/ohm/ - electronics general: The best of times edition

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Hey, I have a question about the Cockcroft-Walton multiplier. I understand it fully how it works with an AC input, but apparently it also works with pulsing DC voltage, at least Wikipedia says that. So what I want to ask is, would it really work, and if it would, how is that even possible? Does the circuit need alterations, from say, pic related? Or is the circuit actually clamping down the voltage to -1/2Vin because capacitive coupling?

>>1183379
The very first capacitor removes any DC offset in any case. It does not matter whether your input waveform's peak values are, say, +100V/-100V or +200V/0V.

>>1183379
You can test it in Spice. The actual reference voltage doesn't matter since you set one side of the sinusoid to be ground. The higher the frequency the more efficient the circuit, but be sure you don't enter a frequency too fast for your diodes to work. I wouldn't try to draw any more current than a 1kΩ across a 4-stage multiplier running off 1MHz 50V, if that's a useful ballpark.

>>1183394
>>1183503
I see, thanks.

Why is the Pololu VNH5019 dual shield better than the L298N dual-H? Assuming I want to drive two standard 12V DC motors from a 12V battery, would there be any fundamental difference in performance between the two? They're both rated to perform above what that would require, but the Pololu is five times as expensive.

>>1183585
for a 3 amp motor the VNH would dissipate a quarter watt while the L298 would dissipate a few watts. that will be the only difference. also i would expect the L298 to have worse switching losses than the VNH for pwm but check the datasheet.

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Question: Can I use a voltage doubler to power some vacuum fluorescent tubes instead of a boost converter (e.g 2577)?
Which is more efficient at very small loads like the ones required to drive a vacuum fluorescent display?

>>1183669

a proper boost converter will beat the pants off of a voltage doubler 99 times out of 100. voltage doublers/triplers/etc are only good for a couple of mA before the voltage drops precipitously.

After about a decade or so one of my IPS monitors backlight is starting to flicker. I have little to no idea about electronics and guessed that this might be due to capacitors dying. Is that a reasonable assumption?

>>1183689
same guy, ironically the monitor died about 10 minutes after writing this post. It will only show an image for ~1 second when it gets a new input/turned on, then the backlight craps out.

What might be the cause for that, and is it fixable?

>>1183703

a 10-yo monitor almost certainly uses fluorescent tubes, and those tubes have a limited lifetime before they sputter out, or start drawing too much current and are shut down by the power supply.

alternately, the high-voltage supplies that feed the tubes can die (or get very sick).

if you like to live dangerously, it's possible to determine which is which by connecting the high voltage wires to some external tubes pulled from another monitor.

a safer idea is to get to a thrift store where 17 and 19-inch monitors abound for under $10.

>>1183717
does that match the problem of the screen working fine for a second or so until the backlight craps out? If that's the case i'll just toss it out i guess

>>1183722

yes it does. electronic components are like people, they dont just keel over suddenly, they often act screwy beforehand.

>>1183725
allright, thanks for the help

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when you use two 120v legs to make 240v (as in using 2 extension cables coming from 2 sockets out of phase) do both entire legs now experience 240v or only at the device youre jerry rigging?

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>>1183679
>only good for a couple of mA
That's exactly the load I'm expecting to get drawn by VFD's. I'll do some tests to determine which way is more efficient.

>>1183825

only the ''thing'' gets 240V. the other sockets use the neutral which means they always stay at 120V.

Question:
How long will an LED light that draws 8 watts last if powered by a typical car battery if the light is the only thing drawing power?
I mean how long will the battery last before being drained.

I read a good car battery might reliably give 80 amp hours at 12 volts which is 960 watt hours??? So if the light draws 8 watts it will last 120 hours. That sounds about what I was expecting but did I figure this right?

>>1183844
Thanks
Thought that was the case but I just wanted to make certain before I started blowing shit up

>>1183835
Even then, you need to put a bit of effort in it to beat a decent boost converter. For example, the schematic you posted isn't even trying to be efficient.
But why do you even care? VFDs aren't exactly the go-to display if you want low power consumption.

>>1183850
Yeah, the logic is correct, but if you suck a car battery totally dry, it won't last many cycles.

>>1183585
>>1183597
The L298 will also lose about two volts. So if you're using a twelve volt battery, only ten volts will actually go out to the motors. I'm not aware of the SNH having that problem.

i got an esd mat whose grounding strip ends in a ring terminal.

i don't have any ring terminals or fasteners on me so my solution was to slide the ring over the ground pin on a spare mains plug and then wrap some wire around it to get decent contact, and plugged that in. is there a better way to nigger rig this? there's continuity but if the wire decides to unwind itself in the wrong direction it'll short.

>>1183954

- find an old 3-wire cable
- remove and isolate live and neutral
- strip 3/4-inch from ground wire
- make a sandwich from the curled up ground wire and 2 washers
- hold it all together with a nut and bolt

>>1183825
Wouldn't that only work at 180° out of phase? I thought house phases were all 120° out from each other, and two-phase just used two of the three phases. I could be wrong though.

>>1184002
no, house power is 1 phase 2 pole. each slot in the panel is 180* out of phase with its top and bottom neighbor (0, 180, 0, 180, etc) which is why you use a double breaker for 240v appliances. so if you run 2 extensions from 2 legs that are out of phase, you will get 240v from both hots (rather than 120v from hot and neutral). 240v appliances like dryers use 2 pole setups with only 2 hots for the heater or whatever and the neutral is just to power any 120v electronics that may be in it

>>1184002
In North America using split single phase for residential use is common so that high power things like ovens/air conditioning/hot water etc can run off 240v while everything else stays 120, getting three phase service is more rare than the rest of the world.

>>1184073
>>1184085
That makes sense. Apart from the obvious electrocution risk and wire gauge/insulation differences, what are other advantages and disadvantages of having 120V over 240V?

>>1184109
Not that I can think of. Most reason is because it's considered safer Because usually if you grab 120 (like say you grab a metal pipe that has a hot touching it) you'll be able to let go in a second, but if you grab 240 it tends to make you contract and hold it, making it harder if not impossible to let go. Plus 1/2 the voltage means 1/2 the current going through your body making it that much harder to kill you.

>>1184109
IIRC 120V was more convenient voltage for ye olde filament lamps.

>>1184132
Yeah, that's what I thought. I guess you'd need smaller step-up transformers for microwave ovens and such with 240V, though the 50Hz would require bigger cores. Of course the inverse is true with needing smaller step-down transformers with 120V mains. I wonder when we'll get microwaves running off step-up converters with really beefy FETs instead of transformers?

Also capacitors are only slightly less space and weight efficient than flywheels for energy storage. For capacitors, diamond has the highest energy density at 177MJ/m^3 while for flywheels, maraging steel has the highest energy density at 654MJ/m^3, twice that of a lead-acid battery. Diamond still has the highest energy/mass capacity at 50.3kJ/kg, while carbon fibre reinforced polymer has the highest energy/mass capacity of other flywheel materials at 150kJ/kg, which is about that of a lead-acid battery. This is all absolute maximum ratings, from the dielectric's breakdown voltage and the flywheel material's tensile strength, so I'd expect to store a little less. Petrol and even Li-Ions are well above all these too.

The more you know.

So i pulled two (i assume) dead batteries out of an old UPS that have been sitting idle for a couple of years.

They both put out around around 1.5V and are rated 12V / 17Ah.

Anything i can do to get these back to live?
Refilling with distilled water and normal charging doesn't cut it anymore.

>>1184262
Nope. Drop them off for recycling wherever.

if i want to design a monopole pcb antenna and don't have access to a VNA, are there any reasonably simple simulators that can take my ground plane into consideration to give me which matching components i need?

>>1184397
Just use Maxwell's equations and figure it out from there, you'll be fine.

>>1184429
i went ahead and wrote my own FEA suite instead, but thanks.

hey /ohm/, I'm not use to doing these kinds of things so bear with me please. I'm trying to fix my television the volume keeps going up so I took it apart and check the volume control board and I disconnected it and it did not stop problem then I disconnected the infrared receiver board and that did not stop the problem either so my only guess is that there's something wrong with the TV deeper inside of it.

>>1184433
if the volume button board doesn't have a serializing chip on it then it's possible that the pcb trace for the volume button is connected to a voltage rail somewhere, maybe by dust. clean the main board.

>>1184439
I took a look at the main board. It surprisingly clean. Maybe it's a leaky capacitor?

>>1184451
can you change the volume yourself at all? if not maybe it's a cracked trace or pad leaving the volume trace floating, and then getting pulled high by leakage.

>>1184455
I can change it by pressing buttons on the volume board but it still continues to go up.

>>1184459
well there's no reason to suspect a bad cap for that problem but it won't hurt to check if you know what to look for.

>>1184463
I checked all the caps none of them are leaking or bulging. I'm out of ideas. Do you have any?

>>1184468
you say you can change it by pressing the buttons, but does the remote work? if not that would answer your question but it would be a really weird fault.

>>1184470
The remote doesn't work, guess I'll just salvage what I can and throw away the rest. Thanks for trying.

>>1184485
it would make very little sense but you should still try to trace out the data line from the IR receiver to wherever it goes. hairline cracks can be difficult to spot.

>>1184485
Could the "dead" remote be sitting close enough to the TV to be sending faulty "volume up" signal constantly? That might be happening if the button or something in the remote has gone short circuit.

>>1184490
I can't any cracks on it

>>1184502
I've removed the batteries and put the remote in another room. I don't think the remote is the cause.

>>1184511
Just checking. My folks actually have a TV like this back home, but worse than just the volume, it changes contrast and brightness, along with another myriad of unused features. In that case I'm pretty sure it was a faulty control circuit, because using the volume buttons on the side didn't work either. I can't see any reason why the silicons would break in either of our cases, so I suspect it's the traces or passives, both of which you checked. Unless the "planned obsolescence conspiracy Jew" has paid you a visit, I can't think of what the problem would be.

How safe is it to buy IC's and transistors off of Aliexpress? I want to buy some LM317s and IRF510 transistors.

>>1184549
perfectly safe 鬼佬

>>1184549
very safe

the only ICs from Ali I ever received that were kinda fishy were some AVRs

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>>1184549
The simpler the safer. A BJTs, opamps, 3-terminal regulators, diodes, fine. FETs and capacitors and ADCs, probably fine, but don't run them at max stats. Anything high voltage, just don't use it for high voltage. Screwdrivers? Definitely not.

>>1184549
I buy ICs from aliexpress all the time, as long as the seller has a good reputation and you don't look for ultra rare, out of production ICs you should be fine. As always, if it's too good to be true then it probably is, chinks copy everything, even ICs, if you find what you're looking for 10x cheaper you might be buying a knock off.
>>1184552
I just bought some smd Attiny85 and 2313, I haven't tested them but they seem ok.

What happens if you run a 110v-12v transformer off 240V? Will it still output 12V but run hotter or will it output some other amount of volts?

>>1184700
It will output 24v for a moment then nothing because it burned out the primary.

>>1184700
transformer cores have a maximum flux density (amp-turns divided by core cross sectional area) at which they enter saturation. this results in them temporarily losing their magnetic coupling and their primary inductance dropping. that means you'll get clipped waveforms and heat. if it overheats and doesn't have a thermal fuse then the wire enamel can start melting and who knows what will short or break.

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How do I buy the right replacement Li-Po battery without a spec sheet?. Anything to look out for other than voltage, amp-hours, and dimensions? I've been seeing things like low-current shutoff and charging voltage that I'm not sure about.

Pic is the current (fried?) battery. It smells like acetone and the device (GPS watch) doesn't hold a charge.

>>1184847

maybe you should get a 3.7 volt 300 mAh

>>1184884
Yep, I know 3.7V/300mAh and the dimensions. Does the charging circuitry differ at all?

>>1184890
charging voltage only varies with chemistry, so any lipo will do. internal battery circuitry is almost exclusively for safety and won't impact its operation unless there's some gimmicks out there i'm not aware of.

>>1184929
Great, thanks!

>>1184933
RIP house
RIP anon

>have small engine with charging stator
>has a rectifier+regulator unit
>20-30vac directly from the coil (2 pin plug, not block grounded), nothing from regulator
>order new regulator
>Same story
Any way to diagnose this?

Good idea to encapsulate finicky soldier joints in hot melt glue? I have some projects using a microcontroller, rotary encoders etc.. and I'm constantly afraid shit's gonna break. I found this company which sells glue sticks specially for potting electronics, should I go with that or will regular hot melt work just as well, besides the longer setting time?
https://www.hotmelt.com/products/7718-knot-filling-glue-10-stick-packs

>>1185220
I'd personally go with Silastic.

>>1185227
good tip, thanks

>>1184433
Try cutting the main wire of the flyback transformer while the TV is still plugges. Btw the handle of the knife has to be conductive

>>1184140
Transformer size doesn't change with 120 vs 240V , for the same output and power strength going from a 120 to a 240V desogn you need twice the wire length to get double the turns, but can be half the cross sectional area, so no change in total volume/mass of copper.

Magnetrons and big ass transformers in microwaves aren't going away any time soon, doing hogh power RF with semiconductors is still a lot more expensive.

This look like it's worth cleaning up and fixing? It's a Micronta 22-203A and I probably already have all the tools and parts.

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>>1185283
Forgot the pic.

>>1185283
Do you like it? Do you think fixing things is fun? If yes, then maybe.

If not: it's an unimpressive broken old multimeter. You can get a similar working one for $10.

>>1184109
120V gives a better efficiency/lifespan trade-off for filament lamps.

R=V^2/W. At 240V, for the same power you need 4x the resistance. Which means that you need to either
a) make the filament longer, which increases the surface area, decreases the power/surface-area ratio, lowers the temperature and so lowers luminous efficacy (Lm/W), or
b) make the filament thinner, which decreases the surface area but also decreases the lifespan, or
c) a combination of the above, i.e. you have to tolerate a reduction in efficiency to get a reasonable lifespan. 120V lamps typically have 16% higher efficacy at 40W rising to 23% higher at 100W.

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Hi /g/
I'm looking for a way to control a total of five traffic lights with a minimum number of required microcontroller I/O pins. The traffic lights consist of three 3-aspect (red, yellow, green) and two 2-aspect (red, green) pedestrian lights.

I've been thinking of using a 74 LS 156 decoder chip. I could utilize its two address pins to select the aspect that should be turned ON: either red, yellow or green.
Then, by connecting the not-inverted (decoder A) and inverted (decoder B) enable pins together, I could apply low/high signal to it to select which traffic light should have its corresponding aspect turned ON.

The problem I see with this approach is that it does not remember its previous control. The microcontroller would need to constantly update the address and enable signals of the 74 LS 156 would need to be driven with a very high frequency for the traffic lights to not appear flickering.

Any thoughts about this?

>>1185442
>Hi /g/
The usual solution is a shift register like 74hc595, requiring 3 io pins. You can chain two of them to get the required number of outputs.
Another option would be 74hc259, which is a bit-addressable latch. It requires several lines more (6 for 2 chips), but it might be more pleasant to use.
Then there are various I2C IO expanders, which need only 2 io pins, but are more tedious to use than the above.

>>1185461
you can get by with two pins on the 595 if you tie the latch clocks to the last qh' and clear to the last qh through an inverter (rc delay may be needed, i'll find out soon lol)

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I'm trying to reverse-engineer a headphone tube amp, or a small part of it anyway. I have literally no idea what I'm doing so what better place to start? Any input would be much appreciated.

>>>/g/60663831

>>1185310
That makes sense, but I suppose it's becoming less relevant now with incandescent lighting being phased out pretty much everywhere.

>>1185521
Looks fancy. Obvious or not, the first challenge is getting the whole thing apart in a way that doesn't damage anything and allows it to be reassembled. Unplugging the tubes from their sockets is probably a good idea. Once apart you should photograph both sides of the board(s) with as little skew as possible, flip one side in your image editor of choice, and overlay the two together with some transparency so you can trace the circuit together. It's probably a good idea to draw over the traces and draw in the components by symbol, and add in the off-board components such as the tubes and potentiometer too. Check the datasheets of anything you don't know the pinout for, they're pretty easy to find if you know the part number. You can typically seperate the circuit into sections by purpose, so there will be one section for the power supply, and probably a section each for the input and output audio. This helps to determine the purpose of each component or set of components. If you're not too sure if something will work, try plotting it in a circuit simulator. I use LTspice and it's fairly effective (not to mention free), though a little obtuse. But for an amplifier you probably shouldn't have to do this, and you might even be able to trace the board by eye without board photography.

>>1185533
I don't have the amp. I'm just trying to figure out a couple of very simple PCBs and how they integrate with the amp (which I do have the schematic for).

I know some basic circuit stuff but not a lot about transistors, so I don't really understand how the circuits work, which is obviously a problem..

>>1185535
It's a bit hard to reverse engineer something you don't have. There are hundreds of amp designs out there, and while all somewhat similar in nature, there are many subtleties in their design. What information were you planning on using to reverse engineer this amp in the first place? There are a bunch of pictures of both the Speedball and the standard Bottlehead Crack, and combined with the diagram of the first I suppose you could attempt to recreate the Speedball circuit. I'd say the first thing to do would be to get a picture of the standard amp and map the components on the diagram to the amp itself, then map as many of those components onto a picture of the Speedball and see what's replaced with what.

Transistors can act either as amplifiers or switches. If acting as an amplifier they have a hFE coefficient which states the current gain from base (input) to emitter (output). A typical value is between 100 and 200, but they're not precisely manufactured for this. If acting as a switch, the transistor is saturated, and if there's a significant current at the base then the current will be allowed to flow from collector to emitter. In saturation, the current at the base is large enough such that the theoretical hFE*base_current is larger than the maximum current the circuit can provide. If you try to operate a transistor as an amplifier with too high a base current, it will be in saturation and all the signal will be amplified to what's essentially the same amplitude, and is hence very distorted.

>>1185554
I posted the manual which has the schematic and build instructions for the standard Crack. Building that would not be an issue. The instructions aren't great, but the schematic is there, so yeah..
The Eagle schematics I posted are the circuits I've traced myself from pictures. Each circuit replaces a resistor in the standard Crack. How exactly that works, and how it's wired up, I don't know. I guess I'll just have to look more into transistor theory.

>>1185561
Oh, so you want someone to explain how those traced schematics work and what parts to use to build one yourself?

I assume the replaced resistors are part of defining the gain for the amplifier, though what the LEDs are doing replacing them is meant to achieve is quite a mystery to me, assuming I'm looking at the right pictures. Are the LEDs visible on a completed Speedball? What is the Speedball supposed to sound like in comparison to the normal Crack?

>>1185561
I might be too tired to explain the whole thing but as a start: When you build an amp, you generally want the output to be a reasonable copy of the input, just bigger. We use so-called active devices like transistors and tubes to create amplifiers with gain, and different topologies/strategies result in varying levels of fidelity.

The Crack looks to be a common cathode stage followed by a common plate (more commonly called a cathode follower). The CC stage provides gain, and the CF stage acts as a buffer. Why two stages? The CC stage can't simultaneously provide high gain and drive low impedances, and CF stages don't produce voltage gain.

Now about the plate resistor on a CC stage. What the CC stage does is turn a voltage wibble on the grid into a current wibble through the tube. The plate resistor turns that current wibble back into a voltage wibble. So what's the problem? Well I've forgotten exactly why you want to do this but in most cases replacing the plate resistor with a honest-to-god current source helps your gain and fidelity. Maybe somebody else knows, I think I'm done for the evening.

Hi ohm/ i have a problem with my wiring in my aprtment. And was wondering if anyone could help me out.
Two questions

1. What is it called when there is a conductive connection between the lines that run power and earth?

Because this is what i believe has happened. Since my fuse keeps popping out when i try to turn it on.

I think i know that to locate the error you measure resistance between live and earth with a tool that indicates Megaohm.

2. I dont have this tool but will I be able to measure with a normal multimeter?

Any other tips will be much appreciated

Using an L298, do I need to add the flyback diodes myself, or are they included in the IC? Couldn' t understand from the datasheet.
Also, are diodes necessary for all types of motors? Or do I not need them if I'm going to use a stepper?

>>1185866
Well, is it the fuse or is it your RCD/RCCB/GFI/GFCI/whatever (it's called something else in my country, don't know where you're located).

>>1185872
Hi located in Norway. My fuse says eart error/issue. Whithe the error coding on the fuse. Green blue green. The fuse will not switch on.

Can i measure earth continuity from earth to every socket with a normal multimeter? Has this been done before? It will cost me atleast 1000 gbp to get someone in and check. And that is without fixing it. I have been studying electro a bit and feel confident i coul try trblshootin myself

>>1185874
Have you tried disconnecting everything in your house?

>>1185874
My fusebox doesnt have a designated rcd. Only a main fuse and four auto fuses. Although all of these have earth. All good quality eaton auto fuses maybe one year old

>>1185875
Yes. Thank you for the advice

>>1185872
>>1185875
>>1185876
In theory; if i get a long enough cable for my multimeter, it would work as a megger instrument right?

>>1185874
Could you take a picture of the installation?

>>1185880
I'm not sure you even need to use a megger or a multimeter?

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>>1185884
If you mean the cables they are hidden. In walls/ceiling. Here are the fuses. The one that doesnt shine with green light has the two triangles green and the sqare in the middle blue. This should mean earth issue acc. Eaton

>>1185886
Huh, interesting. Never seen anything like that. Convenient for troubleshooting. We just use a single RCD/whatever.

Things should be daisychained at the outlets, so you should be able to disconnect parts of the circuit and figure out where the problem is, no?

>>1185886
>>1185889
Like a divide and conquer thing. So say you have 4 outlets, you'd disconnect the last two and try powering it on. Problem goes away and you reconnect things and disconnect the last outlet. Problem comes back and you've found the faulty cable.

>>1185889
Yes. Thank you for the advice. That will be my next step. Im afraid my neighbour upstairs has come across my ceiling cables when he was working on he's floor. Although that was 3 weeks ago

>>1185893
Np. I'm not an electrician, so I hope what I've said makes sense.. I have worked with troubleshooting cables/installations. Mostly with a megger and on outdoors installations where moisture gets in, but seeing as you know where the fault is, I don't see how it would be of any use here.
Let us know how it goes and don't electrocute yourself.

>>1185897
Yeah. Tnx. A megger would be ideal if this doesnt work. Hopefully ill be able to rent one

>>1185900
Maybe I'm just retarded but I don't see how the megger would help you. Since you have an rcd on every circuit you already know where the fault is.

Wouldn't the megger just verify that there is a fault on that specific circuit, and not get you any closer to pinpointing what subsection of the cable the fault is on? If you were to measure on each outlet, all would give you a fault since they're all connected?

Also, I'm thinking you should be able to find the fault by just disconnecting the PE/ground at various locations using the same method as I said here >>1185892

>>1183261
>Getting Started in Electronics Forrest Mims III
Thank you OP

>>1183261
>>1185942
https://lost-contact.mit.edu/afs//adrake.org/usr/rkh/Books/books/electronics/

>>1185937
>all would give fault cause all are connected

Damn I'm the retarded one. Ofcource they would!
Cheers pal! that atleast saved me some time and money!

>>1185775
Something like that yeah - and potentially verify the circuits, tell me how to wire the boards to the rest of the circuit.
The LEDs are not visible, but used in biasing the transistors from what I can gather.

The speedball is supposed to make the bass tighter/faster or something to that effect.

>>1185806
I appreciate the effort. I will have to look more into this. Might have to put it on hold for a while though.

I do know the basics of how transistors and tubes work, but then people start throwing words around like constant current loads and stuff, and I can't keep up any more..

>>1183669
Only issue is voltage doubler swaps A for E so you won't get much amperage (prob only a couple mA)

>>1183850
Seems about right but realisticly you'll have resistors and other cap hooked up to it, so don't expect 120 out of it

>tfw you gotta write a cover letter to apply for an internship but you can't be bothered
Just give me the job please

So, how do you use a microcontroller for real-time DSP? I get the A-D conversion, but not the programming. What language would it use? Would it just read data every clock cycle?

>>1186030
I think the"constant current" supply is just the amplification of the transistor at work. By feeding a current through the base of the transistor instead of directly, the current will not sag like it would through a resistor to the same extent, but rather to a factor of the transistor's hFE/current gain less.

>>1186141
Every time you get a sample from your ADC, you run your algorithms. Or you collect several samples to a buffer and when you have enough, you run your algorithms (while the ADC is filling the next buffer). You can also combine these two approaches.

Typical language choices are C and (if needed) asm.

>>1186141
to elaborate on basic functionality in case that's what you're asking, microcontroller adcs work by setting a register bit to start conversion and then doing other things (or nothing) until the adc sets another register bit to indicate it's done. that waiting time is ideally when all your math gets done.

>>1186124
i just reviewed 9 peoples' resumes for an entry level engineering position and only one had a cover letter. it didn't help him. i hear they're more common in europe but if you're american you'll likely be fine.

>>1186167
>>1186182
How do you program a PIC microcontroller? Say,
https://www.digikey.com/product-detail/en/microchip-technology/PIC16F54-I-P/PIC16F54-I-P-ND/613198
, for example. Do I have to buy the $50 kit? https://www.digikey.com/product-detail/en/microchip-technology/PG164130/PG164130-ND/2171224

>>1186188
for that one, and most old pics, you can get a chinese pickit 2 knockoff from ebay. mine had a tombstoned resistor that vanished into the carpet but i soldered on a 1k axial and it worked. some assembly required i guess. if you're not poor the pickit 3 will guarantee compatibility with the newer pics with nifty analog peripherals.

>>1185874
> located in Norway
Apparently Norway has a really weird-ass electrical system, used only in Norway and Albania.

I don't know the details, just what a (non-electrician) Norwegian friend told me. But I think there's no common neutral/ground wire in the network, just 3 live phases, with neutral being synthesised locally.

I was told that a common issue with the old coaxial ethernet cables was that connecting them between different buildings could result in substantial current running through the screen because of differences in ground potential.

tl;dr: any advice you're given by people here probably doesn't apply to Norway.

>>1186188
You need a programmer, unless the PIC has already been flashed with a bootloader (in which case, you can program it via RS-232, or USB if the PIC has a USB interface). Some hobbyist-oriented sources sell pre-flashed PICs, but the choice is limited and prices tend to be higher.

The last time I checked, you can get both the schematics and the firmware for the PICKIT from Microchip's site, but that still leaves you needing to flash the PIC in the programmer, or getting a pre-programmed PIC.

So I want to make a small filter with a 12V fan to suck away the solder smoke from me.

The thing is, the arduino kit I bought has only a 9V battery in it. (I know I can just look for a 12V batter)

But I want to know if it's possible to make a voltage amplifier with a transistor. Since I took a class and learned how to design one (though we used a function generator and a DC supply,) is it possible to amplify a 9V battery with a transistor to a V out of 19V?

tl;dr: can you amplify a 9V input to 12V output with a transistor?

>>1186230
It looks like I can do it with a few discrete components, a serial connection, and some software. See
https://www.digikey.com/product-detail/en/microchip-technology/PG164130/PG164130-ND/2171224

>>1186252
Class A amplifiers, which I think you're talking about, work by having a higher supply voltage, which is then lowered a bit in proportion to the input signal. So that wouldn't work for you. But there are DC-DC converters that can increase voltages. The best one for this application would be a boost converter. The best thing for this application would be to get a bigger battery.

>>1186259
Oh, so I guess just get a 12V battery and get over with it? Or 2 6V?

Since DC-DC converters may be difficult to build?

>>1186260
if you have a 555 timer, a trim pot, a few passives, and a power inductor + power transistor (all things you want to have in a junk bin) you can make one that'll work fine with the constant load a fan presents.

>>1186260
Hell, you could even get 8 1.5V batteries. The world is your oyster.

>>1186262
wew
>>1186263
Yea we never practice with actual batteries in the lab unfortunately.

>>1186264
if you don't have those or an arduino you can't convert 9v to 12v. i have a computer fan that runs just fine on a 9v battery though. i used it when my ac broke.

>>1186265
I do have an arduino but not these components. The 12V fan I have runs on the 9V battery, but I don't think it runs at its intended capacity.

Oh wait, you can amplify a 9V battery from an arduino?

>>1186267
sorry i misspoke. you still need a power transistor, inductor, two caps, and a diode if you use an arduino. you just don't need the 555 bullshit.

>>1186269
Do you have the schematic for that? What is it called?

>>1186252
Short answer, no. A transistor can amplify base voltage only to the maximum collector voltage. When used like an amplifier, there is always a significant supply voltage range that is larger than the audio signal will ever be. Amplifiers have a set gain, so if you try to amplify a signal that multiplied by the gain is greater than one of the supply rails, the wave will be clipped and have a flat top, which is called clipping distortion.

Long answer, not without any other components. Typically this is done in one of two ways.

The first is the boost converter, which uses a transistor along with some sort of oscillator to turn the supply voltage (9V in this case) on and off continually. When on, this current flows through the inductor, and when the transistor switches off, there's energy proportional to current, so there must be a current. The current flows through another part of the circuit instead of through the transistor, regardless of any resistance in its way. If the resistance is high enough, the voltage through V=IR will be higher than 9V, albeit momentarily. With some sort of linear voltage regulator to stop it from getting above 12V, and a capacitor to buffer the output voltage to stop it going too far below 12V, creating a stable 12V supply.

The second is a flyback converter, which again uses a transistor along with some sort of oscillator to turn the supply voltage (9V in this case) on and off continually. This voltage is fed through a transformer, which multiplies the voltage by the ratio of the number of turns on each side, minus a few losses. Again you'll need filter capacitors, but if you selected your transformer correct you won't need voltage regulation. The higher the frequency in both these methods, the more efficient they are.

There are other methods, some of which do not require inductors/transformers, but they pretty much all require some sort of oscillator to make an alternating current.

>>1186270
It will just be a boost converter that uses the Arduino to produce the alternating current. You could even have feedback to control the output voltage based on the transistor's duty cycle and eliminating the need for a linear regulator, if you're up to the challenge.

>>1186271
But instead of all that, I'd use a 12V source to begin with and use a linear regulator of some variety to get the correct voltage to the microcontroller. A linear regulator is far more simple, albeit a little lossy. It's essentially a voltage divider, but typically you use a Zener diode or something similar to obtain a constant output voltage that doesn't depend on the load current.

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>>1186270
boost converters are scary but simple ones still work fine if you cobble them together with no idea what you're doing.

>>1186274
>arduinos have onboard regulators
What kind of voltage could you put across them before they'd get noticeably hot?

>>1186280
it really depends what your outputs are drawing. dissipation on just the chip will be 5V@8MHz->63.4mA*(9V-5V)=250mW. i wouldn't exceed 500mW in the regulator so that leaves you 60mA to waste on outputs. driving a power FET at high frequencies can consume a lot of current but unless you really fuck up it won't exceed 60mA average.

dissipation at 12v (max input for the arduino micro regulator, mic5219) will be 63.4mA*(12V-5V)=440mW. i frankly wouldn't want to go above 9v

>>1186287
oh and also since you're running on a battery here i'd suggest that you fuck with registers to get the arduino into the lowest power sleep mode that still lets you have the PWM timer on. it'll make a huge difference.

http://led.linear1.org/led.wiz
35 source voltage
7 volt LED
700mA
5 leds total

in series it says this is ok
this is what I do
but what if my power supply starts to do 36 volts the wizard now says my resistor is getting too hot?

I have 2 watt resistors (the wizard recommends 1 watt so I am safe there)
does that mean the heat won't be an issue?

I just want to be safe with my input voltage because maybe it does go u p and down...

>>1186294
are you sure your leds are 7v? anyway this won't work. you need a sufficient voltage drop across the resistor or small variations in forward voltage will massively vary the current. if your Vf was 6.7v you'd see 35-(6.7*5)=1.5W dissipated. Vf increases with current so this would be slightly better regulated than i'm suggesting but still not enough.

>>1186305
Yes I am sure. They are 6-7 volts and 700mA rated.
My others are 34 volts but I have those figured out since I don't do a series with them. All of mine are super high power LEDs not like the tiny ones used in circuit board stuff.

What do you mean it won't work, what the wizard says is wrong completely?

I thought that too, my friend didn't comment about it.. all the LEDs are SLIGHTLY DIFFERENT, right? So one might want 750mA and one might want 690mA?

>>1186307
their brightness will vary slightly at a given current but not enough to bother accounting for that. what actually matters is the variation in their forward voltage with temperature and between parts. the wizard is right only for the precise 7v forward voltage you gave it. if your leds are below that on average then you'll get a higher current, which will run them hotter, thus lowering the forward voltage, causing more current, etc.

what you can do for better results instead of using that calculator is to find the forward voltage curve for your leds and map out a resistor value that works with the curve at ~70c. R=(35V-5*Vf)/I, but I varies with R and V varies with I so you need to iterate to find an equilibrium. if your leds don't have a published i-v curve then using them in your proposed configuration is poor practice at best.

>>1186312
So would you recommend I drop my input voltage to 6.5volts and run the LEDs in parallel instead?

giving it

6.5 volts positive -> led -> 1 ohm 2 watt resistor -> back to negative

for each individual LED?

>>1186312
or should I get a 10 watt resistor?

>>1186323

using small series resistors is dangerous, as the other anon said above. using larger resistors is a lot safer but wastes a lot of energy in heating the resistor. ideally you want to use a constant current source, so variations in the LEDs become irrelevant. you could wire up an LM317 for each LED, or every couple of LEDs, but once again you're creating a lot of heat.

the best solution is a switching constant current source like the ones sold here: http://www.ledsupply.com/led-drivers/buckpuck-dc-led-drivers

these are for DC-powered sources, other models exist that connect directly to 120Vac.

>>1186332
I have that already, but when running hundreds of leds on a board and switching properties the input voltage changes so I have to re-dial those in for the perfect "correct" voltage..
every house has 110VAC - 130VAC in USA for the most part and it's all over teh place causing very slight changes.
and the one you linked is insanely expensive compared to like.. every other one.

Stupid question, but does the audible whine from the step-up circuit in electric fly swatters scare insects away?

>>1186361
I'd say the moving meatbag attached to the other end of the swatter repels them much more.
In other words, I highly doubt it, but it would be interesting if it were true.

how come inductive motors can draw way more than the breaker allows without throwing it? my bench grinder draws over 22 amps on startup and i was testing a 240v 5 horse motor on 120v just to see if it worked and it drew over 35 amps for 10-15 seconds without tripping the breaker

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>>1186501
Take a look at pic related. A breaker can sustain its rated current for an indefinite amount of time, and the higher you go above that the less that time becomes. The instantaneous tripping current is 3*rating for a B, and 5* rating for a C.

I have a stereo amplifier that i want to use to power 2 subs. If i use a low pass filter pre-amp that also converts a stereo signal to a mono signal that i would then connect to the input of my amp, would it then send out the filtered frequencies through both left and right channels of the output?

Or do such amplifiers need to have a stereo input to begin with?

>>1186551

very odd question. the left speaker will put out whatever signal you feed into the AUX (or TAPE IN) left signal, and the right speaker will output whatever you feed into the right input.

so if you feed the mono signal into both L and R inputs then both speakers will play the same mono sound. whereas, if you feed it a stereo signal, then you get a stereo output. this latter is the preferred method, but requires a stereo preamp, or 2 mono preamps.

>>1186559
No thats not really what i meant. My amplifier has 1 input (positive - negative) and 2 outputs (left - + , right - +). Now my question is if i can send a mono signal into this amplifier will it then send that mono signal to both speakers, wich is what i want because i'm powering subwoofers so a mono signal output is no problem.

My portable battery stopped charging itself all of a sudden and I'm trying to fix it. When I opened it I noticed that the micro usb port is soldered with two blobs covering the +5v side and some of the pins in the middle and the same on the - side, with about a 1mm gap between the blobs. Could this be the problem or should I look into it further?
No other components on the board are visibly damaged.

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Is filling thed LED holder with hot glue to stick the LED and preventing the wires from touching each other a bad idea? I'd just squeeze a healthy amount down there

>>1186569

a picture would help, but i'd say the blobs are more likely intentional than a fault. they simply soldered the data pins to the power pins coz the data pins arent used in a charger.

>>1186566
>My amplifier has 1 input (positive - negative) and 2 outputs (left - + , right - +)

this doesnt sound right at all. especially since you called it a stereo amplifier, which typically means you have a whole slew of RCA jacks in the back. could be it uses a 3.5mm stereo input. a picture would help. also, trial and error will give you the answer you seek in under 30 seconds.

>>1186590

yes its a bad idea, coz you're creating a poopy mess. you should always build with the goal of being able to take it all apart and reusing all the parts. heat shrink is the way to go. if you dont have any, just using the tubing you create when you strip a wire. like, if you have an old broken mouse, that'll give you about 5 feet of tubing of about the right size.

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Hello.

I need to find some socket that could fit with this one. Any idea ?

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>>1186599
That's the best my phone can do unfortunately.
The problem is weird, it shows as if it were charging, I leave it plugged in overnight but the status led still shows that it is drained in the morning. The usb port also gets quite hot to the touch when plugged in.

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im using a dryer plug to power a 240v project. its a nema 10-30 and has no ground pin. the motor on my project has a ground wire and i would like to use it so i dont accidently die. do i just use the neutral as a ground and hook it to the frame?
also, will multivoltage electronics work with 2 pole 240v or are they only intended for use with a neutral?

>>1186590
Ever heard of heatshrink tube? It will change your life.

>>1186631
Run a separate ground wire from the motor to a ground. Do not use the neutral.

>>1186694
Duh because Then I'll just get 120 though my shit rather than 240. Shoulda not been retarded from the start lol. Luckily the house ground rod is next to the garage.

>>1186745
How do you find your ground rod? I've just been tying my experiments to my plumbing to avoid the tripping the ground-fault breaker, but it would be nice to have a solid electrical connection instead. I don't have the house plans by the way.

>>1186869
It's easy for me, it's literally poking an inch out of the ground near my garage. But I live in a little rinky dink house in Alaska where the rules are made up and building codes don't matter so that's probably the reason why It was so easy to find for me.
I would say just take a multimeter poke one end and a ground plug and the other end on piping and long as you don't have over something like 10k of resistance then you're probably good to go

i have a go kart with a stator that puts out up to 6 amps, however the voltage varies from 20vac at idle to over 75vac at redline when unloaded. i hooked up an h4 headlight and it drew 1.5 amps and brought the voltage down to a more reasonable 8 to 16vac or so. the kart also has a small battery and electric start so charging the battery with the stator would be ideal, however even if i rectify it the voltage would be far below charging levels and with the gigantic unloaded voltages it makes i dont think i can just use a dc to dc regulator but the ac isnt high enough for most 120-240v ac to dc converters. how do i get a stable 14.4vdc from this cunt?

If I'm trying to step down DC to lower voltage DC(Say, power tool battery to 5v for a Pi), a buck converter is what I need, right? I'm only vaguely familiar with the electrical side of things, but I have a small Raspberry Pi project I want to do.

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>>1187028
>varies from 20vac at idle to over 75vac at redline when unloaded.

Doesn't mean anything.

>>1187028
>i hooked up an h4 headlight and it drew 1.5 amps and brought the voltage down to a more reasonable 8 to 16vac or so.

This is the important measurement.

>>1187028
>how do i get a stable 14.4vdc from this cunt?

By adding a diode like Briggs does and allowing the battery to stabilize the voltage.

At idle it won't be charging but a higher revs it will.

It doesn't need to be charging all the time - just enough to replace what was used to start the engine.

As you can see in the pic, Briggs just puts a diode in the lead from the stator to the battery.

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Alright, got a question from work that I imagine someone here has experience with. If anyone wants to chime in I'd love the help

>Customer had a paint line for automotive parts
>Originally set up for a paint robot right before the 180F cure oven for reasons
>They had to pull the robot out because operating in high heat, high humidity conditions 24/7 was hell on it
>Replaced robot with a flowing "paint curtain"
>Now have some accumulation problems with the paint, so they want us to make an air nozzle setup to flash the parts (will probably weight at least 20lbs when done)
>Enter the problem: The mount for said nozzles everything is attached to has to be able to go to multiple vertical positions depending on the part
>Everything is still in the high heat, high humidity area
As for the position control itself, our first thought was a a linear encoder, but I haven't been able to turn up anything rated for that high a temp
Looked for rotary encoders, same issue
Found 1 company with hydraulic rod encoders that *might* be ok at that temp (Still waiting on clarification from them), but we would be a LOT better off with an air cylinder
Even thought a hefty stepper motor + acme screw might be good, but only found 1 place with high-temp stepper motors and I'm concerned about them having enough torque

Any thoughts?

>>1185508
Can run it off a single pin using a pair of RCs if you don't mind one bit always being zero http://www.romanblack.com/shift1.htm

>>1187050
I presume you have ample shop air so you could run tubes to the encoders to keep them cool.

You can also use air knifes to protect them if you like. Forced air would greatly reduce paint residue accumulation too.

>>1187050
outsource the sensor by decoding back emf from the leads of an idle brushless motor attached the same way as an encoder.

>>1187031
Yes.

>>1187039
The battery won't mind taking 15-16v for minutes at a time at full throttle?

>>1183669
It should work fine, just don't expect big currents out of it (maybe only a couple mA) also try to do the math for the load since voltage will be all over the map with a unknown load.

>>1187276
The battery will load it enough that it probably won't go that high.

It's SOP for lawnmowers.

>>1187290
Ok thanks I'll give it a try

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>>1183261
This is off my garage opener. Some relay thing. Can anyone tell me what I can do to replace it? All I've found are the patents online

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>>1187388
2/3

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>>1187389
3/3

Any help is appreciated. Here are where the patents are

Https://www.google.com/patents/US3825809

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>>1187388
>what I can do to replace it?
Are you sure this is the problem?
If this assembly is actually the problem you'll probably have to repair it or replace it with the same type apparatus.

connect the black wires to 120vac
touch the long red and long brown wire terminals together - the relay should click
if the relay doesn't click, check transformer and relay coil for continuity
if the relay clicks, check the switch the relay operates by measuring continuity between the yellow & blue wires and the yellow & red wires from the switch with the relay energized and not energized

>>1187454
Quite certain

Okay will do. Thank you

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>>1187457

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>>1187470

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>>1187473
Yes, thank you.
I need to study this a bit.
I think it operates in a manner similar to pic related

>>1187482
The patent is that the garage can hold at open/close. Like it can pause. It's from the 70's

>>1187473
I see how energising the relay/coil would push the wedge into the groove and torque the microswitch(es), and I guess it mechanically toggles each cycle? If they're acting like a centre-off SPDT switch then I can't see how it would act as an H-bridge for the motor, wouldn't it have to be a DPDT switch?

In any case, does it work in only one direction? If this is the case, I'd say you might need to lubricate some of those plastic parts.

Complete novice here. So I have managed to program two servos to move when I hit a button and I'm powering it via USB, I want to try an run it off a battery. I understand how to power my micro controller alone by battery, but I don't understand how to the servos work into the equation. The servos need 6V each and the micro controller needs 7v, so do I just add up the total voltage (19V) and use a battery that supplies that voltage roughly?

I'm trying to diagnose a parasitic draw in my car so I've gotta buy a multimeter tomorrow. I'm broke and don't wanna spend a lot, is Cen-Tech good for automotive use?

https://www.harborfreight.com/7-function-digital-multimeter-92020.html

Is the 10A model good enough or do i need the 20A?

https://www.harborfreight.com/ac-dc-digital-multimeter-37772.html

Assuming i use the 20% off coupon i could get that for less than $20, so can i find a better meter for the same price as these at Home Depot or Walmart?

>>1187509
no. you need a 7v battery (in reality a 9v might work for you). all the components need the same voltage and then they consume the sum of their currents.

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>>1187473

You should be able to make the bottom lever
toggle back and forth by pressing the arm of
the relay down with your finger then releasing
it and pressing it down again. It should flip each
time you move the arm.

Does this mechanical action work?

>>1187511
Thank you, I was confused but now I get it.

>>1187510
All cheap multimeter brands are pretty much equal, I wouldn't put too much thought into in unless you want to measure engine startup current or mains voltage. Cen-Tech is not a name brand, probably just a HF home brand anyways.

Now that first model is pretty much the ubiquitous one cheapest multimeter, but since everyone manufactures them you can be fairly sure that they won't blow up when you don'd go over their ratings. I've got two. They're what you get if you're stopped for cash or will never use it often. The second model you showed is much more multi purpose, but it really doesn't matter for what you plan on doing. If you ever plan on measuring high current anyways you should just buy a current shunt of a few mΩ (less than 10) and measure the voltage across that instead, but for parasitic draw there really shouldn't be over 10A unless your battery is really draining fast.

In regards to price you can probably get either one at half that price from china, but I wouldn't really trust them that far, and the shipping takes a couple of weeks at most unless you want to spend $20 extra.

What are the symptoms of parasitic draw? If we know how long it takes for the battery to completely discharge (possibly partially too) you can work out how much current is being drawn.

>>1187559

The car sputters to a start if i don't run it for 4-5 days, so the parasitic draw must be something small. The previous owner installed an aftermarket head unit, but I'm not sure if he spliced into any wires. Thanks for the advice, I'll buy the 20A model that offers the audible continuity so i can quickly check fuses. Once i learn more about electronics I'll get something nicer like a Fluke.

>>1187604
You're probably getting less than 100mA of current, from ballpark figures. Good luck.

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I don't know if i should make a thread about this, anyways...
Why 2nd picture wouldn't work? I am an electronics noob and i really cannot find an answer.

>>1187510
Get the cheap one. I got it for free from them with a coupon, see if that's available. The brand name is nothing

>>1187634
You see, a Tesla coil is a high frequency oscillator, usually somewhere in the MHz range. This is why you burn yourself instead of shocking yourself when you touch the very high voltage it produces (skin effect or something). An inductor stores energy in its magnetic field (how transformers work) by having current pass through it, while a capacitor stores energy in its electric field by having a voltage across it. By coupling a capacitor and inductor together, you can get a resonance oscillator, where the energy goes from the capacitor, into the inductor, then to the capacitor in the other direction, and back and forth. This very high frequency oscillation is what the primary coil uses to transfer energy to the secondary in what would typically be a very inefficient transformer (frequency is proportional to efficiency), and hence get the voltage very high (primary to secondary turns ratio = primary to secondary voltage ratio).

How that actual circuit works I have no idea, I guess the spark gap is used as a dirty automatic switch that lets the voltage build up or something.

>>1187638
Wow... Thanks for the great and easy to understand explanation! I am glad to be finally able to understand what's the relationship among the capacitor and the inductor.

>>1187513
Sorry I went to sleep.

Yes it flips every time you operate the relay arm

Anyone here care to share first hand experience with chinkshit soldering stations? Or should i just save enough for a Weller/Hakko?

>>1187751
It's pretty gud, didn't burn down yet. I have a ZD-919 analog controlled one with a 45W iron. I didn't check the temp accuracy but it performs just fine for the projects I do and the occasional desoldering. If you get one, check that it is properly grounded and fused before you plug it in.

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>>1187638
>spark gap
spark gap is for sound effect and ozone smell

>>1187744
>Yes it flips every time you operate the relay arm
Does the relay operate when you >>1187454
>connect the black wires to 120vac and
>touch the long red and long brown wire terminals together?

I wanna get into robotics, especially androids. What are some good resources? I suppose I should learn about algorithms, linear algebra, dynamics and the likes, right? I have an engineering background btw

>>1187820
do you have an engineering background or an electrical engineering background? if it's the former then read about the various types of motors, how to drive them, and what preexisting control boards are out there.

>>1187820
Start with Inverse Kinematics

I have a Li-ion battery that I plan to use for a first electronics project, but I want to avoid overdrawing it and damaging it. Can someone point me in the right direction?

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What would happen if I took a basic op-amp inverting amplifier and did something ridiculous such as replace the feedback resistor with an active low-pass filter?

>>1187969
Get yourself one of these mother fuckers. https://www.amainhobbies.com/team-integy-lipo-voltage-checker-w-warning-alarm-intc23212/p183759

>>1187979
Are the op-amp outputs connected together? I don't think that makes any sense. If you want to lowpass the feedback path the extra op-amp stage should be going right to left.

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>>1187979
Let's ask LTspice!

Anybody know what sort of flux to use when soldering onto aluminium wire? I'm fixing a few open circuits in a transformer secondary.

>>1188009
Solder doesn't take well to aluminum if I remember correctly. I'm not sure about flux but I know roughing up the surface usually helps. Run some sand paper or a file over the part of the wire you'll be soldering.

>>1188011
Already sanded it up, did not stick. There are fluxes out there that get rid of the oxide layer, just wondering if anyone here has any experience with this from an electronics standpoint, and whether there's a flux that works with 60/40 electronics solder.

>>1188009
You need aluminum solder. It contains zinc.
Or, if you're really desperate, you can try rubbing/scratching the aluminum surface when it's under a blob of molten solder. This doesn't work well, though.

>>1188019
Looks like I want some 91:9 Sn:Zn solder, or something similar. If I'll need a special flux to use the zinc solder I might as well look for one that works with lead solder if it exists.

>>1188009
There is some fluxes for aluminium... But you can try to tin the wire under oil, by scraping wire with iron. At least it worked for me.

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I will be dumping some old, probably 70-80s soviet electronics. I wanted to ask if there are any uses to them, or maybe i could just sell them.

hey guys, i just turned 18 a few months back and will be starting college in the fall, id like to get into electronics diy stuff but my backwater redneck town doesnt teach a lot on this stuff, and anyone local thinks you can do it all with spare wires and electrical tape. I just want to learn the basics and start from there. Pls help, thank you.

>>1188123
>Pls help, thank you

Here ya go. >>1183261

>>1188009
pull the ends out a little and put a crimp connector on

>>1188123
do you want to learn about repair, arduino style diy, or electronics design?

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>>1188116

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>>1188156

>>1188164
That is a weird shape for a transistor. No wonder communism failed.

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>>1188176
Transistors come in metal cans in America too. I think it's a bit of an older style and it's not as common these days but it's still around. TO-5 and TO-18 are the package styles. TO-3 is also metal and much more common then the aforementioned package styles because it's usually used for power transistors that are bolted to large heatsinks or metal enclosures. I'm sure there are more that I've probably missed.

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>>1188116
Is your camera 70-80s Soviet technology, too?
Try to get shit in focus.

>>1188176
Some old Burger transistors were quite odd ass well.

I want to control a 3V light, but my microcontroller outputs 5V. Do I need a MOSFET, or is there some kind of transistor I can use? I need to keep the different voltages separate, so maybe I even need a relay?

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>>1188198

not enough info. if the microcuntroller can supply enough current, just put a resistor in series, calculated like so, R (in ohms) = (5V-3V)/(desired current in amps)

otherwise, a simple NPN emitter follower will work. (see pic - pretend it says "5V" on the base, and add a 1K resistor in series with the base)

I have a piece of electronics that came with a 12V 500mA PSU (DC), but the wire broke off. To replace it, I can use any other power brick rated at exactly 12V and at least 500mA, right?

>>1188211
Yup. I personally have been charging my laptop from an adjustable bench PSU for years.

>>1188211
yes exactly. congratulations on understanding because a lot of people seem to have trouble with it for some reason. match voltage, provide at least that current.

>>1188216
for the longest time i thought you had to proved MAX that rated current, because i thought that if it was rated for more (say, 800mA), it would actually provide that current and burn the device. Then I actually learned how electricity works.

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>>1188215
>>1188216
btw are power brick connectors standard? Like, will a 12V 500mA PSU always have the same size/shape connector no matter the brand?

>>1188220

if they were standard then some company would produce and sell ''standard'' laptop chargers at a reasonable price. but manufacturers like to use custom connectors so they can charge you monopoly prices for replacements. same with ink cartridges, toner, etc.

>>1188220
no. in no way shape or form is there any standard as to the size of connectors.
even worse as an example for i friend i replaced a barrel plug on a laptop charger for a friend. it works on 19V. all plugs i could find matching that size were rated 12V max. i hope it doesn't melt LOL!!! but thats kind of stupid i guess, gauge/surface is to do with current, voltage protection is to do with insulation thickness.

You need to measure the inside diameter and the outside diameter to find the right size. which is a fucking nightmare to do even with a pair of callipers the hole is too small to measure internal accurately.
i bought a dc plug with changeable barrel plugs that had the sizes molded into them, so i drilled holes in them and made a keychain out of them.

typical size (like 99% of the time) it's 5.5mm outside and either 2.1 or 2.5mm inner diameter just to fuck you. so it might look identical but either it won't fit or it will wiggle and waggle and not power anything reliably. good luck!

>>1188220
oh shit of course to make it even more difficult make sure the polarity is correct.

look for the little symbol with a plus and minus attached to a circle inside a crescent. tells you if the inside or outside is positive or negative. need to match that too.

>>1188220
>standard?
fuck, no. People slag off the EU, but, they forget what mobile phones were like, back in the day, literally EVERYONE had drawers full of damned chargers of varying uselessness, not just the /ohm/ shitlord hoarders on here.

Till Based Yurope proclaimed, Enough, enough of this Electronic Babel of BS - standard USB chargers you shall adopt, or, you can fuck right off. Apple were the worst, some new bollocks charger every 10 minutes, complete cunts, still are.

>>1188227
>>1188229
>>1188230
Jesus what a nightmare.

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Need to replace this after a mishap.
Markings are
E169
560
6.3v

Voltage is easy, but what does the E169 mean?

>>1188252
Can be a date code or type/series identifier.

>>1188257
So is it ok to disregard it so long as the resistance/voltage are correct?

>>1188262
That's a cap tho, no?

>>1188262
>resistance/voltage
looks like a capacitor but image is out of focus

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>>1188273
>>1188274
Looks like the pic except with E169 in place of E010.

>>1188176
>No wonder communism failed.

It failed because it wasn't true communism.
True communism has never been attempted.

>>1188277
560µF 6.3V I'd say, electrolytic Al capacitor. Marking/longer wire positive.

>>1188283
Uh-huh. And what is real communism? Is it that anarchist shit antifa are going on about? You want to die for Immortan Joe? Anarchism is the way there, you dumb fuck. Communism only "works" when people are forced to be communist with a death threat.

>>1188262
http://www.mouser.com/Mobile/Panasonic/Passive-Components/Capacitors/Aluminum-Electrolytic-Capacitors/Aluminum-Organic-Polymer-Capacitors/_/N-bmaieZ1yzvjj0/?P=1yyeh3hZ1yx4avt

Did you try?

>>1188289
Only one product has a lead spacing of 2.5
Pic has the wrong color ink on the cap, but it might not be accurate.
TSS or no TSS?

>>1188283
True fascism was also never attempted. Fascism did nothing wrong, Hitler just gave it a bad name by combining it with genocide. Though it's not like both fascism and communism aren't objectively bad governmental systems assuming imperfection. Whether it's giving the leaders the power over goods distribution or over manufacture, giving more power to whoever's in charge is typically a bad thing unless you have absolute proof that your leader can be trusted.

TL;DR: Let's stick with democracy until we get robot overlords.

>>1188283
>>1188288
>>1188408
>>>/pol/

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>>1188164
Soory for the bad photos, i was in a hurry

>>1183261
I want to use power mosfet to drain a lithium polymer battery fast as the mosfet can safely handle. when supplying the voltage to gate what is limiting the current since there is no resistors. the mosfet gate only draws the current is needs? i know the current on the drain side is controlled by the voltage. i would use power resistors but 1 high power mosfet sounds better than multiple resistors when you take money into account.

appreciate any replies

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>>1188544

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>>1188546

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>>1188547
The last one. Any ideas on uses, probably nobody would buy it...

>>1188116
Can't tell, could be anything

>>1188156
Can't tell, could be anything

>>1188164
Can't tell, could be anything (the part number was right there you fucking tard)

>>1188544
Can't tell, could be anything

>>1188546
> tfw only clear picture is in foreign language

>>1188547
Can't tell, could be anything

>>1188548
If we knew what the fuck it was supposed to be etc..

TL;DR; Learn to photograph you useless faggot. If you're in too much of a hurry to properly document shit then you're clearly not interested. Stop wasting everyone's time.

>>1188551
is this what autism looks like?

Is there a book that explains electronic components but on an atomic level?

>>1185866
Ground fault when it is between power and earth.

Short when it is between hot and neutral, or phase and phase.

>>1188544
Looks like transistors.

>>1188546
Capacitors, type K73-16; 3.3 μF; 10% (illegible); 250 V; 40 units; manufactured in September 1990.
How difficult was that?

>>1188547
Mixed worthless trash.

>>1188548
Dunno but that's a nice knob.

>>1188551
Most of his shit is transistors.

The one thing that isn't is the box of capacitors (condensers you condense fuck), which will be complete garbage by now. His last object is likely a variac. At least put your Autism to good use.

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>>1188576
>complimenting a man's knob

>>1188579
It's shiny. Your point is moot.

Can i build the coils of a resonant oscillator or any sort of inductor with the enameled copper wire used by the CRT deflection coils?

>>1188545
>fast as the mosfet can safely handle
I think your main concern should be how fast the LiPo can be discharged, not the FET.

>>1188553
You'll want something along the lines of a physics textbook. If you happen to be in Auckland city NZ then you could walk into the Uni bookstore and pick up “Transistor Electronics”, by Gary E.J. Bold for $20, but otherwise you'll have to look around a bit. Art of Electronics probably has what you're looking for, but you'd have to ask someone that has it.

>>1188602
Definitely.

>>1188610
225A discharge on the lipo. i just bought a mosfet designed for 890W with heatsink. ill prob only run it at 400-500W for the testing of heatsink until im satisfied it wont fry the mosfet lol

>>1187167
Don't see trying to keep the encoders cool as a viable situation because they're going to be inside the insulated cure oven, ideally running 24/7
While I really like the idea of an air knife (And will be filing away for future use), given the nature of the issue I don't imagine it'd work out great (Contour shapes on fixed angles, paint applied is relatively thick)

>>1187234
That is a very interesting idea as well, will look into that

>>1188610
I've been reading Art of Electronics and it has some stuff but not exactly what i want. I'll check out Transistor Electronics thanks!

>>1188610
You look quite experienced. Mind if i ask you which capacitor would be good for the thing? I do not know almost anything about electronics. However, i want to build a tesla coil (know it won't end up fine) but i want to build it anyways

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>>1188602

the wire from a TV deflection coil is gonna have all kinds of extra varnish to make it keep its shape which makes it hard to work with, and may expose some copper when you tear it apart. a much better source of copper is old iron transformers, the kind you'd pull out of an old ghetto blaster, for example.

>>1188610
> Art of Electronics ... but you'd have to ask someone that has it.

as if there werent dozens of torrents with that PDF in it. there's even a link in >>1185944 tho i dunno if that's the latest edition, which is the 3-rd edition.

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i made a thing, unfortunately now i get to write a driver for it before i know if it works

>>1187820

You need to learn about control systems, embedded programming, and analog circuits because a big problem you will run into is how to design amplifiers that drive motors.

Get a matlab simulink license if you can also.

>>1188843

Explain this to an amateur: How does USB even work?

I've tried to figure it out in the past and it feels like I'm a clown car on an airport runway and air traffic control is yelling at me

>>1188870
it's just a regular serial communication line like I2C or CAN, but higher speed, differential, and more featured on the firmware/software side.

a basic serial bus has a clock and data line. when the sender drives the clock line high, the receiver reads the data line as one bit. each bit is sent one by one that way and gets clocked into a register to be processed. usb foregoes a clock line by having each side have matched reference crystals/clocks with an occasional synchronization between them. also instead of one data line usb has two, one being an opposite mirror of the other. the receiver reads the difference between the two data lines. this means that when the lines pick up noise, it's about equal on each data line so it cancels out.

i don't know how it decides who gets to talk and when but that's on the software side which i try not to touch outside my nice safe box in visual studio.

>>1188903

So if you want to use USB to talk to a computer do you just buy an FTDI to do that or do you have to implement that yourself?

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>>1188843
it works. lessons learned:
>0805s work alright on 0603 pads
>there is no correct amount of solder paste for micro usb connectors, there will always be a short or a sparse pad
>attempting to add solder to the pegs on a micro usb connector results in solder spilling into the port
>shoving wick into the port to get the solder out burns the header, ruining it
>buying spares was a good idea

>>1188935
you can buy an ftdi style chip to emulate a COM port which makes things extremely easy. see pic. the actual ftdi chips are overpriced and ftdi is a shit company, get silicon labs parts or the CH340g (which i used) instead. you can also get microcontrollers with usb transceivers in them but i haven't tried those.

>>1188937
A-are you holding up ok?

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>>1188985
you what

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I have a 22$ 10Ah Power bank with 2 USB ports. One is 5V 1A and other one is 2.1A 5V.

The power bank uses a seperate DC-DC boost converter for each USB port to step up the voltage to 5V from whatever voltage the Lithium-Ion batteries provide.

Would it be more efficient to draw 0.8-1A of power from the 1A port or 2.1A port.

tldr: When does a boost converter work more efficiencly? At 50% load or 100% load?

>pic related

>>1189168
If you want to make this simple for yourself, just get a 2S LiPo and slap a regulator on it.

>>1189168
>50% load or 100% load?
Max efficiency close to max power because of heat, I would use the 1A port. Can you charge and load at the same time? I'm looking for a simple 5V UPS.

>>1189298
Thanks for input.
Can you charge and load at the same time? I'm looking for a simple 5V UPS.
Yes you can.But consider that he 4 indication LEDs are very bright and you cant turn them off while power bank is being used, but i don't know how much power they consume.

The one I have is 10 000mAh Trust urban primo powerbank

So far I am content with its performance. With one charge It charged my OnePlus X battery from 0-100% two times already. And I am charging my phone the third time now, will see how far it goes.

I have a question, lets say hypothetically I have an unlimited power supply that can meet up with a loads wattage but not its amperage (in this case an electric arc welder) will the load still function albeit not to its optimal performance?

>>1189352
>amperage
Stopped reading right there.
Also see >>1188211

>>1189382
voltage * amperage = wattage
voltage / amperage = ohmage

>>1189439
Voltage/potential difference is measured in Volts
Current is measured in Amps
Power is measured in Watts
Resistance is measured in Ohms

Welcome to the SI.

>>1189442
resistance is measured in ohmage

>>1189443
"X" is measured in "Y" implies that "Y" is a unit of measurement.
>How many "Ohmages" did you measure that resistor to be, Garry?
>I want you to fuck off, Paul.

>>1189446
not an argument

I have a handheld that has bad corrosion at a solder point where the wire connects to the AA battery connection.

I spot cleaned, but can i just desolder it, or do it have to clip back the wire and maybe the tip of the battery connector? (then of course cleaning the battery 'post')

The parts are pretty much impossible to replace, so I want to see if I have any options before clipping the battery post.

>toying around with a motor and a multimeter
>.38A when it's running at full
>.5A when it's stopped
What.

>>1189471
"stopped" means stalled. to stop a motor properly you need a switch to break the circuit.

>>1189472
The motor is driven with pwm. When it's running at full that means a constant HIGH, and when I'm saying stopped I mean a constant LOW. The circuit should be broken.

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>>1189382
>>1189439
>>1189442
>>1189443
>>1189446
>>1189447

>>1189486

I've heard just about everyone use amperage and wattage, but ohmage is plain retarded.

>>1189491
When making the png I looked up amperage and wattage knowing they were legit. I almost didn't even try ohmage but was surprised to find it was there too.

>>1189486
this guy gets it, i don't see what everyone's problem is with amperage. i mean we use this format all the time don't we?
when we measure a physical separation between two points we say meterage or inchage don't we?
we say literage or fluidounceage don't we when working with fluids?
gramage or poundage for how hard things are to lift for a given accelleration-due-to-massage.
luxage for how bright things are,
miles-per-hourage for how fast things go,
spendage for the little metal discs and paper notes with numbers we use to buy things,
the list goes on and on and on.

oh by the way if you guys all suck off horrowitz and hill (the art of electronics) as much as you all seem to then read the paragraph where it says if you use the word 'amperage' you are a fucking retard.

>>1189506
I think you'll find that lumenage is a more accepted unit.

>>1188610
>“Transistor Electronics”, by Gary E.J. Bold

I'm curious why you'd specifically mention a book you can only get from Auckland uni; is it that good? Can we get a few pages scanned?

>>1189544
Yes.
t. Gary E.J. Bold

>>1189506
-age is only okay in the words "wattage" and "voltage".

>>1189547
>-age is only okay in the words "wattage" and "voltage".

why? because i say so, and i am master of all the words. so what if ''amperage'' brings up 6 million hits on google? common usage be damned!

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I've got an old house, and am in the process of replacing the power outlets to one's that have a more modern style.

On the older dual outlet, one mains cable feeds each outlet, on the newer outlet the back only has connection for one - should I connect the two positives into the one slot, and so on for negative and earth?

Cheers

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>>1189671
I believe so, yes. I'm from Burgerland but from what I hear you crumpet suckers use a ring type setup for your electrical outlets. Picture related. So you should complete the ring.

>>1189447
My point was that Resistance isn't measured in "Ohmage", resistance is measured in Ohms. "Ohmage" is a term to replace resistance, not ohms. The correct (albeit informal and fucking stupid sounding) phrase would be to say "Ohmage is measured in ohms", not "Resistance is measured in ohmage".

Note that since "Ohmage" literally means "Resistance, as measured in ohms", the statement "Ohmage is measured in ohms" is a tautology.

The only reason we use these words is because other people use them; to have a common language of engineering/science. Since nobody else uses "Ohmage", you probably shouldn't either.

Do you argue that common usage should go out the window when it comes to conventional current too? Are you going to say that current is in the direction of the flow of electrons? Why stop there? Why not flip every electric charge polarity out there. Under the new standard used by you alone, protons are negative and electrons are positive. The physics doesn't change, though you might have to reverse the definition of the cross-product. You should start using Gaussian cgs units while you're at it, or natural units if you swing that way.

>>1189552
Voltage brings up 300Mhits vs 20Mhits for Potential difference.
Wattage brings up 30Mhits vs 3Ghits for Power.
Amperage brings up 6Mhits vs 2Ghits for Current.
Ohmage brings up 70khits vs 400Mhits for Resistance (and it's not in autocorrect).

>>1189547
>wattage
surely you mean active power

>>1189547
>wattage
Fuck right off mate, watts is a measure of power, the only time wattage is acceptable is if you are assisting a woman in changing a lamp.
>1189552
Wow something showing up on google must mean it's correct. Do you realise you are a retard?

Voltage only gets a pass because potential difference is too poncy.
>>1189671
Is it a DC supply? I'm only pulling your leg (that was a pun, the socket can be referred to as a 'leg' of the circuit!)
Dealing with mains voltage AC supply usually the terms phase/line/live are used for "positive" and neutral for "negative" because half of the time the phase is below or negative with respect to the neutral.
To be even more pedantic the phase/line conductor shouldn't be identified by the term ' live ' because both phase/line and neutral are considered to be 'live' don't ask why though (I don't fucking know).
To answer your question yes, put the two wires in the same hole.
Don't twist them together just push them in and clamp down. Give each one a pull y to make sure its secure. If it keeps falling out strip of twice the insulation you need and fold the copper over neatly with heavy pliers to double it up.
Where are you anyway? Another anon claims your in the UK, I'm on my phone I can't see the picture properly but the grommit at the cable entry is a funny colour.
Be aware of the current capacity, a dual 13A socket may not be able to safely provide 2x13A while the old socket with independent connectors may have been in a position to do so. I would avoid plugging in two space heaters or welders at the same time unless you check the rating first.

>>1189703
It could just as easily be a radial as a ring. You septics wire up sockets in star formations now?

>>1189671
That is some very old wiring and you should consider a full rewire, rather than just replacing outlets.

If you can't do a full rewire, carefully inspect the existing cable and be absolutely sure it is not one of the older types which is now not considered safe for use: if you touch it (even to replace the outlet) you MUST replace it. All of it.

It is especially important to ensure that it is not alluminium cable: it was popular for a while, but it is a major fire hazard and you CAN NOT connect it to standard fittings designed for copper cable.

Having said all of that: yes. Take the two cables coming into the box, twist together each of the wires (live + live, neutral + neutral, earth + earth) and then stick the pairs into the appropriate connectors on the back of the socket.

>>1189767
What's old about it not like its VIR it anything lol. Clearly copper if you look at it, even so what's the problem with using aluminium if you allow for the conductivity? You don't think the connector can handle it? What's the problem?

>>1189774
>Clearly copper if you look at it

You can't see the material used for the conductor. You can't tell from that picture what material is used in the insulation and whether it's degraded (some early PVC insulated cables do become brittle over time)

>even so what's the problem with using aluminium if you allow for the conductivity

http://www.faqs.org/faqs/electrical-wiring/part2/section-16.html

>>1189442
>Welcome to the SI.
All wrong. Names of units are written in lower case (volt, not Volt) unless first in a sentence. The symbols of the units are upper case only if derived from the name of a person (N for newton but m for meter).

>>1189777
You're actually right, never saw that one coming. I guess it's to differentiate the unit from the person? It makes sense especially if you're talking in a historical context.

o h m a g e

Any idea what microcontroller I should look for? I am doing a project where I have a switch with 4 states and it is attached to two motors. In each of these states the motors need to turn at different speeds and one even needs to fluctuate. I also need to fit this micro controller in as small a space as possible, think like 2 inch diameter of space. All I have are arduinos, any idea what would be the best choice for this kind of use?

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>>1189822

you should stick with a processor you know how to program. if that's the tarduino, there are guides on you can pull out the processor, from a Uno for example, and redo the circuit in a tiny form using only the parts you absolutely need.

alternately, you can purchase very small duinos like this one:
TinyDuino Microcontroller Is Smaller Than a Quarter
https://www.wired.com/2012/09/tinyduino/

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Finally running low on my little 2ml kit of Deoxit stuff, and after seeing how much it helps, I decided to pick up the 25ml needle bottles of Deoxit/FaderLube/Shield, but my little tube of Gold is still full. Am I just missing something, or is it basically Shield that doesn't protect as well, with a tiny amount of cleaning action? When would you use Gold instead of just cleaning with Deoxit and then protecting with Shield?

http://store.caig.com/s.nl/ctype.KB/it.I/id.285/KB.218/.f

A SIPO shift register I'm looking at buying a few of (74HC164) has a 500ns input rise-fall time, but a maximum clock frequency of 31MHz (at 4.5V). If I want to use these for variable frequency division with a minimum division of 2 (from a single flip-flop looped with a NOT gate), is the maximum frequency I can feed the device 31MHz, or some multiple of 1/(500ns)? I'm looking at a 4MHz crystal, and plan on making a somewhat variable high-accuracy frequency generator.

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>>1190015
Here's a diagram.

>>1190015
the input rise-fall is the absolute longest 10% to 90% voltage transition that the chip will still process without glitching. any transition time shorter than 500ns will work (eg not feeding it the output of an RC filter). any frequency will work below 31MHz.

>>1190034
Good, thanks. I guess the outputs will have a <500ns rise-fall time?

>>1190044
yes unless you load them with more than a few hundred pF on the output (eg with a mosfet gate)

>>1190047
I guess I should use a buffer to stop that happening? Maybe I could use inverting buffers instead of inverters and avoid the problem entirely.

>>1190059
if the outputs are for generic lab use then you should. alternatively get a PIC with an NCO in it and have lots and lots of frequencies.

>>1190063
How much work would it be to run an NCO without a µ-controller? Because if it's just a little binary through a PISO then it can't be too difficult.

>>1190071
a pic is a uc. there's no other through hole NCO/DDS options that i know of so if programming one sounds like a pain then i'd just stick with your current approach.

>>1190075
I can probably solder SMD if I have to, provided the pins aren't 0.2mm wide, which seems to be the case for everything out there. I guess I'll go with my current method. How would you recommend measuring frequency for an in-built display? I'd prefer it to work like a multimeter, which I guess means auto ranging.

>>1190088
the most junkbox-friendly way to do it is to use an edge detecting monostable multivibrator. it'll create a short pulse on each cycle of the input. as the frequency increases, the effective duty of the output increases, and filtering that output will result in a voltage that rises proportional to frequency. that approach is limited to a minimum frequency at which ripple isn't too high and a maximum frequency when the edge detector is being triggered prematurely. another analog solution is to use the LM29x7. in either case you'd read the value with a uc's adc (or one of those shitty adc-display driver combo chips for old meters).

for a digital approach use a counter ic to divide the frequency down low enough that you can get good resolution by counting the delay between input changes in a microcontroller.

>>1190096
Would you filter the output with a capacitor with a resistor across it? It should work if the input impedance of the ADC is significantly higher than the bleed resistance, but whether it would be linear or not I don't know. I'm wanting to be able to use a very large range of frequencies here (hence 8 shift registers), so I guess I could have some sort of manual ranging by switching between a couple of 1000x frequency dividers, assuming such things are readily available.

But at this point I think calculating the frequency from the number of divisions is going to be more accurate than anything done without a microcontroller.

>>1190102
you're correct on your second point. at first when you posted your circuit i thought you actually wanted a tapped frequency generator rather than a counter so i was a little confused. using shift registers is unnecessary though unless you're limited by what you have on hand. what you really want is a dedicated ripple counter. using a 74x161 followed by a 74x4020 will theoretically let you measure up to 100MHz (frontend necessary) and divide it down to a nice low frequency for a counter to work against (100MHz/2^(4+14) -> 380Hz).

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I made this arduino with a pic16f. Like it, /ohm/?

I'm going to use it as a controller for the exhaust fan in the room my cats use as a bathroom. It will have an RTC and three inputs: one is a toggle-switch, one is a regular tactile switch and the third one is a PIR sensor.

When the PIR sensor is triggered, the mcu will wait 3 minutes (it's the time a cat takes to take a shit and 2 more minutes) and then turn on the fan. When the tactile switch is triggered, it will turn on the fan for 5 minutes (this is the time it takes to purge the shit stench). When the toggle switch is on, it will blow the fan away. It will also turn the fan on for 3 minute every 10 minutes, unless it's night. During the night it will spin the fan for 1 minute every 30 minutes.

>>1190044
The output transition time is specified separately. It is around 20ns at 5V supply and 50pF load capacitance, increasing about 0.1ns/pF.

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>>1190108
I want a somewhat variable frequency generator. The multiple taps are there just to bypass the later shift registers, because if I want to get a frequency of, say 1MHz, each register will divide by two even if I'm only using one of their flip-flops. But on further inspection I could just bypass each register entirely by adding another input to the rotary switches, like pic related. I'll probably link two or three registers together (with one inverter across them) so I can get division by some of the higher primes, if I feel like linking two rotary switches together. If by "tapped" you mean I will be using multiple frequencies at once, then I probably won't.

What makes you think I want a ripple counter? To get the same performance as 8*8 bit registers I'd need 32 flip-flops. I know the actual efficiency per flip-flip is much higher for a "single bit register" or single flip-flop division, but for me it costs the same to get hold of 8 SIPO registers as only 8*dual JK flip-flops. If I just did want to get divisions by two then I might consider ordering 50-100 JK flip-flops online, but with registers I can get divisions by primes other than 2, allowing me much more range over which frequencies I want, rather than just as many as the flip-flops I bought. I'll write a program to figure out which settings I need to get what frequency, but that might take some time with my little programming knowledge.

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I have an incoming 4-5V range signal in my system i would like to amplify and offset to a 0-3V range. Also my power rail is 3.3V so i cant use any higher voltages.
I know an opamp should be used but i dont know how. Can anyone help me out?

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I'm looking for robust and simple way to plug in and unplug servos from a chassis. I've been thinking of using 3.5mm audio jacks having ring 2 as the signal, ring 1 as ground and the tip for power. Is this retarded?

I was looking at using d-sub 3 initially, but no one seems to sell d-sub 3 cable assemblies or breakout boards.

>>1190213
Not sure what type of servos do you use, they can go up to the kW power ranges, but im guessing yours isnt. Even then, jacks are not meant for power transfer.

Perhaps a "molex" type connector thats used in PC supplies, AMP has the name for it: mate-n-lok, not sure what Molex named theirs.
Also the PC motherboard power connection that Molex has: Ultra-Fit might be good too.

These should be cheap as shit.

>>1190216
Thanks for the reply, but I just found out that I am in fact a retard and the d-sub 3 connectors I want are available from a local supplier.

Programmer electrinics noob here with a couple of questions.

I was thinking about getting in to microcontrollers for a few projects, however the chip programmers are expensive as fucking ass, the question is how versityle are arduinos when it comes to being an universal JTAG(for cpld's), atmel or pic MCU or your average EEPROM(for propeller chips) programmer ? My reasoning is that i could get a programmer that could program for all of the chips i need for a price of one.

Another question is about raspberri pi or any other raspberry clone SBC DMA access speeds and if they could handle 3 or 4 camera(something like a ov7670) truevision 30fps byte wide pixel stream in realtime.
Im sure that the cpu could handle the image processing in real time more or less(even whithout the help of the GPU) but as far as i have researched the GPIO's seem to shit them selfs way before i would reach the bandwith of one camera at about 20MB/s.
So is there no way to squeeze in the data that i need to be processed from the cameras in real time ?
I could divert the stream in to a DRAM chip with a cpld but i doubt that a raspberry could fetch the data from it in such latency that i need.

>>1190223
Theres JTAGwhisperer that turns an arduino to a cpld/fpga programmer. Also you can program almost any atmel/avr with it i think even from the IDE. There might be a couple of pic programmers too, EEPROMS can be programmed too but you have to find implementations.

Id say go for it and when have settled with a device of your choice and need debugging capabilities or a dedicated programmer you can get one.

Purely theoretical question, if you had a 3hp+ electric motor and wanted to brake with it while running at max speed, could you PWM shorting the windings to have a gradual braking effect? Or would it be easier to PWM regenerative braking?

It's not really a theoretical question, I have a craving for starter motors on roller blades.

Red pill me on Deoxit. Is it the miracle cure everyone claims it to be for small repairs?

>>1190274
Depends what kind of motor. For a typical series wound motor just PWM shorting won't really work, the correct way to do it would be to apply a current to the field winding then PWM short the armature, or vice versa.

If you're providing a fixed armature current doing regenerative isn't too difficult either, assuming you're going with a buck converter like design for the controller, turn it into a half bridge, then it's a buck in one direction for acceleration, and a boost in the other direction for braking.

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>get a board made
>assemble it
>huh, why is my reference oscillating?
>double check TSM102 pinout
>mixed up which pins were an op amp and which were a comparator
i did it