since these are normally several thousand.

new ic idea:
like a window comparator but with an sr latch
i call it a window latch
fits in an 8-pin package, dual fits in a 14-pin package

Do you guys prefer AC or DC shocks? I like AC, it's like you're riding the wave.

>>2541621

pretty original.
you could call it an NE666 (the beast) or 668 (neighbor of the beast).

>>2540268
>>2540266
well you'd have one tube driving a ~500k load instead of each driving a 1M load
seems like a buffer to me

>>2541692
Shame that the 555 only works for it if one threshold voltage is twice the other, and the you just need one output topology.

my friend and i were talking tonight and had an invention. what if instead of tying your tubes you just had a bluetooth clamp on your tubes that you could elect to close or open depending on the circumstance? it could even have a drain valve and mircopump so your balls are still functioning proper, it's just like a redirect.

>>2541838
maybe even just like a micropiston that puts a micron filter in place that doesn't let semen pass through, then exhaust the dumplings?

>>2541838
where does the power come from?

>>2541842
Not that guy but
Piss turbine

OK, I found myself >>2541370
It's called backbone bus line and the standard protocol is called NMEA 2000, there exist working solutions already. Fuck you all for ignoring the question.

>>2541846
You're talking to a bunch of EEs and wannabe EEs, not marine autoelectricians. Maybe one anon here might have heard of NMEA 2000, if you're lucky. Probably more likely to get positive results on /o/ or whatever board yachties hang out. This is a general for nuanced problem solving, not for figuring out which obscure existing product suits your needs. Not our fault it took you a day of googling to figure out that "marine can bus protocol" are the requisite keywords.

>>2541842
yeah either piss turbine or solared powered on your bald spot. you never get laid any so it's not like matters

>>2541846
>reeeee I didn't receive free consulting services from expert marine electronics engineering consultant on obscure mongolian basket weaving and tapestry board aimed at hobby electronics
Are you retarded?

>>2541698
I did not think of that and there does not seem to be a difference in the sim, but this seems at least somewhat plausible. However, the load can be changed accordingly.

>>2540972
>>distortion
>Probably that, predisposing to a specific kind of harmonics.
This circuit was first deployed in amp in the 50ies when they were designed *not* to distort. Also this is the very first valve in the circuit, it does not overdrive under normal circumstances anyways.

>>RCA made it like that for some forgotten reason
>And everyone basically copied after that...
Yeah, this kind of stuff always happens
>Preamp vales usually come in pairs, and since there isn't another use for the second side they just used it like that.
But they needed a) more parts and b) more complex wiring which does not make sense.

I am actually going to try it out, but I won't be able to in the next four weeks thanks to work. But we'll see (or better hear!) the difference eventually

Best budget 12v 30Ah lithium battery?

How do MCU integrated DACs compare to standalone DAC chips with the same resolution and the same external voltage reference? Is there any reason to avoid the internal DAC?

>>2542001
compare datasheets and chip prices and use your fucking brain

>>2542001
Normally you'd use a dedicated DAC for finer accuracy and precision, or high-frequency signals.

https://www.digikey.com/en/articles/know-when-how-to-choose-apply-external-dac-for-microcontroller

>>2541756
>Shame that the 555 only works for it if one threshold voltage is twice the other
fucking what? you can manually set the control voltage right there

>>2542006
ok that's good info, comparing what i have, some STM32 chips and some external DACs, the main difference is the latter are "rail to rail", while the internal DACs are typically 0.2v to VCC-0.2v. And also the Vref min is 1.8v that's bad, I have a 1.25v reference. As for differential and integral non-lineariity they are pretty comparable and in some way the internal DACs are even better.

>>2542007
But the other comparator threshold is still at half the CV

I like using the CV pin as a Bias voltage source in minimalist circuits.

>>2540357
>That microwave inducer right next to 3 big caps.
That kind of enclosure is to help it cool. You put that in something the size of a VHS case it will smell all day from trying to burn a hole through the side. I don't see a fan in there to help that, so the space is big.

>>2540357
>>2540380
>Do they do this on purpose for high-end bench equipment to make it look bigger and more expensive?
>>2540397
>the enclosures are probably just from another device that they already have the fab setup for that they decided to repurpose.
>>2540402
>Not wasting time on optimizing for space, or maybe better airflow.
>>2542041
>That microwave inducer right next to 3 big caps.
>That kind of enclosure is to help it cool.

All correct.
>How many birds can you kill with one stone?
Cheap, ready to go, surplus enclosures from another product.
No time spent designing, no time spent optimizing, cheap.
Pick an oversized one, it'll look fancier/more expensive, it's easier to fit everything inside so it'll be cheap to adapt, and it's easier to keep everything cool.
>Downsides?
Shipping Prices
>Insert bug laugh

I'm building a plant waterer with a nodemcu, soil moisture sensors and pumps inside a water container (for 4 different plants). I know I shouldn't power a motor through a microcontroller pin, but I'm not so sure if I can share the power supply (it's a 5v phone charger). Am I doing it right?

Also, I'd like to check if there is water in the container (because the pumps are not made for air) with just 2 cables touching the water and checking for current, but I'm afraid that the pumps powering on (5v) will send power to the microcontroller pin (3v3) though those cables and smoke the nodemcu.

>>2542069
For similar tasks, I always use the cheap dual-mosfet sluts from Amazon, you can find 'em for as little as 30cents a piece.
You can use them to switch power, or drive them with PWM to control speed.
https://www.amazon.com/s?k=dual+mosfet+driver+400w+pwm
The ratings are pretty much bullshit, but they're inexpensive, versatile, and easy to use.

Actually good reviews with real information in them:
https://www.amazon.com/gp/customer-reviews/R1OZPBAMZJKNK2/
https://www.amazon.com/gp/customer-reviews/RPAD4SU1XF9JF
https://www.amazon.com/gp/customer-reviews/R2JHQFE7O8GAJQ/
Bonus:
>I'm using this as a pump controller for a 3D-printed tower garden.
>Includes video and oscilloscope shot
https://www.amazon.com/gp/customer-reviews/R3N9536NYDD18Y

Here's a 24 pack for $7: https://www.amazon.com/gp/product/B0B6J1MZC2

>>2542069
For your level sensor, check this out:
https://circuitdigest.com/microcontroller-projects/interfacing-water-level-sensor-with-arduino

They don't just go over using a generic Arduino sensor, they actually explain how it all works from top to bottom, including a schematic of the generic Arduino "water sensors."
Top-notch shit, genuinely, go read it.
>In the schematic, the collector of the transistor is connected to the supply voltage of 5V, and the emitter is connected to the ground with a 100 Ohms resistor. In the module, a set of 5 conducting plates are connected with the vcc in series with a 100 Ohms resistor and the other 5 sets are connected to the base of the NPN transistor. Now when the water touches these conducting palates, currents start flowing from the 5V supply to the base of the transistor, and the transistor turns on. The more submerged the sensor is, the more output voltage it will generate.

>>2539950
Where is that image from?

>>2542095
google images

>>2542041
>microwave inducer
wait, what? that's a teardown of a bench dmm.
what's a microwave inducer, anyway? and why would a dmm need one?
>I don't see a fan in there
there is a fan (yellow wires on bottom left), it is hard to see from that angle, and i was wondering why the fuck do you need a fan in a dmm??? you don't want any kind of a heat source inside the box to affect accuracy of a 6.5 digit dmm. and honestly it is an inherently low power device. it is not a dummy load ffs.

>>2541387
Switches are digital you dumb motherfucker.
You didn't tell us you wanted one bus wire.
What user interface do you want to use to control all your lights?
You're not off to a good start with the attitude.

I got a new multimeter. When I touch the probes together when set to voltage AC it detects 0.004 voltage. Shouldn't it be zero? I also tested it on wall sockets. It sometimes reads a different value in the same socket. Not different by more than a volt or two though.

Does this mean it's not an accurate meter?

It's a kaiweets ht118A

>>2542237
>When I touch the probes together when set to voltage AC it detects 0.004 voltage. Shouldn't it be zero?
There will always be offset voltage by nature of how the multimeter works.
In certain cases, it can be accounted for and even "removed" (more like hidden) with calibration.
This isn't an unusual behavior for multimeters.

That said, you bought a cheap chinese multimeter that has a reputation for being unreliable when measuring anything AC.
Might not be a good option for your use.

>>2542248
I am still in return range. What other options are good? Auto ranging would be nice. Not trying to go super high end right now. Would like something cheaper that would make a good beat along side a higher end one when I upgrade. Autoranging would be nice.

>>2542249
For a similar price, I'd consider the Mestek DM100C.
https://www.amazon.com/Multimeter-MESTEK-Capacitance-Resistance-Temperature/dp/B0B1WMYZ5S
It's still an inexpensive Chinese multimeter, but it's a little teeny bit more versatile, a little teeny bit more accurate (supposedly), and in my opinion an overall higher-quality and better made unit.
It's definitely not a premium multimeter, but for $5 more than the HT118A you get a lot more than $5 worth of quality difference.
It's also not challenging to recalibrate it if you ever have the opportunity, a lot of other Chinkanese multimeters either don't have the ability or just don't publish the calibration procedure.
For the price range, it's definitely my top choice, I'd trust it over a lot of other similar meters.

>>2542261
The kaiweets had a 13$ coupon so that one is more like 20$ more.
I paid about 15$ for the kaiweets and with the 5% off coupon the mestek would be about 34$
How much higher would I have to go for an upgrade over that?
How is this harbor freight one?:
https://www.harborfreight.com/electrical/electrician-s-tools/multimeters-testers/11-function-digital-multimeter-with-audible-continuity-61593.html

You know how a conventional “modified sine wave” inverter’s waveform isn’t a square but rather has a flat spot in the middle? How would you do that with an H-bridge? Just leave both halves floating? Because I think you’d end up with massive silicon-destroying spikes, or at least body-diode conducting thermal problems. The other option is to pull both halves low, but that would apply a braking force.

>>2542269
$10-$15 is a HUGE jump in price range when it comes to these things, lots of manufacturers with options that are only separated by a few bucks here and there, where the higher end stuff sees much wider deviations in price.
For anything less than the $23 of that Harbor Freight option, that HT118A is a fuckin' GOAT and would be damn difficult to beat without jumping to the $30-$35 range. It kicks the shit out of that Cen-Tech Harbor Freight cheapo.

I've seen ANENG AN8008 for $20 before, very very good if not very feature rich, but right now I'm only seeing it for almost $30 on Amazon and that's overpriced in my opinion.
The Mastech MS8222G is another great option for that lower ~$20ish price, but yet again I'm only seeing it now for closer to $30 and that's too damn much when the DM100C is $34.

If you hadn't specifically mentioned A/C I'd be damn tempted to say you got that HT118A at a great price and should keep it, but it really does have some latent issues that shouldn't be ignored if line voltage is what you're using it for.
For automotive or similar use, DC all day, damn good deal you got there.

>>2542269
Are you in the US?
https://www.mpja.com/Palm-Size-Digital-Multimeter-4-Digit-9999-Count/productinfo/35524+TE/

$26.95

>>2542278
Bought it for Automotive and electronics. Was just testing it on the power sockets. If it's good enough to tell me the power is off and I won't die when swapping one out it will do 99.9% of what I would need it to do with line power. Not even sure what else I would use it for? Diagnosing abnormal house circuits?

Out of curiosity what would I get with going another 15-20$ over the mestek? Like 40-60 range?

>>2542288
Am in the US. Definitely want capacitance though. Appreciate the help though.

>>2542291
>Definitely want capacitance
I'm litch-ruly (that's how faggots pronounce literally) crying rn because you didn't even read the specs. You hurt my feelings, Anon.

>CAPACITANCE
>Ranges: 9.999nF Accuracy: 5% + 20 LS Digit
>Ranges: 99.99nF, 999.9nF, 9.999uF, 99.99uF, 999.9uF Accuracy: 2% + 5 LS Digit
>Ranges: 9.999mF Accuracy: 5% + 5 LS Digit

>>2542292
Ah shoot. I misread, I am very rusty for electronics at this point and somehow managed to mistake the capacitor symbol on the unit for something else. Sorry anon.

>>2542293
I was just busting your balls, Anon. I don't really have any feelings anymore. lmao

Treat your mother right.
https://www.youtube.com/watch?v=RO6JiFztJdg

>>2542291
Once you're spending that much, you can tickle the balls of the lower-end offerings from some serious brands.
Fluke 101, Greenlee DM-45, Extech EX330, Klein Tools MM600.
These are top-tier brands, these are guys you can feel comfortable buying a $600 multimeter from.
Some, like Extech, offer some low end stuff, but if you're spending <$50 you get more bang for your buck with the Chinese stuff.
When you want to step into serious quality and are willing to spend -at least- $50, then you know you're getting what you pay for with some of these big serious names.
Fluke and Klein are ubiquitous with multimeters.
I could give a shit about their $10-$35 stuff, but once you pull your wallet out it's hard to beat the big names.

>>2542307
Thanks for the blanks. I was looking at a 50$ klein one. I do need one for both automotive repairs plus diy electronics and repairs. I was thinking about just keeping this one as a cheap beater for the garage since I won't care too much if it falls from the lip of my engineer compartment and breaks or something and getting a much nicer one for electronics.
Will there be much of an advantage of using the nicer ones for automotive?

>>2542322
brands* damn tired brain.

Is there anything wrong with using bridge rectifier for dual supply AND also V+ to V- single supply in the same circuit? The single supply will see two caps connected in series? Any issues with that, since they are connected to the center tap?

>>2541846
NMEA 2000 is standard CAN bus with its own protocol. Some work has been done in deciphering it, otherwise the spec is like 10k to purchase. Controlling lights is weaksauce, feed engine data or control nav equipment.

>>2542333
You mean just draining from the + rail with respect to the ground of that pic? Yeah it's fine to have unbalanced currents with that circuit.

>>2542016
CV, Trig, and GND nodes are all accessible, just add an external resistor in parallel to modify it

>>2542429
No, V+ to V-. Two loads: one is dual V+ to ground, V- to ground, and the other one is V+ to V-.

Any recomendations on how to learn to repair old motherboards/ pc boards?
I have some very specific equipment that I would like to restore. I know how to solder and desolder and to design my own circuits, but when it comes to this I have no idea where to start looking

>>2539950
anyone try to make money selling shit. i got some ideas for expensive but i think good for maybe a test rig projects that dont currently exist. probably sell it for 400$ with 200$ worth of parts plus pcb
It similar to something i made at work for a one off project so i was thinking of recreating at my house it and selling it privately. of course you would also need to make a test rig to verify it and test it but this is feasible.

>>2542529
yeah that's fine.

>>2542557
dabbled in it, but only for cheap stuff. would use jlc's assembly service if i actually wanted to sell significant quantities of anything.

Would this kill my opamp? Is this a good way to save power on a battery powered circuit? I am using the amplifier in a differential amplifier config.

>>2542677
>Would this kill my opamp?

no, bipolar parts are indestructible.
CMOS parts arent but can still more abuse than a meth prozzie.

>Is this a good way to save power on a battery powered circuit?

best way is to pay a few dollars more for a very low-current part like the LPV802DGKR (320nA)

Behold: breadboard compatible BNC connectors.

>>2542742
wtf lmaocopter

>>2542742
Can I get a breadboard compatible MCU mount? Thanks.

>>2542768
Just design your own breakout board and get it fabricated, bro.

>>2542742
wtf why haven't I seen RF components on a breadboard before??

>>2542542
a tech expert told me about baking computer components in the oven to fix them for a more or less temporary time. It was done with fruitBooks before pawning them off to the hopefully last user, but have fixed graphic cards as well. Apparently it wasn't about reflowing broken connections as the temperatures were way below the melting point of solder so it should be safe to try out but remember to keep the room well ventilated and you might not want to bake cookies while you're gassing out electronics.

Another approach is finding service manuals and equipment for testing caps transistors besides continuity and voltage. Older boards may have bare pads for diagnostics of whole sections of the board but it is uncommon now a days.
Depending on what you are working on Usagi Electric could be of interest.

>>2542804
I think it's fractured traces/vias from thermal expansion and contraction that are temporarily fixed by baking the board in the oven. Just my guess.

>>2542810
Another guess is releasing helium gas which is known to get stuck in chips and screwing with the electronics on the atomic scale.

>>2542779
Do you even know why people use breadboards instead of immediately fabrication of your attempts?

How do you select the right OpAmp for your need ? Doing Bode diagram each time ?
What are the most common "Jackofalltrades" OpAmp for a Signal beginner ?

>>2540357
That transformer is probably quite electrically noisy and also gets hot so giving it space is an easy way to increase the performance of the rest of the device. Having a fat transformer box on the power cord besides a slightly smaller equipment box isn't what the customer prefer.

>>2542840
>"Jackofalltrades" OpAmp for a noob

741
324
TL022 or TL072 or TL084
bonus:
LM386 for driving speakers or headphones
NE5532 for super low-noise

all of these are older than you, but will still be around when you reach 100.

>>2540165
>>2540166
Do you know if the following chip needs a USB-UART programmer?
https://www.espressif.com/sites/default/files/documentation/esp32-s3-wroom-1_wroom-1u_datasheet_en.pdf

According to the datasheet, it has pins io19/io20 for USB d- and d+, but the esp max voltage is 3.3v while usb is 5V. Can i connect the USB datalines directly to io19/io20 or do I need some usb/uart bridge? Any schematics for a non qfn package (either through hole or surface mount with easy to solder pins)?

>>2542677
If you take the LMV358 RRIO op-amp as an example, the maximum input voltage is just 5.5V, not something like "Vcc+0.7". But when you look at the functional block diagram you can see that there are diodes from the inputs to the inputs to the power rails. So that ~1.6V would end up going into its power supply, which I assume is undesired. If you can find an op-amp without input protection diodes though it should work, as the PMOS input topology should be intrinsically tolerant to voltages above a supply rail. The same should apply to a CMOS op-amp I think, but they're probably also more likely to have input protection diodes for ESD reasons.

>>2542840
Best to have a series of decent ones. I say at least these three categories:
>general purpose - cheap like LM358
>audio - a JFET op-amp like TL072 or OPA2134
>RRIO if you do LV digital projects - something like an LMV358
Ground sensing op-amps (LM358 included) are really handy for current sensing purposes, though that usually overlaps with RRIO op-amps. Watch EEVblog's video on jellybean op-amps for more. Get general purpose and maybe RRIO comparators too.
Then maybe you plan on doing stuff that needs a really low input offset voltage, or really low quiescent current, or low noise, or can handle really high frequencies. At which point you'll need to look for more special-purpose op-amps.

>>2542856
USB data lines are at 3.3V anyhow. You'd just connect the data lines directly (maybe through resistors, maybe with TVS diodes, read the datasheet). If you also want to power it off USB, then use a 5V to 3.3V regulator from the USB's 5V power rail, not forgetting the filter caps.

As for whether they can be programmed directly through USB (i.e. without UART or JTAG), a quick look suggested it might be possible. But the pictures of ESP32 C3 dev-boards I can see seem to have two USB ports, one for direct connection to use as a keyb controller or whatever, and the other probably connected to a UART IC for programming.

>>2542870
>USB data lines are at 3.3V anyhow. You'd just connect the data lines directly (maybe through resistors, maybe with TVS diodes, read the datasheet). If you also want to power it off USB, then use a 5V to 3.3V regulator from the USB's 5V power rail, not forgetting the filter caps.
I read through the datasheet and it's not very clear. They seem to have included the circuit with the crystal, antenna, etc. which is supposed to already be integrated on the chip. I hope it's not too much to ask to help me find it? Is it pic rel?

>>2542876
That's the 32k crystal for the RTC I think, the 40MHz crystal is on the WROOM board but the RTC crystal needs to be external. That's definitely a circuit with a WROOM board, and it definitely has USB going into it, though it has two different programming methods (UART AND JTAG) already on it so it's hardly specific. Also it's the S3 not the C3.

Connecting USB directly to the board seems mainly designed to use the ESP32 as a piece of USB hardware, not for programming. Then again reading this:
>https://github.com/espressif/arduino-esp32/issues/6762
Suggests it is possible to program the ESP32S2 and S3 over USB, though it may be buggy. Read through that thread and reference the datasheet, they seem to be referencing built-in JTAG hardware connected directly to the USB hardware.

>>2542785
>wtf why haven't I seen RF components on a breadboard before??

Probably because random wires looping all over the place is hell on RF circuits.

>>2542886
>That's the 32k crystal for the RTC I think, the 40MHz crystal is on the WROOM board but the RTC crystal needs to be external. That's definitely a circuit with a WROOM board, and it definitely has USB going into it, though it has two different programming methods (UART AND JTAG) already on it so it's hardly specific. Also it's the S3 not the C3.
is the RTC required for the operation of the esp32? Can I just not include it? Also i'm not familiar with the JTAG workaround. Would that require me to use some usb/uart bridge?

Sorry in advance if I sound like a retard, I am in way over my head on this. I am trying to figure out the inductance of a dual voltage 9 wire 3 phase AC motor and I'm not sure if I am understanding this at all. Am I right in saying that this is a star configuration motor because it can be used with two voltages? It seems to me that the wiring for the low voltage configuration is an industry standard where the wires labled t4, t5, and t6 are connected together, and then t1 is paired with t7, t2 is with t8, and t3 is with t9. How can I measure the inductance when it is in this configuration? I don't really understand the explanations I see online, where a lot of them talk about three terminals, usually labeled a,b, and c. I assume that those are refering to t1, t2, and t3, but do I want to keep t1 paired with t7 and so on when I do this? I don't know why, but something seems wrong about that to me. Also, how would I connect this to a motor control board? I want to use this as an improvised servo by attaching a rotary encoder, and I need to know the inductance in order to make sure that the motor controller I have eyed is suitable.

>>2542889
I suspect he was joking

>>2542895
>is the RTC required for the operation of the esp32
No. It's used by the watchdog timer to while sleeping the processor for power saving, to turn on again after a set long-ish amount of time. If you're not using that then it doesn't matter. You can also ditch the JTAG and just use UART for programming, or vice-versa. That schematic was just showing a bunch of different peripherals you might want to have.

>>2542908
>Am I right in saying that this is a star configuration motor because it can be used with two voltages
It's a star configurations because there's a centre connection. It can be used with two voltages because they've split each winding into two. Either of those features can be present without the other.
>How can I measure the inductance when it is in this configuration?
You can't, because the windings are all connected together. You'd need to remove those connections before measuring. There should be a user-serviceable wiring box of some sort.
You may be able to do the measurements anyhow and calculate back what the equivalent single inductance should be, but that doesn't sound trivial. It might also be possible to calculate the inductance from the rated current at a known frequency, and probably also the ESR.
>numbers
Not sure, but they may well not be standardised. Follow the documentation for your motor in particular over anything else.

>>2542924
>they seem to be referencing built-in JTAG hardware connected directly to the USB hardware.
So could you just confirm if the following is correct?

if I wanted to program the esp with a usb connector (from the computer), I would connect the D-/D+ like pic rel to IO19/20 (and the 5V power to a 3.3V regulator + tvs diodes and caps on d+/- lines), then would have to set the esp32 to operate in jtag mode? And to set the esp32 into jtag mode, i have to pull some IO pins according to page 11-12 of:
https://www.espressif.com/sites/default/files/documentation/esp32-s3-wroom-1_wroom-1u_datasheet_en.pdf

So to set JTAG to the usb serial, I'd pull GPIO3 high and connect D- and D+ of the usb port to IO19/20? And by using the JTAG controller, the issues you highlghted in https://github.com/espressif/arduino-esp32/issues/6762 no longer applies correct?

I just want to say I really appreciate your help. Thank you very much.

Two pictures, three questions.

First off, I need to solder wires to these tabs. The plastic looks like it'll just melt if the hot iron even gets near it. Any tips/suggestions for preserving the plastic? The shape isn't exactly crucial, but it's a vintage turntable and getting a replacement will price me out and force a jury rig that negates the detachable headshell.

Second, the wires that were originally hill were indescribably thin, and were two twisted pairs. Do I need to recreate the twist? Most of the length will be in a tonearm that I believe is aluminum or at least metal, if that matters.

>>2542785
Mercifully I'm only interested in mechanical frequencies, which are orders of magnitude less than RF.

>>2542952
Secondly, on the right side of this image, you can see two terminals for soldering the ground leads for either channel of the cartirdge signal that then have wires going to the jacket of the RCA jacks.

At the base of the white bracket the terminals are mounted to, there are three other terminals - one soldered to a wire that goes to the pre-amp grounding wire. Should there be a wire on the empty terminals that goes to the ground terminals as well? Perhaps they're grounded to chassis via the RCA jacks?

And it's a dual 1009 ripped out of a console before I bought it (for too much, in retrospect) if anyone is curious.

>>2542952
Well if the plastic is that sensitive you have two options: 1 avoid soldering by using aligator clips or drilling a hole and then twist a wire around it
2. if soldering is a must, then your best bet is to minimize temperature and soldering time. To do so, first make sure that you use lead solder, not that lead-free crap since it requires higher temperature. Second, make sure to prepare the surface. it looks like this contact is corroded. So sandpaper it, then wash it as best as you can to make sure it takes solder easily and reduces the time it needs to be heated up. Second, try to solder as far away from the plastic as possible. If you can, try to solder on the top edges, since it will increase the time for the heat to transfer to the plastic. Finally, make sure that your wire is tinned properly before soldering, since an untined wire will increase solder time. That is all of course assuming you can't remove the plastic and can't buy spares if you screw up.it might also be useful to perhaps somehow cool the connector (bag of ice maybe?), just make sure that the water won't damage the connector. Try to also limit the amount of time you solder. If you see it's not soldering, after a second or two, stop and let it cool down, then prep the area again (sandpaper, flux, etc.) and try again.

>>2542952
solder wires to a metal sheet. Rivet the metal sheet to connector. Report back on if it worked.

>>2542964
Thanks! I do feel that soldering is necessary in order to keep a positive connection and for space reasons.

>>2542975
My fault for not giving any sense of scale, but those tabs are only a couple of millimeters wide. Also, I don't have any riveting hardware and I'd like to keep the cost down.

>>2542945
I'd generally not put caps on the d+/- lines, just caps on the power rails. Though some further reading (https://github.com/myelin/modular-arm-usb/issues/7)) seems to suggest that it's not a stupid idea. If you're making a PCB, make footprints for them and leave them unpopulated unless you get issues. Could add a jumperable footprint for a series resistor also (e.g. one with pads really close together so you can jumper the footprint with a solder blob). Same for the TVS diodes, they're a nice thing to add for a design that's more resilient against ESD and circuit faults, I'd make the footprint but leave it vacant unless you happen have the parts lying around. If you're proto-boarding things, then it shouldn't be too hard to modify your circuit to add caps and ZVS diodes, assuming they even make THT ZVS diodes.

FYI a common and cheap linear regulator used by lots of arduinos is the AMS1117-3.3, though I'm unsure how much I trust the ones from alibay (lost an AVR to one) so get them from a good source. If you want to run it off a lithium cell, then an HT7333 would be a better choice for its extremely low dropout.

>then would have to set the esp32 to operate in jtag mode
From what I'm reading It's probably a hardware bug with the S3, but the but isn't there for the RISC-V C3:
>no other ESP32 has this issue (original, S2, C3 etc)
So just following the instructions that lead to the problem in the first place:
>USB mode = USB-OTG
>USB CDC on boot = enabled
>Upload mode = USB OTG CDC.
Should do the job. I assume those settings are accessed in the tools dropdown of the arduino IDE.

>>2542952
As the other guy said, soldering for a short time may be the way to go. High temperatures and extra flux are what I'd recommend. Nothing wrong with lead-free if it's a bismuth alloy.
That or get/make a lipo spot-welder and solder onto some nickel tabs.

I'd keep the wires twisted.

Where can I find a reliable source for wire amperage? I have 22 AWG stranded wire that I want to use for a pump that needs about 3 amps at 12v and the distance to the pump is about 2-3 meters, so about 4-6m total wire there and back. The pump will run max 10 or 20 minutes every few hours.

I took a small piece of the wire and ran 3 amps through it with my bench power supply in current limit mode and it didn't seem to get warm or hot within a minute or two.

The values on the internet for wire amperages are are all over the place, from 0.9 amps to 7 amps. My guess and gut feeling is "it will probably be fine" but I'd like to know for certain because this thing will run unattended after I've tested it.

>>2543091
use highest awg per current requirement, then go one step further. you should be fine

>>2543091 (me)
>>2543101
Doing some calculations I should be fine apparently, but it's not optimal. Voltage drop at 12v for 6 meters of 22AWG copper wire is about 0.954V or 7.95 %. The membrane pump will work fine. I read that I should ideally aim for 3 % voltage drop or less and max 5 % (no idea how reliable this info is).
>20AWG would get me to about 5% voltage drop.
>18AWG would get me to about 3% voltage drop.
>16AWG would get me to about 2% voltage drop.
I'll measure the voltage drop once I set it up and can test it. I'm not quite sure if I can trust my Chinese 22AWG wire to be 22AWG. Even so I'm pushing it but as I don't run it 24/7 it may be fine.

>>2542840
i like the LM324/358 because it can sense really fucking close to the gnd rail. yeah people go on about crossover distortion, but you only really get that if you are working on a dual rail supply with AC. also current flows OUT of the input in those op amps, something to take into consideration in certain circuits.

>>2543125
i don't think you know what voltage drop means.

>>2543163
>i don't think you know what voltage drop means.
Please explain it to me then.

https://www.calculator.net/voltage-drop-calculator.html?necmaterial=copper&necwiresize=6&necconduit=steel&necpf=0.85&material=copper&wiresize=52.96&resistance=1.2&resistanceunit=okm&voltage=12&phase=dc&noofconductor=1&distance=3&distanceunit=meters&amperes=3&x=56&y=25&ctype=size

>>2543165
that website is also mis-understanding the term.
voltage drop in electronics isn't the amount a voltage has gone down, it is the voltage that appears accross a conductor or circuit. you are talking about losses, due to resistance, there is a voltage drop accross some of those conductors but it doesn't mean what you think it means. lets say you are using that 16awg wire which you state has a 2% "voltage drop". the voltage drop accross that conductor is not only proportional to the length, but also the load connected, saying 2% means nothing without other parameters.
so lets imagine some other parameters;
load is 8ohms, wire is 2ohms. you end up with 80% of the voltage accross the load, if the supply voltage is 200 volts, the voltage drop of the wire is 20% so 40V, the load has a voltage drop of 160V.
Wouldn't surprise me if some institution or company started using a different definition, because the people who make new standards for electronics are totally fucking retarded.

>>2543173
I'm not an electronics guy and I don't understand why it's wrong to use it that way. I understand voltage drop to be what you would measure with e.g. a multimeter with a probe before and after a component in a live circuit. In this case I just treat both wires coming from the power supply, positive and negative as one for simplicity, but I would check the voltage drops of each wire individually and then add the voltage drops together to treat them as one.

This is how I manually calculated everything to see if I understand what I'm calculating is the same as these online calculators:

I make the assumption that the pump is running at its maximum rating, a 12V power supply with 3 amps flowing.
Assume I use 6 meters of 22 AWG copper wire, which has 54.7 ohms per km of wire (according to wiki), that is then 54.7/1000*6=0.3282 ohms for 6 meters of wire.
We know 3 amps must be flowing both through the wire and the pump, therefore the voltage drop accross the wire must be 3*0.3282=0.9846V and the voltage drop across the pump must be 11.0154V.

Therefore the voltage drop across the wire, for 22AWG and given the above parameters, in percent is 0.9846/12*100=8.205%.

>>2543218

all of this is correct. the other guy who uses ratio of wire resistance to load resistance is also correct, and is saying the same thing you are saying except calculating it by a different approach. You are both using KVL and or Ohm's law and both work here.

I have two pairs of speakers taken out of scrap TVs and I wanted to use them to make a nice phone dock, however my smartphone is not powerful enough so I guess I'll have to make a small battery powered amplifier. The Art of Electronics has a couple topologies, however there's no mention on how to properly size the whole circuit for a particular load (i.e. the combined power and impedance of all speakers). Can you point me towards a good resource for this project? Also how to make a proper box for the speakers so that the audio is not completely awful.

>>2543406
>however there's no mention on how to properly size the whole circuit for a particular load
That's almost one semester worth of linear electronics in a typical university course. First part of
>Bob Cordell - Designing audio power amplifiers
should give you basic knowledge to start designing traditional class AB amplifiers. There is also part dedicated to class D designs, as those would be more appropriate for battery powered applications. You can skip all of this by buying an audio amplifier IC and copy over design from datasheet.
>Also how to make a proper box for the speakers so that the audio is not completely awful.
That's another semester of acoustics. At minimum you need to learn about Thiele/Small parameters so you can measure your speakers and then punch in numbers in to some online box calculator.

>>2543465
>buy IC and copy
Or I could just buy a portable amp, or a BT speaker, but then I'd learn nothing and where's the fun in that?
>uni semesters worth of study
Amazing. Thank you anon! I'll get on with that book you mentioned.

What kind of solder that you've used produced the shiniest joints? I swear I had some leftover loose solder wire so I don't know the type but the joints came out super shiny but I used it all up. I know it doesn't matter but I do a lot of prototype soldering and I love my joints shiny. Or rather I hate dull joints. Those muddy whitish kinds. They look disgusting.

>>2543548
Kester 44 is numba wan. Lower temp on your iron too.

>>2543580
Do you mean flux? 44 Is a type of flux. I am asking about solder. There is Kester solder based on 44 but there are a million of different types and they are all Kester 44: 60/40 50/50, lead free, etc and different % of flux, too.

>>2543548
i find in general that leaded solder is shinier, so start there

>Kester
>4.5g
>$12
Yikes. It is the price range of pure gold. LOL. No thanks. I am an ali express customer. Give me 50g for $3.

What temps do you set on your iron? Eutectic solder melts at like 180 °C, but even 200 °C is too low a temperature that nothing ever heats up fast enough, but the higher you go the faster flux gets consumed...

>>2543623
I experimented with different temps, but typically about 700F for lead based solder. Unless I want to make a bridge between two holes on a perf board, then for the solder to flow I typically lower the temp to 450F briefly.

>>2543621
I stand corrected, that's a sample size, 1lb is about $30-40. Still expensive but not ridiculously expensive. The thing is I will never use up 1lb of solder. Well maybe in 50 years. My pace is 50g in 3 years.

>>2543609
Flux-core
60/40 for general purpose or 63/37 for delicate work. Gauge is personal preference.

>>2543636
>1lb is about $30-40

not really.
Kester 44 is not a type of solder, it's a family of solder.
diff characteristics fetch diff prices, from about $30 - $120.
but even the cheapest one is better than anything on Alibaby.

never buy cheap solder or a cheap circumcision: they're rip-offs.

>>2542924
Looking back at the schematics for the EN pin, I see that there is the RC delay R1/C2 and there is the button debouncer R7/D8. When placed in the circuit, C2 and C8 are in parallel. Wouldn't that make C8 redundant? Isn't the C2 cap enough?

Also, could you confirm (based on the hardware defect you mentioned) that all is needed to flash/reboot is a reset pin on EN and a pull down pin on IO0? ( keeping IO45/46 unconnected, they are automatically pulled low on boot internally). So is there anything more I need to add apart from the D+/D- to IO20/19, push button to low on EN/IO0 and a UBB port to connect the cable that directly ties to GND,D-/D+?

>>2543636
Buy name-brand chink solder. I got some Mechanic branded lead-free stuff with bismuth and it was really nice to work with. They have actual data sheets so you can see what alloy and flux they use.

>>2543666
Yeah those are redundant.

I think that’s all you need, but I don’t know the story with the boot pins. If you’re fabbing a PCB I’d include footprints for components you probably don’t need, like jumpers from boot pins to ground and VCC. KiCAD’s 3-way solder jumpers are nice for this. Follow the datasheet of the linear regulator as to what caps it wants.

FYI I’ve never programmed an ESP32 before.

>>2543091
NFPA 79 has an ampacity table based around not catching fire in the event of a breaker trip inside a non-ventilated enclosure.

>>2543701
*************THIS IS A 2 PART REPLY 1/2
I can't thank you enough for your help, but thank you once more.
>I think that’s all you need, but I don’t know the story with the boot pins.
From what I read since last time we spoke, I think I figured the bootstrap pins out. On reset (or boot up), the pins IO0,3,45,46 are read and sets some behavior of the ESP32

>The EN pin resets the board when pulled low. Fed through the R1,C2 RC circuit to add a delay upon initial power up to allow power line to stabilize.

>Upon reset, the IO45 is internally pulled low through a 45k resistor, and is responsible for setting VDD_SPI voltage (3.3v if pulled low or 1.8V if pulled high). This is not necessary for the wroom boards since the QSPI flash is included and there is a fuse that is permanently burned to set it to 3.3V (or 1.8V on some models). In this case, it's set to 3.3V through the permanent fuse and this IO port can be tied to whatever on boot and can be seen as just another IO pin

>Upon reset, the IO46 is internally pulled low through a 45k resistor, and is responsible for booting mode (SPI = run program, download = download new program). In the former case, IO46 can be either 0 or 1 (don't care bit) and in the latter, it must be 0. So pulling this pin low all the time will allow you to boot in whatever mode you want assuming the other pin (io0) is configured properly.

>>2543701
*************THIS IS A 2 PART REPLY 2/2
>Upon reset, the IO0 is internally pulled high through a 45k resistor, and is responsible for booting mode (1 = SPI = run program, 0 = download new program). So to put the esp32 in download mode, I must pull this pin low (through a button switch, or if there is a way to automatically do it when USB is present, then through a transistor, although that would require more circuitry and the only way I can think of doing this is with a transistor tied to +5V_USB_bus that shorts IO0 whenever USB is connected, however this would mean the chip will always go into download mode if USB is connected and cannot be powered off USB, which is something I want. So unless I come up with a more complicated method, I think push button are fine for now.

Now where I get a little bit confused is about IO3. This pin sets the JTAG signal selection, which are:
0: JTAG signal from on-chip JTAG pins
1: JTAG signal from USB Serial/JTAG controller
**There are also internal fuses that can be permanently burned to select a specific signal source and then the IO3 pin becomes a regular IO pin same as IO46 above.

So I assume if I want to connect a USB to IO19 (d-) and IO20 (d+) without any USB/UART brige, I have to select the right source, but I'm not sure which one to select after you pointed out the HW bug. I think I must pull IO3 to low but would you be able to confirm?

>>2543701
>>2543724
>>2543725
If everything is done right, I assume when I connect the USB cable, it powers the ESP32 on, after a few seconds, the RC circuit pulls EN high, and at that time (if the io0 push putton is not pressed) it starts running the program. If I want to download a new program, I would push IO0 switch low, then reset the board with the EN push button. Then once it goes into download mode, I can stop pressing IO0 push button. Then comes the glitch you were talking about. So after flashing the new program, it doesn't reset automatically, so I'll just have to push the EN pin again, correct?

>>2543725
Only the S2 appears to have that hardware bug, but I’d also read about the security issue mentioned in the same post. I think it meant you couldn’t use download mode with USB, only the internal JTAG hardware, but I haven’t looked into it to see what boot pins or IDE settings that implies.
I’d definitely want to have a solder jumper from IO3 to VCC and GND, that way it doesn’t really matter.

>>2543738
>Only the S2 appears to have that hardware bug
Are you sure? I read that thread and people are saying that it works fine on s2 and it's the s3 that has the bug.
>I’d definitely want to have a solder jumper from IO3 to VCC and GND, that way it doesn’t really matter.
Good idea, i'll try both and see which one works.
Thanks a lot, from now on I think i'll just have to get the prototype board and test things out.

>>2543173
raster lainscope?

>>2543749
Oh yeah it's the s3 with the bug. Do you have the S3 or the RISC-V C3?

For the s3 there's this document I was talking about:
>https://www.espressif.com/sites/default/files/advisory_downloads/AR2022-004%20Security%20Advisory%20for%20USB_OTG%20%26%20USB_Serial_JTAG%20Download%20Functions%20of%20ESP32-S3%20Series%20Products%20EN.pdf
With links to both
>Device Firmware Upgrade Through USB
and
>Uploading the Application via USB-Serial-JTAG
For the former, it says:
>For ESP32-S3 series chips manufactured before Date Code 2219 (19th week of 2022) and modules and development boards with the PW No. before PW-2022-06-XXXX, the EFUSE_DIS_USB_OTG_DOWNLOAD_MODE (BLK0 B19[7]2) bit of eFuse is set by default and cannot be modified.
>Therefore, the USB_OTG Download function is unavailable for these products.
Which I think is why the guys in that thread were having to use the USB JTAG thing. So check if that date-code applies to you. No clue if it applies to the ESP32-C3.

>>2543774
I haven't bought any yet, i'm still designing, but I'm planning on getting the S3 due to the peripherals, amount of pins and USB. Would what I explained work on the S3?

>>2543829
C3 would work, just it has that hardware bug where you have to manually press the reset button. Honestly I can’t see that as being much of a problem, aside from needing to have a reset button in the first place. Maybe some people want to have automatic firmware upgrading, which I guess could be handy.

which crimp is better?
left is 72F-250-32
right is 280919-4
if I got the left I would buy a klein tools crimper 1009
if I got the right I would buy a chinese crimper and it has replaceable attachments like this (this does not include the crimping tool as the 1009):
https://www.aliexpress.com/item/1005002982897456.html

>>2543862
The one on the right crimps around both the wire strands and the insulation, which is much better for strain relief. It also has a built-in latch for fitting inside spade connector blocks.

Can someone help me out on are these chinesium capacitors a scam? I'm trying to build an induction furnace and need to pull a lot of current, and I haven't been able to find another decent source
These are $12 each, and I'm planning on grabbing 9 for a 3uF array

>>2543878
1.5J in a volume of 95E-6 m^3, or 16000J/m^2. Polypropylene stores 6500J/m^3, so off by a factor of 2.4. I'm thinking it's still possible to be legit if you consider additions to the PP to increase its dielectric strength or permittivity.

You could consider making your own capacitors by buying sheets of a dielectric and layering them with aluminium foil, it's likely cheaper. If you pick a thermoset resin or molten thermoplastic you can make any thickness you want, though removing bubbles and ensuring the plates are set properly becomes a challenge. As an example, you could store your full amount of energy (13.5J) in about 1kg of white PLA, which costs only $30 or so, plus time. Each layer would be 0.09mm or so, you can probably print that out as a couple of layers.

>>2542740
>>2542870
Thanks for the responses lads. Seems like my only option is to get a better opamp.
Those low power amps look amazing. It's kinda sad that hobby store parts are still 358 tier

>>2543882
Thanks! I've been paying more attention to the rated RMS current, but good to know that 3kv DC isn't bullshit either.
I found a reference on a tesla coil forum, apparently the company itself is legit. https://highvoltageforum.net/index.php?topic=1310.msg9914;topicseen#new
/diy/ capacitors are definitely on my todo list but I'm trying to limit to one project at a time. But if I can get this induction furnace working, I can get the foil from recovered aluminum scrap, which would be cool.

>>2543892
>It's kinda sad that hobby store parts are still 358 tier
Agreed. They also often sell TL072s or equivalents, but low-power op-amps and RRIOs are less common. And the MOSFET selections are ass. At least op-amps are something general-purpose enough that you can stock up on a bunch from digi-key or wherever.
t. works in a hobby store

>>2543894
>I can get the foil from recovered aluminum scrap
I imagine getting such a thin foil would be pretty tough, you'd probably need to hot roll it.
Seems like a pretty high capacitance from what I see of induction heaters, and a pretty high voltage too. Are you switching mains voltage into a resonant primary side?

>>2543906
>Are you switching mains voltage into a resonant primary side?
That's the plan. Annoyingly I have no idea how to characterize the resonant circuit, so I'm just copying what other people have built. The work coil is "a few mH" but maybe it changes when you add metal, so I've got a circuit for controlling the drive frequency by the phase of the tank voltage. The tank capacitance is "whatever it takes so that you resonate at your target frequency" and "maybe 300A" so I anticipate adding or removing capacitors empirically. And even the target frequency is just enough for a "gentle stirring action"
So basically the numbers are all made up and nothing matters, throw 12 kW at a thing and it will heat up no matter what you do. As far as I can tell all the hobbyists just tinker until they get it right

>>2543865
>crimps around both the wire strands and the insulation, which is much better for strain relief.

on several occasions i've come upon cases where the copper wire breaks but the insulation remains crimped.
so, you tug on the wire, and it feels solid, but there's no electrical connection.
it's the kind of problem that's a nightmare to troubleshoot.
coz you're not expecting that.
now i never crimp the insulation, and my banging-head-on-the-wall days are mostly over.
so, yep, i leveled up in real life.

Is there a hobby radio altimeter modules which get you a cloud of points to the surface, not just one point like a laser measuring tape?

Hi /ohm/, /g/ here. I bought an old laptop from the early 90s and it takes seven C-type 1.2V battery cells connected in series to get 8.4V voltage total. The cell technology is specified as NiCd, but I don't think those are sold any more. The laptop also takes a 4-pin power supply with two different voltages: 12V and 9.5V. I have no idea which voltage goes on which pin and how many pluses and minuses there are (there is a chance I could find this out by disassembling the laptop, but I'm not very good with electronics so idk), and sourcing an original power supply for this model is pretty much impossible nowadays. Nevertheless, if I somehow happened to come into possession of a working charger, I would like to be able to charge the batteries inside the laptop and not have to use an external charger. My first thought was lithium-ion rechargeable batteries, but those don't seem to be sold in this form factor and voltage specification. The only stuff that matches the specification is nickel-metal hydrate batteries. I can get type Cs with 1.2V and they are rechargeable. The only problem is that I've read that NiMH batteries can only be used in place of NiCd batteries if they will not be charged inside the device. Different charging characteristics will make NiMh cells quickly deteriorate. At least that's what I've read, so I came here looking for confirmation and asking for better ideas if anyone has any. Going with NiMh would necessitate using an external charger, but chances of finding or making a working power supply for this thing are very slim as it is, so it's not a deal-breaker.

>>2543917
>Annoyingly I have no idea how to characterize the resonant circuit, so I'm just copying what other people have built. The work coil is "a few mH" but maybe it changes when you add metal
It does change, and then changes again as metal heats up and melts. I've also tried to see if there is a simplified mathematical model available for this, but only thing that even comes close to approximately working is FEM multi physics type simulation which by itself will waste more time than just trying to see what works in real world. There is also 700 page book on this
>Handbook of Induction Heating (libgen)
If you want to do math you would have to grind Maxwell's equations + Fourier's equation of heat transfer. For DIY project without a research group of PhDs there is no other way, but to just build and see if it works approach.

>>2544010
Best guess is the charger (9.5V) might be in the PSU instead of on the laptop motherboard, which gives you the option of converting to lithium provided you can fit them.

>>2544010
>I don't think those are sold any more

walmart and every other big store on the planet sells nicads and nimh's.
they work exactly the same but nimh's have double/triple the storage capacity.

>I've read that NiMH batteries can only be used in place of NiCd batteries if they will not be charged inside the device.
>Different charging characteristics will make NiMh cells quickly deteriorate.

this all wrong.
the only real diff is nihm's can be usually be charged faster without overheating.
you can substitute in both directions.

still, if you're concerned, get something like an Eco-Six charger where you can specify like 8 diff battery chemistries.

Hello Ohm. So I finally did it. Put together a design in kicad of a board ive seen online and made an attempt at etching it. Printer toner isnt in great condition and I think the paper gets to hot and melts a little to the board making it hard to remove and not damage the ink but despite the issues it actually came out not to bad. Perfectly functional for my needs.

>>2544120
Good job, Anon. You did well for your first time. Maybe you could wet the paper to remove it with less fuss.

When the "shortage" ends?

I'm staying in a run down freezing cold trailer right now. I heat my bedroom with an electric space heater. It works well and it keeps me really warm and comfortable all night. However the circuit breaker keeps tripping, I had to get into the trailers panel and reset the switch each time. Last week the breaker directly underneath the main power panel (outside the trailer separate from the indoor circuit panel) had to be reset instead, which I found interesting because that hasn't happened before yet. I got back last night and everything was dark and there was no power, all of the switches were on the on position and was able to be reset. This is really concerning me and I'm not sure what to try next. I tried unplugging everything inside and flipping the switches on and off several times but nothing worked. Not sure what to try next? What do?

>>2539950
Don't you run into latency issues when you run traces like that?

The secondary coil of a transformer can affect the apparent inductance of the primary, right? If so, is there such thing as an inductance-neutralizing circuit for high frequency circuits?

>>2544159
use a lower power heater

Wtf is this? A 6 1/2 bench DMM with a shit ton of features for $280? It sells for $1500+ on other sides. It is out of stock sure, but it says factory lead time is 2 weeks, does that mean I will get it? In 2 weeks? A 6.5 digit DMM for $280? Where is the catch? Is it a "pre-order" price? Is it possible that it will be out of stock forever for this price?

>>2544152
After depopulation is complete.
>>2544159
>run down freezing cold trailer
Did you smell burning plastic at any time? The heater is drawing more current than the trailer's wiring can sustain.
>>2544163
https://www.psdevwiki.com/ps3/Syscon_Hardware

>>2544189
Wait this is the same model on Amazon. $3k refurbished. WTF is this. Should I buy 10 of them on Mouse for $280 and then sell them on Amazon for 3k?

>>2544159
If it works on another outlet then you probably need to replace the breaker.

>>2544189
Ah never mind, it's just a 3-year protection plan. LOL. Whew.

>>2544149
I did that and it comes off in layers but the final one is a but tougher to get off. Still comes off with the rub of a finger but it can damage the ink sometimes. Need to test more to see what I can do to improve it. But I need to address issues with my printer first.

>>2544196
>2 weak lead time for "protection" plan
Keithley family will take care of you. Now let's take care of those business expenses. We wouldn't want anything to happen to your measurements now, would we?

>>2544201
Did you press it with a clothes iron or run it through a laminator before trying to remove the paper?

please help me identify those things inside the green lines, I don't know what they are.

>>2544315
The black ones with numbers on them are surface mounted resistors. The other one is a ceramic capacitor.

>>2544315
5900 = 590 Ohms
473 = 47k Ohms
224 = 220k Ohms

>>2544317
>>2544320
thanks

>>2544315
Ceramic cap will be tough to reverse engineer. If it's just an 0603 bypass cap then a ~100nF should be fine (looks a tad too small to be 1µF), but if it's doing some analogue use then who knows.

FUCK DELAMINATIONS

>>2544369
wouldnt have that problem if you just ordered from the chinks

>>2544396
wouldn't have that problem if i could get a laser cutter working either. don't have enough board designs done yet to order a batch from jlc, ultimately i plan on getting a bunch of general-purpose boards from jlc (e.g. half-bridges, adc modules, dac modules, power supply modules, etc.) and more quickly etching my own boards that those more complicated boards solder atop of. theoretical turnaround is just a few hours of work per board, which for one-offs that i may want to quickly iterate on, is worth it for me.

Has anyone tried ordering parts thru octopart? It generate a list of some sketchy resellers or something, that I've never heard about, like NecroTrash or something like that, and you fill out a form and give your email and then what? Are they going to reply or just sell your email to the spammers?

>ATL431—2.5-V low-IQ adjustable precision shunt regulator
Wtf why is it low-IQ? I have some of those.

>>2544412
I think they're owned by Altium? So extrapolate their incentives from there. The main reason you're seeing obscure sellers is because the chip shortage has made them out of stock on the more mainstream sites.

What software can someone recommend for antenna design?
I am mainly trying to design an antenna for NFC readers.

lads
getting back into electronics after a 7-year hiatus.
designing an all-analogue (opamps+mosfets) blinkylights panel for my toddler with lots of dials and switches because she loves playing with those.
bought myself a used hp 34401a to "celebrate." (I always wanted a nice precision bench meter, and what better justification than building a toy for my kid?)
God I missed doing this stuff. Life is good. I hope everyone is well.

I need a panel mount connector for 15V AC, can't use a 2.1mm because I don't want the supply getting plugged into something that expects DC.
Are these the only option? I need only two pins that are insulated.

>>2544340
it's a motor for adjustment of the level of headlights in my car. So far, I've found a 220k (224) resistor shows 70k when measured, is it enough to make the circuit stop working?

>>2544120
Remember you can always touch up bad prints with a marker. I would have used a marker on these spots, but other than that it looks decent and usable.

>>2544468
Have fun anon. Good idea to teach your toddler about thermal runaway the hard way.

>>2544471
>can't use a 2.1mm because I don't want the supply getting plugged into something that expects DC
I guess 3.5mm jacks are also out of the question? Using a mini-DIN plug or just some other more obscure size of DC jack is an option, maybe pick an intrinsically non-polarised plug since polarity doesn't matter. Honestly those microphone plugs, while bulky, are great for having solid connections and strain relief.

>>2544473
>I've found a 220k (224) resistor shows 70k when measured
Could be in parallel with something else. The number of resistors makes me think it's something like a resistor ladder. I can try retracing it if you want. Can you get a part name or other writing off that 8-pin package? Knowing what goes on which of those five pins, and seeing the rotary switch contacts could be handy in reverse engineering. I implore you to try to trace out the circuit yourself, though I may give it a try in a day or so.

>>2544488
>marker
Not him, but I find those markers don't work for shit. Fade after a few minutes of etching. I paint on UV-cure soldermask (>>2544369).

>>2544473
>>2544492
ehh, can't see the whole board
i think the large purple one is ground
also what the hell are all these testpoints

Is it possible to modify an induction cooktop to use a sensor to hold a pan at a certain set temperature? Anyone know of anyone that's done such a thing or ideas about such things?

>>2544504
You can use a simple on/off control scheme or directly control resonant circuit with pulse skipping and PID. But why would you even do this? For low temperature cooking you already have sous vide tech, sauces and anything containing enough water caps at 100˚C due to water phase change and cooking at higher temperatures is just a matter of skill. The main problem is where do you put the sensor, because depending on kind of cookware you use readings will be different and won't match what actually happens in the pan. Pros all use mostly gas stoves anyways.

>>2544510
Well such a product already exists made by Breville/Polyscience the control freak it's called. It has a temperature sensor through the glass and I believe you have to use custom settings for each pan and an external probe you can use. It's really expensive though, and I thought it could be done more cheaply.

>>2544504
Probably. Chances are the signal path is
> buttons > MCU > power electronics
Not sure how easy it would be to pulse-skip on a resonant circuit, I'd probably try to either give false button commands (intrinsic delay), or replace/reprogram the MCU.

>>2544510
>not putting a thermocouple in your stir-fry
ngmi

>>2544512
I think the best way would be inserting thermal sensors inside the bases of pans and such, with a plug from the handle to the hob. Wireless might be too much work and a nightmare with induction magnetic fields floating about, but you'd have no shortage of energy to harvest via thermopile. I'd also really like to see pot lids that measure steam flow, so you can set a pot to a steady boil regardless of air pressure or pan type. Would probably use a variable-area flow-meter.

>>2544516
>I think the best way would be inserting thermal sensors inside the bases of pans and such
Don't give them any ideas. Last thing we need are DRM pans and various IoT sensors connected to blockchain smart contracts which determine what and for how long you can cook.
>your cooking smart contract has determined you have exceeded standard recipe energy consumption for this dish
>$22 has been deducted from your balance to cover cost of carbon offset credits
>social credit has been reduced by 3 points
>your right to purchase bug protein meat replacement products has been revoked
>please supplement your diet with plant based meat replacement instead now available as weekly service with our amazon smart diet affiliates
>have a nice day

>>2544516
Actually there probably is some way of intercepting the signal inside the power electronics like pulse-skipping, since there's got to be some method of power modulation. Or maybe it's something more sophisticated like FOC. Don't really know if FOC applies, but basically reading the magnetic field in order to change the phase at which you apply a sinusoidal current. Different phase angles would mean more load current and hence more output power. Just PWMing the pulses or changing the pulse lengths also works I guess.

>>2544519
I'm on /diy/ to avoid that future. Can't effectively ban something if I can make it out of billet. Would probably need to EDM drill such a long thin hole into the side of an existing frying pan. EDM is truly the chad technique for home-gamers. Don't need a rigid machine, just a lightweight but waterproof CNC frame, HV PSU, high-pressure, and a lot more time.

How come surface mount capacitors aren't labeled? What's the point?

>>2544492
>>2544494
>Can you get a part name or other writing off that 8-pin

it's a 0372dp1. the datasheet comes with pic related. I'll try to retrace the circuit later, no idea what those testpoints are.
>blue cap is 47 microfarads.

>>2544488
I botched this board because I didnt the bright drill bits. I remadanother using what I learned it came out a whole hell of a lot better had to use a markein a few places but well look.

>>2544552
I think (but am not certain) it's cheaper to simply do nothing, and the pick&place machines don't care if there's no label

I was looking for a thermocouple to use to measure temperatures. I am pretty dumb but they all seem to be several hundred dollars, are there any that are cheap? I was trying to make a program to log temperatures of various things so I wanted a bunch.

>>2544904
You may have found some high end stuff. Basic thermocouples are dirt cheap and pretty damn accurate. Just search for thermocouple on ali. You need a "K" type which is the most popular type. And a "K" amplifier. They are often sold together like this set. It is $2 on Ali.

>>2544938
That’s not an amplifier, rather it’s a full amp+ADC+cold-side-compensation digital IC.

>>2545040
Let's face it, if you just use an op amp and an ADC with a thermocouple you're gonna have a bad time.

>>2545123
That's the impression I get, but the ESP32 has dedicated low-noise ADC inputs for a thermocouple, so it can't be that bad. I bet a decent instrumentation amplifier using CMOS op-amps would work more than well enough.

>>2543125 (me)
I've installed the pump and it's working well. If I run it for about 10 minutes the wires do get warm, but it actually only needs to run for about 30 seconds at a time and sometimes maybe 2 minutes. The worst case is about 10 minutes, so it'll be fine.

If anyone was wondering what it was for, it was for an automated system to make carbonated water. The membrane pump creates around 4.5-5.5 bar pressure from my mains water supply (2 bar) and forces filtered water into a keg with a float valve which also has a CO2 flask with a pressure reducer attached to it which is at 4 bar.

It works well and I now have continuous cooled carbonated water on tap coming out of my diy modified fridge.

>>2545203
That's really cool anon. Got any safety features? Like a water leak detector, thermal sensor, gas leak sensor, etc. Are you using gas from a welding cylinder, or something like a sodastream cylinder?

>>2545230
I thought about all that but realistically there's not much that can go wrong. I store syrups inside the fridge so whenever I open it I can see and hear if something is wrong and you can't overhear the pump because it's loud. The fridge has a hole at the back for condensation to escape. In case the fridge does flood and the door isn't forced open, that's where the water would escape and it would be very visible on the kitchen floor. The mains power supply is on a different shelf above and next to the fridge, so that water can't get anywhere near it, that's why I used a 3 meter long cable which feeds into the fridge.

Worst case the fridge gets flooded and with it the kitchen, but even so, relatively slowly because the filter (on top of the fridge, might mount on wall) and the 1/4 inch water pipe both already limit the water flow considerably. For the water connection I used the same 1/4 inch pipes and plug fittings that are used for those samsung fridges and we've been using those for at least 8 years and they're extremely reliable, never had any issues with this style of fittings. The small pump is hanging from the ceiling inside the fridge to reduce noise and also prevent water getting to it from the outside in case of a leak.
>Are you using gas from a welding cylinder, or something like a sodastream cylinder?
I use a 2kg CO2 flask, sodastream is overpriced. I don't worry about gas leaks because these don't contain enough CO2 to pose a threat and the kitchen is open + we air regularly. I also intend to fully check the system every half a year or so.

I'm going to add a 4-5 ampere inline fuse and a 77C thermal fuse which I will wrap with the wire, it's quite cheap and trivial to add and would be a good safety addition I think.

>>2541876
This is the effect people get when they jumper the 4 input Marshalls. On the left two channels are in parallel. Intuitively most of their overdrive is from abusing subsequent stages like the phase splitter and you've given them double the current available. Having 500k to ground on the right will attenuate some volume. You have a mild eq with that configuration.
High gain amps use several stages with controlled attenuation and bass or treble cuts. They also choose which sides of the signal to clip. If you were to series your stages instead, it becomes apparent why everything must be more tailored to your goals.

>>2543636
I finally used up my old radio shack roll of lead solder and now I'm on a kester roll. The hot flux vapor just doesn't smell the same.
>SNIFFFFFFF

This guy did a self reflowed board https://youtu.be/r0csHZveVvY
toms hardware made an article of it.
https://www.tomshardware.com/news/this-pcb-solders-itself-then-others
I think it is a really interesting concept for a board, being able to reflow a pcb with any kind of oven or soldering station, would be perfect for beginners kits

>>2545334
>would be perfect for beginners kits
>$157
For that kind of money you can get either a hot plate or combo soldering/hot air station. Or just mod a $60 convection oven. Those gimmick projects are good just for generating clicks on youtube.
>convection oven soldering :|
>self soldering PCB :O

>>2545337
I mean as an idea design, not the one he is selling.

>>2545345
It's just a waste of perfectly good (and expensive) layers. And breaking ground plane will have horrible consequences for EMC because broken return paths will scatter fields everywhere. It's just a horrible idea from engineering point of view.

>>2545169
what's the point, just for the heck of it? if you have a cheap ready made solution with SPI. if you want to roll your own, you also need some kind of a compensation for cold junction. look at a simplified diagram of MAX6675. it is not as simple as it sounds if you want any kind of accuracy.

>>2545349
It's a cute idea and it worked, perfect for jewtube, terrible for reality.

Is touching low voltage and extremely high amps really harmless? Like 3V 500A.

>>2545442
Maybe, maybe not. What if there is a catastrophic failure upstream and you get 500V 3A?
>Here lies Charcoal Chuck. Killed by a chink spot welder sold through Harbor Freight. He saved a buck. He's Charcoal Chuck. RIP.

>>2545442
Yes, because body impedance is just too high. That 3V just won't be able to push any significant current.

>>2545442
yes extremely harmless. 500A is not through you but through the circuit. unless you are made of metal

What's the most reliable and cheapest way of building a inverter 12V to 230V that can withstand a load of max 4kW?

I need a 5k pot but I only have a 1Meg pot. Is it possible to linearly convert 1Meg to 5k, i.e 1Meg goes from 1Meg to zero while the output goes from 5k to zero, on the entire range through some elaborate serial-parallel bank of constant value resistors?

>>2545455
Found something called "generalized impedance converter". Can I achieve the same result without any active elements? Just linearly convert two resistances, a much narrower task.

>>2545455
>>2545463
No, I don't think it's possible with only passive components. Most basic way would be to put pot parallel with 5k. When pot is at 1M parallel combination is approx. 5k, when pot it's at 0 is at 0. But the catch is it won't be linear at all and small range of movement will cause large changes. Just buy a 5k pot.

>>2545299
Fair enough, looks like you've put a lot of thought into it. I hope the filtered tap water is sufficiently good tasting for you, I guess if you're putting syrups in it then it doesn't really matter.

>>2545355
For more than 12 bits of resolution, and to perform your own oversampling and DSP. Also considering the 6675 is $16-25 from reputable sources, I have serious doubts as to the quality of the chink ones. Then again, LCSC has it for $1.50. What the fuck?

>>2545452
A ZVS circuit tuned to approximately 50Hz. May want to add high-current gate drive ICs to cut back any remnant switching losses. You'll still need some really beefy transistors and a big transformer. Run some simulations to see what the required power ratings are, and what the turns ratio needs to be. With any luck you can just buy or salvage the desired transformer.

>>2545455
Why do you need a 5k pot in the first place? Post a circuit, maybe replacing other passives will allow a 1M pot.

>>2545559
>A ZVS circuit tuned to approximately 50Hz.
Is there anything more oldschool with thyristors for example

>>2545568
I think it's possible to make a resonant power converter using thyristors. I say resonant because they can be a lot more compact, even though you get less control over voltage and frequency output.

>>2545559
>Why do you need a 5k pot in the first place?
LM317 voltage regulator. 300ohm + 5k is what I need to regulate from 1.25 to about 20.

this: >>2545463 seems to work in simulation but i am thinking it is too much trouble.

>>2545559
>6675 is $16-25 from reputable sources
yikes that's a rip off. it is worth $1.50. it works fine. MAX31855 is a better chip, it is 14 bit and it costs $2 on LCSC.

>>2545601
Why not 30kΩ + 500kΩ? Or is quiescent current into the adj-pin too high for that? You can buffer the output of the voltage divider with a single op-amp.

>>2545606
>MAX31855
Only $7 from western distributors. Huh.

>>2545626
The quiescent current is on the order of 50-100uA and is unaffected by the choice of R values, but if R2 is too large it will drop too much voltage so it won't work since VOUT=1.25(1+R1R2)+IADJ*R2
usually the second part is ignored since it is considered close to zero if R2 is on the order of a 100-200 ohm.

>>2545638
>usually the second part is ignored since it is considered close to zero if R2 is on the order of a 100-200 ohm.
Yes but the entire point is you could use your 1M pot if R2 is on the order of 10-100k. Anyhow, I suggest doing pic related:

i have one of these chinkshit ultrasonic transducers. i want to build my own driver circuit with a bridge topology. will it harm the transducer if i run it without a load? or must it absolutely be coupled (mechanically bonded) to a load?

>>2545667

>>2545667
Should be fine to run when not connected, but I'd read the datasheet to be sure. IIRC those guys want to be driven to be resonant, so I'd make a feedback circuit to keep them at the ideal frequency regardless of how a mechanical load would cause it to shift. I've done that before using half-bridges, turning the capacitive load into the C of an LC lpf, but in this case you may want to use a seperate transducer for feedback. Or current monitoring via an MCU that can change the driving phase.

>>2545626
If you want to go full autist mode you could try using one of those 24-bit ADCs, for example ADS1220. It is cheap and it has a built-in 3ppm Vref.
or any similar delta sigma ADC with a built-in PGA and a temp sensor so you could also account for the cold junction and you probably won't need any other part since it also has an internal buffer so you could connect the thermocouple directly to the ADC. Would be interesting to compare the results with the maxim parts. I mean you could get at least 16 noise-free bits out of those ADCs, what else do you need.

>>2545673
thanks. im still shaky on understanding the concepts but i think im going to do it via MCU current monitoring like you suggested. probably a half bridge driving an impedance matched transformer. i've also seen people use ICs like cd4046 but i don't understand them very well...

Can i make relays that are active at low work as active at high by connecting to the normally closed instead of normally open?

>>2545677
>probably a half bridge driving an impedance matched transformer
You'll want a series inductor either way you go, because the sudden current spikes from the half-bridge will saturate your transformer. Also consider a centre-tap primary with two low-side FETs instead.
>CD4046
They're fucking cool, man. But I'm not sure how they fit in here. Arguably you could swap phase comparators or use a variable-gain amplifier or voltage offset after a phase comparator in order to change the driving phase, which sounds cool.

>>2545681
Isn't that the entire point of having both NC and NO pins on a relay?

>>2545675
i've seen lots of autistic examples of people buffering the shit out of every adc component and using a much noisier opamp and reducing the resolution by a few bits. hell, i've seen voltage references being buffered. thermocouple is a very low resistance source and doesn't need to be buffered.

>>2545683
>Isn't that the entire point of having both NC and NO pins on a relay?

I guess it's one of the use cases.

>>2545559
>I hope the filtered tap water is sufficiently good tasting for you
I use the same filter in my fridge for plain water and it tastes very good. Even better than the bottled waters I've tasted.

trying to make a foam cutter out of an old hair dryer.
im using a 12V power supply, but the voltage across the element needs to be closer to like 5-6 volts. the element has a resistance of ~1.5 ohms. i tried putting some 10 ohm resistors (3 in parallel) in series, but they just exploded instead. what are my other options?

>>2545768
lol im retarded, just need to make the element twice as long.
senior year EE student btw

>>2545768
>>2545773
I'd consider PWMing it with an LC filter after to smooth out the ripple. Some call this a "buck converter", feedback optional. Also watch that you're not conflating cold resistance with hot resistance when running your calculations. Inrush current will always be higher than operational current.

Do LM334s come in different flavors with different Vref? According to the datasheet I=227uV/R. According to some other source it is more like like 70mV/R which what I see in Ltspice. But the part I have required a 330ohm resistor to get 6ma. So it is 2 volts??

>>2545838
thanks for advice fren, if i was making something more permanent would definitely do that, but this was more of a "need to cut some foam in my dorm room and then never again so macgyver something up in 2 hours" type of project.

>>2545864
nm i am ret

>>2545895
Can explain? Your question confused the shit out of me.

why would anyone use an lm334 in 2023 anyhow? looks like it's got terrible tolerance compared to even a tl431.

>>2545907
Two issues: I got the pinout wrong from a random picture on the web instead of the ds, so I swapped input and output. And that 227uV/C is the temco. The proper Vref is 68mV and that works fine.

>>2545915
tl431 works but needs more parts. lm334 just needs a resistor for low currents where accuracy is not critical, for example Imin for LM317. hey, dave used an lm334 for this exact purpose in his bench power supply build.

I need to add a D cell battery pack as a backup to a system with a 100Ah battery (lead acid for now, but battery chem could change). If I use a BMS on both power sources, can I safely wire these together for the same load? Or what's the not stupid way to do this?

An LCSC brand:
>Failong Crystal
Someone needs to tell them.

>>2546175
>Peng Cheng Hardware Plastic Products
>Jiangsu Changjing Electronics Technology Co., Ltd.
>Hsin Da Precision
>Bothhand Enterprise
>American Electrical Inc.
>A Power microelectronics
>Acam Messelectronic Gmbh
>3G Shielding Specialties LP

Im following an online course about PCB design for a product I want to build. The instructor said to work through The Art of Electronics as a prerequisite, if you're inexperienced with electronics (I am inexperienced). Is it reasonable for a noob to work through 10 pages a day of this book and be good to go in like ~2 months? I know it's mentioned in the sticky as the most difficult book

>>2546266
>Is it reasonable for a noob to work through 10 pages a day of this book
Yes.
>and be good to go in like ~2 months?
Not unless your IQ is over 9000 and you have unlimited funds, components, tools, and materials you need. Even then, you need experience which only comes with time and practice.

>>2546273
Sorry, I should have been more clear. I meant "will I be good to go to take this class about PCB design". More specifically, it's mixed signal PCB design, like guitar pedals

>>2546156
If you use diodes to prevent current from flowing back where it wouldn't belong then probably. But if you just use BMSs then if the D cell pack is a higher voltage, it could easily backflow into the lead-acid and drain itself. Even with diodes, whichever battery is a higher voltage will get drained by the load, so you'd have to set the maximum D cell voltage to be lower than the minimum lead-acid voltage. So instead of diodes, some power FETs or a contactor/relay of some sort to switch between the batteries (plus sufficient capacitance to make up for the jump) might be the way to go.

>>2546266
>>2546275
A lot of stuff in AoE will be superfluous to your end goal (e.g. power electronics, RF and transmission lines), but in general it would broaden your understanding of electronics anyhow. I recommend following along with AoE's labs too, but doing that all with a breadboard yourself may not be possible. There's always simulators if you need to get a bit of intuition as to how changing variables will affect a circuit.

>>2546275
You'll definitely have an advantage over someone who didn't prepare for the course. The most important thing to remember is that you must start at the beginning and learn the fundamentals. Otherwise you're going to be spending too much time working backwards.

>>2546280
ok, i'll look into the labs. I have some good breadboards and enough supplies to make blinkies but not much beyond that

>>2546266
AoE is a reference book, it's not the best thing for beginners because lots of details are omitted with hand-waving (the Art part in AoE). For PCB (general purpose, no RF) design main things you need are
>passive component basics (RLC)
>network analysis, basic theorems, KVL, KCL, thevenin, norton, combinations, transformations
>signals and systems, transfer functions, feedback
That alone would be quite a lot for 2 months. Think of it as basic analog language that allows you to understand circuits. Then you need to add
>physics of electricity
>semiconductors
>digital systems
>thermal design
>... other things depending on your needs
Unless you're Korean kid that studies 16h/day it's probably best just to focus on passive components and network analysis. 2 months is basically nothing. I've studied electronics for 5 years in university and I still feel like a retard.

>>2546306
>I still feel like a retard.
Dumbasses never think they're retarded. That means you're smarter than average, Anon. Non-retard.

>>2546310
But what if I'm actually retarded and just haven't realized that yet? This means I'm superretarded, because my retardation is in superposition as I haven't collapsed my retard wave function yet.

>>2546266
>AoE
overrated and useless for beginners. others already mentioned why. it is a mystery to me why this book is recommended to beginners all the time.

>>2546329
how about "i am smack in the middle of the downward slope on the dunning kruger". it is a good way to introduce yourself at parties and steal all the attention.

>>2546337
I already went through the first book in the sticky (Mims) so which of the other three besides AoE would you recommend next? Or perhaps something else entirely?
>Geier, How to Diagnose & Fix Everything Electronic
>Kybett & Boysen, All New Electronics Self-Teaching Guide
>Scherz & Monk, Practical Electronics for Inventors

>>2546337
>Horowitz
>it is a mystery
>don't forget to buy X chapters and lab book
Main book is just an advertisement for X chapters. I get so pissed when I start reading something, it gets interesting and then I get jewed by
>this is further discussed in 3x.4
I switched to
>Electronic Circuits Handbook for Design and Application
Authors are german and not afraid of math. Concept are short, precise and understandable. There is also no hidden chapter trickery.

Total beginner here who has only object in mind: to restore, maintain and fix music gear I own.

Are the resources in OP in Principles section relevant who really starts at zero knowledge? When it comes to electrics of the things...

My interest mainly in digitally controlled analog products; e.g. mostly they use vactrols for channel switching and other routing. Also circuits (log amp for the compressor, use of the LMC835 to implement the GK active EQ filters (in addition to the graphic EQ), noise reduction ckt, even an R/2R DAC). The thing is I really just have technical documentation, schematics on most of this stuff. I lack the knowledge to correctly diagnose what's wrong etc.

I guess I could be totally fine if I could just diagnose problems and see what components might be causing the trouble or are in need of replacement/maintenance without going super deep into the stuff. I stay away from all high voltage stuff and power amps.. most of this stuff is probably very low voltage...

Is there something "unfixable" or point of no return when it comes to consumer gear from 80s, 90s? Are there come components that simply are not made anymore and you literally cannot replace it and it just becomes unfixable some point or is there always some workaround if you have the understanding, schematics of the thing at hand etc.? These are my "concerns".

>>2546306
>lots of details are omitted with hand-waving (the Art part in AoE)
Pretty funny.

>>2546346
>Scherz & Monk, Practical Electronics for Inventors
This one. And also some college books on circuit analysis. For example:
Alexander, Sadiku - Fundamentals of Electric Circuits (Part 1 and a few chapters from Part 2)

There are many similar: Boylerstad or Irwin or Miller. Pick ONE that you like the best. They are all roughly the same.
And the second group of books are Electronic Devices. Again, pick one of these:
Boylerstad or Floyd or Sedra/Smith.
They all cover solid state

What's the deal with all the different voltages for three phase stuff?

There's a three phase panel at this place with three different circuits, all 50 amp double poles. Can I run this thing at such a place? Manual: https://catalog.electrosteam.com/Asset/LG---USER-MANUAL-New.pdf (see 'schematics and wiring' section)

>>2546517
The model I'm looking at is the 25kw. I don't wanna have to buy a 60A extension chord so I'm trying to figure this all out.

I need something a bit odd. I need a surface level switch for toggling between two circuits (a or b active) but i need it to be remote (as in by wire) without increasing latency within the circuit. Wtf can i use?

>>2546580
what kind of latency levels are we talking about? how much current and voltage are you switching? what do you mean by "surface level"?

I got a cracked flatscreen, I could replace the screen, but I don't need another TV. I was wondering however if these things have any parts inside that could be repurposed for use elsewhere. Like in electronics projects or maybe there's programmable micro controller inside. If you got any ideas I'm all ears.

>>2546595
light table

>>2546584
>>2546584
10 micro seconds
3.3 v
Just a switch, but not far

>>2546598
I thought about that, but I don't have use for one of them. Do light tables have any use outside of drawing animations?

>>2546595
>>2546604
Laying out circuits the old fashioned way.

>>2546602
Pretty sure any normal FET or BJT as a switch will handle that without problem. Though to switch a high current, you'll need a higher power transistor, which take more to turn on. So again, how much current are you switching?
>Just a switch, but not far
Are these words meant to mean something?

>>2546617
>Laying out circuits the old fashioned way.
man I would love to design and fab my own ICs.

>>2546634
Why not do it?

>>2546634
I think they also used light tables for PCB layout, IIRC there's a youtube video on the topic about designing the boards of old Techtronix oscilloscopes.

>>2546638
I don't own a fab. There's probably a site somewhere that'll fab designs I make, but I want to do that myself.

>>2546645
http://sam.zeloof.xyz/category/semiconductor/

>>2546617
Sorry, its like 50cm from the device.

>>2546701
how much current

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>>2546736
7.5A