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File: electronics for dogs.png (260 KB, 544x489)
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old thread: >>1303811

>I'm new to electronics, where to get started?
There are several good books and YouTube channels that are commonly recommended for beginners and those wanting to learn more, many with advanced techniques. The best way to get involved in electronics is just to make stuff. Don't be afraid to get your hands dirty.

>What books are there?
Beginner:
Getting Started in Electronics Forrest Mims III
Make: Electronics Charles Platt
How to Diagnose & Fix Everything Electronic Michael Jay Greier

Intermediate:
All New Electronics Self-Teaching Guide: Kybett, Boysen
Practical Electronics for Inventors: Paul Scherz and Simon Monk

Advanced:
The Art of Electronics by Paul Horowitz and Winfield Hill

>What YouTube channels are there?
mjlorton
paceworldwide
eevblog
EcProjects
greatscottlab
AfroTechMods
Photonvids
sdgelectronics
TheSignalPathBlog

>What websites feature electronics projects or ideas?
http://adafruit.com
http://instructables.com/tag/type-id/category-technology/
http://makezine.com/category/electronics/

>Where do I get components and lab equipment from?
ladyada.net/library/procure/hobbyist.html
Search the web for "hobbyist electronics sources" to find plenty.
In the US and elsewhere, mouser.com, digikey.com, arrow.com, newark.com are full-line distributors that entertain small orders.

>What circuit sim software do you use?
This mostly comes down to personal preference. These are the most common ones though:
NI Multisim
LTSpice
CircuitLab
iCircuit for Macs
CircuitJS (quick, dirty, interactive)

>What software should I use to layout boards?
Altium
CircuitMaker
Circuit Wizard
ExpressPCB
EAGLE
KiCad

>My circuit doesn't work. Halp?
Check wiring, soldering, part pinouts, and board artwork if applicable, then post schematic. Supply ALL relevant info and component values.when asking a question.
>Li+ batteries
Handle with extreme care, or... https://www.youtube.com/watch?v=gz3hCqjk4yc [Embed]
>>
Sorry, guys, can you explain to noob? This is oscilloscope specs. What is difference between "bandwidth" (100 MHz) and "bandwidth limit" (20 MHz)?
What signal frequencies i will be able to see with it?
>>
>>1310020
https://www.google.com/search?q=oscilloscope+bandwidth+limit
https://www.tek.com/blog/scope-tip-use-bandwidth-limiting-reduce-noise-captured-signals
>>
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>>1310023
Thanks, mister. Here is your kitty.
>>
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>>1309922
Thanks, faggot.
Oh, neat, this thread's digits brought to you in part by the HV9922 3-pin switch-mode LED driver IC.
>>
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BC414B x3
Metex hfe: 160 171 177
SM btest: 207 223 230
what the f
>>
>>1310165
Different measurement currents? Or maybe the other meter just sucks?
>>
>>1310165
That circuit looks a little too dependant on the transistor's hFE, but since you're tuning ti by hand anyway I guess it doesn't matter.
>>
Noob looking to buy assorted caps and other shit. Are these too cheap?
https://www.ebay.com/itm/540Pcs-24Value-Electrolytic-Capacitor-Assortment-Element-Pack-Box-Set-0-1-1000UF/
https://www.ebay.com/itm/1000pcs-50-Values-50V-Ceramic-Capacitor-Assorted-kit-Assortment-Set-Hot-Sale/151128848522
https://www.ebay.com/itm/50PCS-NE555P-NE555-DIP-8-SINGLE-BIPOLAR-TIMERS-IC-factory-price/141663371716

Also, what can film capactitors do that electrolytic/ceramic can't?
>>
>>1310172
>>1310174
The Metex has Ib=1.3µA. I calibrated the current source with a 600K resistor (600mV) before and after measurement. I don't trust the Metex.
>>
>>1310185
better stability for some applications.
also they can have high-ish capacitance like electrolytics, but be used for AC applications.
https://en.wikipedia.org/wiki/Film_capacitor#Applications
>>
>>1310165
what results are you getting with your current source calibrated to 1.3uA?

>>1310185
al-els is probably reasonable
not too cheap for the ceramics
555s maybe that's about right in quantity
>>
>>1310210
>what results
good idea
>>
>>1310210
1.3µA 780mV
270 298 302 mV
B 207 229 232
1M needs multi-turn..
>>
>>1310225
not sure if metex has weak batteries or weak metex
>>
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>>1310231
8.8V. The Metex has these horrible transistor sockets. I'll make me the SM pnp version.
>>
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It's time to upgrade from my shit $15 radioshack soldering iron. Should I really spend $100?
>>
>>1310251
No, not anymore. You can get a TS100 or one of its clones for $50-70 and it'll probably do everything you need it to.
If you want a better iron than that you would be spending more than $100.
>>
>>1310251
yes. they have replaceable parts. just make sure you dont get a clone.

>>1310259
enjoy getting a matching element or replacement parts when it dies.
>used to think this was a good idea
>get chink soldering station
>big and heavy
>rated at 60W
>open it up when it dies a year later
>has a transformer rated for 15W
gg
>>
>>1310263
>transformer rated for 15W
cool story
>>
>>1310251
After radioshack comes hobbyking
>>
>>1310251
aoyue seems to be among the better of the chinkshit. if you're amerifat you can get a 2 in 1 pencil/hot air 888A station for $75
>>
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>>1310266
>>
>>1310263
sheeeeeeiiiiiiit, half the chinkshits clones are based on Hakko parts anyway
>>
So I tried making a pickup for literally a bike brake cable tensioned with a bolt between two pieces of wood, pic related. Turns out pickups have 5,000-10,000 turns of wire on them, and I've probably only got 100-200. Hooking it up to an opamp and watching it with my scope and I only get mains buzz (the waveform goes away when I turn the gain down, so I know it's not coming from my $20 scope), which is obviously a product of having not enough turns.

Can I expect to get decent performance with a diy humbucker of similar style with less than 1000 turns, or should I just buy the cheapest chinese pickup I can and tank the shipping time? They all come in rows of 6 which isn't too helpful for me. I wanted to listen to something as shitty as possible to try and get some nice distortion, but at this rate it's a lost cause. Perhaps would I get results with a pre-made inductor with a magnet glued on top?
>>
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>>1310317
>>
>>1310131
That's a nice IC.
>>
>>1310318
>>1310317
that wire is enameled right?
>>
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I'm not sure if i'm getting the ULN2003 correctly.

On the input, I have a PIC, powered by 3.3V
The point is control the LEDs of the output (which use their own voltage source). Is this supposed to work just like pic related?
>>
>>1310317
there's a magnet in there, right?

>>1310337
leave CD+ open. otherwise, if I read the datasheet correctly, all the LEDs will always be on. besides, you don't have inductive loads, so don't need flyback diodes.
>>
>>1310336
>>1310361
Yes on both counts. The wire has an impedance of 8Ω so I know it's not a short from one side to the other. Can you even buy super-fine gauge non-insulated wire?
>>
evening /ohm/ if anybody can help me with a project. i have a few tools of my 'trade' that i'd like to modify. they all take wall power (240v in AUS i think) and i want to splice the main power cable and step it down so as to run MCU's, some sensors and maybe LED lights. im just trying to avoid using batteries really. cheers
>>
>>1310404
Wait, would more turns of wire even increase the signal:noise ratio to begin with? Wouldn't I just pick up the mains hum just as much stronger as the vibrating string signal? The wire itself is definitely steel, galvanised at that, and is attracted to the magnet itself when brought close. But I can only imagine that the problem is the weakness of the magnet, or perhaps the frequency response of the core. Perhaps I'll try running it off batteries outside far away from cables, to see if I can pick up anything. If not I'll try to power the solenoid to make its own stronger magnetic field with a current limiting resistor/constant current source so I can pick up changing voltage of the audio signal. I doubt that a filtration capacitor will help much, but I'll give it a shot.

>>1310407
A tiny toroidal transformer, a full-bridge, some appropriately-sized caps, and a (5V) voltage regulator is what I'd do. But a little flyback converter like what's in modern USB wall adapters would probably be better if you can sort that out.
>>
>>1310409
>signal:noise
A normal pickup focuses the magnetic flux at the vibrating string. More flux change, more signal.
>>
>>1310409
>flyback converter
https://www.ebay.com.au/itm/AU-Power-Supply-Adapter-Transformer-AC240V-To-DC-5V-1-2-3-4-5A-for-LED-Strip-3D/182936154591?hash=item2a97d831df:m:mMPUEorJyP9B8V72On55CbA

would this work, it would be abit chunky but i dont mind
>>
>>1310423
https://www.ebay.com.au/itm/AC-DC-100-240V-To-5V-2A-Buck-Converter-Isolated-Step-Down-Power-Supply-Module/332377573392?hash=item4d633f4810:g:gbAAAOSwFWVZmAH1
>>
>>1310404
>non-insulated
you don't want this. you want enamel wire.
according to the first ddg hit just now, 3.8km spools of 36awg can be had for about $30, which should supply for a lifetime of improvised instrument building
also, considered P-bass pickups? each one is made for two strings (4 poles) and you might be able to work them into a humbucking arrangement

>>1310409
humbuckers work by approximately the same principle as twisted pair. the fields of N poles on one coil and S poles on the other coil reinforce each other when a metal object in their field interacts with them. outside EMI that encounters both coils cancels itself out.
>>
>>1310419
Focuses? Any resources as to how that's done? Do they use those perpendicular magnet arrays?

>>1310428
I know I want it insulated, I was just wondering if you could even buy non-insulated 36ga wire in the first place. My wire is somewhere between 36 and 40, so I don't think I've got a problem there.

I understand how a humbucker works, but if my signal:noise ratio is still far too small then the tiny amount of differential noise from the humbucker setup may still be significant. Can I just surround myself in (grounded?) aluminium foil and see if it works enough as a faraday cage?

The magnet is at least 10 years old; I used it to try to make an electric motor for a primary school science thing at age 8 or so. It looked neat, but with only 10-20 turns in the middle there was no way it would have worked. Perhaps its age is why it isn't as strong as perhaps it should be.
>>
I've got a weird problem i noticed just today.
When i turn on my water boiler (in the kitchen) the light in the bathroom turns on (just a little).
Not like it bothers me that much that i waste a little energy on that lamp while i use the boiler, but what bothers me is that i have a gas-fired furnace right next to said boiler and i really don't want to get killed by explosion.
Right now i think i may have a notable voltage on the neutral wire due to some malfunction of the boiler which is connected to the houses tubing, but have no volt meter at hand.
What do?
>>
>>1310438
a stronger magnet will definitely help. that's what the coils are meant to be reading. but unless it's a horseshoe you're probably gonna need two
>>
>>1310473
get a voltmeter or hire a sparky
>>
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Hey guys I have a question, I am working on a project, that originally uses eeprom to save a text file onto. I want to add wifi, and thinking about adding esp8266, and I was wondering since it has 4mb of flash, is it possible to save text file onto that instead of using eeprom?
>>
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The Diode (D1) on the picture is from a JTAG connector.
The JTAG was connected in reverse and the only damage on the board was that diode only.
The diode is the RB751V40 and the datasheet is this one https://assets.nexperia.com/documents/data-sheet/RB751_SER.pdf

1st problem, can I just bypass the diode for the time being because ordering one SMD diode is not an option due to timing constrains(deadlines) or finding the same from left over boards is nearly impossible.
I have a dead laptop motherboard(the gpu is dead), where I can scavenge some diodes from.
I have found some JS (switching iirc) diodes and some 5D diodes, http://www.s-manuals.com/smd/js and http://www.s-manuals.com/smd/5d respectively, but since there is obviously no board schematic for the laptop motherboard I do not know what's the exact characteristics of each diode.
Can you suggest a quick fix.
Thank you in advance.
>>
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>>1310550
hey guess what jen flash IS eeprom!!
...basically.....kind of......
can esp8266 modify its own flash during runtime?
i don't know.
>>
>>1310685
>hey guess what jen flash IS eeprom!!
>...basically.....kind of......
>can esp8266 modify its own flash during runtime?
>i don't know.

why post this pile of shit? are you an asshole IRL too? or is this yet another example of "nerd humor"?
>>
Whats the consensus on sub-$60 power supplies? Should they be avoided?

Two options I found were 30V - 5/10A, the 5A supply boasts more features versus the 10A which just gives the greater output.
https://www.ebay.com/itm/30V-5A-Precision-Variable-Adjustable-Digital-DC-Power-Supply-Regulated-Lab-Grade/131179224846
https://www.ebay.com/itm/30V-10A-Adjustable-DC-Power-Supply-Precision-Variable-Dual-Digital-Lab-Test-110V/391321591608
>>
>>1310473
Sounds like a faulty neutral connection or ground loop. But I can only see this happening if the switch is an SPDT that switches the hot side of the light to neutral when not on; otherwise there shouldn't be any path to flow through to light the bulb. If you can't fix it yourself definitely get an electrician in, that could be the beginning of a house fire.
>>
>>1310679
sure, just remove it for now but make very sure you have JTAG connected up correctly next time

>>1310550
maybe, there's a little area of flash dedicated to user storage around 0x7C00 iirc
you could also repartition the flash and use something like SPIFFS in your user data section, start here, be bewildered, and search for more http://iot-bits.com/customizing-esp32-partitions-table/
>>
>>1310800
>sure, just remove it for now but make very sure you have JTAG connected up correctly next time
tnx man, I appreciate your help
>>
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>>1310750
>consensus
>mongolian fly fishing board
bruh
anyway, nothing much wrong with low cost bench supplies imo, though if you can stand the electrical noise those sub-$1 small 25x50cm step-up/down converters are nice to have handy and a fuckload cheaper.
I built the overcooked little mess in Pic related mostly to experiment with the bq24195 Li+ charger and power path chip (QFN24, left) and the LP3906 4-output smart regulator (right), solder paste stenciling, hot air reflow of a whole board, solder-bridging 0805s onto 1206 footprints, and KiCAD. looks like hell but works.
outputs: SYS 3.5-4.2V @2.1A with battery supplement, feeding ADJ 5-15V pot-adjustable @?mA, LDO1/2 1.0-3.5V @300mA, SW1 0.8-2.0V @1.5A, SW2 1.0-3.5V @1.5A, all digitally adjustable via I2C except for ADJ, and the next version probably will have that and a small uC for glitch testing
>>
>>1309922
Planning on using a raspberry pi 3 (christmas presant) to controll humidity, temp, lights\timer, water pumps and a camera.

Anyone know where i can buy the components and sensors cheaply in Scandinavia? Im having a hard time finding a supplier for basicly anything. My old street corner hobby shop has been gone for years and i dont have a single resistor left. Only got the tools.

Also what os should i go with. I havent programmed for years so im learning python again.

Thinking about Rasbian for os. Not familar with the raspberry at all so not sure.

>guess what im building
>>
>>1310854
Tempura machine?

Also read the OP, it has a "Where do I get components and lab equipment from?" section. Aliexpress is nice and cheap if you don't mind the lapse in quality.
>>
>>1310854
Growing imitation crab meat, are you?
no.farnell.com?
>>
>>1310854
raspi should be alright or even overkill, GPIO access is well-documented. you might want to implement a hardware watchdog of some sort just in case.
consider local electrical supply shops that cater to the trade but are open to the public. that is, if you don't mind being a notable person when people go around asking who's growing imitation crab meat in their shipping container. aliexpress may (or may not) be more anonymous in that regard. also if you go aliexpress, probably a good idea to derate claimed power handling capabilities by 25-50% across the board just so you don't set the shipping container on fire
>>
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>>1310859
>Also read the OP

Il give aliexpress a go. Was sad to see the hobby shop gone though. Was nice to have most of the stuff i needed a short walk away from my apartment.

>Tempura machine
Nope.

>>1310862
>Growing imitation crab meat
nope, lol.

Its going to be massive overkill what im building but im doing it to learn about all these new toys.

I will proabubly be posting alot about the project when im finished (or stuck).
>no.farnell.com
Nice, going to bookmark this aswell.
>>
>>1310866
>Growing imitation crab meat
Well ive been gone for too long. I guess it is imitation crab meat. (and other stuff)

>derate claimed power handling capabilities by 25-50%
>hardware watchdog
Good ideas

Know lots of local electricans so il ask around if they know about a shop that would give me the service.

The legal aspect is negible for me since im most likely not going to focus on imitation crab meat. Its mostly the designing & building im intrested in. What i produce is not that important desu.

Its going to be massive overkill since its basicly going to be a fancy box made out of glass\plexiglass etc. Ive noticed that the LED market has produced some amazing stuff so thats kind of the driving aspect.
>>
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i'm having some issues understanding something i feel like should be really a basic capacitor/voltage source analysis.
pic related is a pulse generator schematic from the 3rd edition of art of electronics (not exactly as shown in the book, but that isn't important)

when the circuit charges, C1 charges to roughly 4.4V. this makes complete sense to me. however, when Q1 becomes saturated, pulling C1 to ground, which discharges through R3. in the book, it says that at this point the base of Q2 goes to -4.4V. why? is it because an equivalent but opposite buildup occurs on the other plate of the capacitor? is it because when you look into the loop its just that the polarity is reversed? feeling like a brainlet
>>
>>1310821
Thanks for the input, the rest of the post just went over my head after you said converters.
>>
>>1310685
I didn't think so, I didn't mess with pic, mostly arduino

>>1310800
if I decide to go with just adding eeprom instead, can esp8266 access it via wifi? It might be stupid question since its could be a common thing to do, and I don't mean eeprom on 8266, if there is one.
>>
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>>1310951
heh, sorry, get a half dozen of each of these step-up and step-down converters, then just get a big 12V power supply at 5A or so to feed them all

>>1310969
I imagine you could customize SPIFFS to use any device of your choice, or use some FAT library out there
>access it with wifi
setting up an HTTP server shouldn't be too hard, there might already be some code for this out there. how it responds to requests is of course up to you, from just dumping text/plain or whatever to the socket on up to dynamic on-the-fly HTML formatting.
it's all just a matter of wiring it all together
>>
>>1310950
Because the sine goes from +5V to -5V, not from +5V to 0V. I think.
>>
>>1310950

the LHS of the cap is 4.4V more positive than the RHS. so when you force it to 0V, the other side as no choice than to become -4.4V because the charge is still there (until it starts to dissipate) but the reference point has shifted. it's like when you're reaching for a croissant, and suddenly the earth moves 3 feet to the right. you're gonna miss it by 3 feet and get laughed at by your co-workers.
>>
>>1310981
>>1310986
thanks you guys, after doing it out a bit more i came to a similar conclusion about the reference point but the confirmation is much appreciated.

i could really go for a croissant
>>
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Can someone help with wiring. I have a power supply and a AC heater for a 3d printer. I can wire them both to a single power cord going to an electric socket right? Since they have different resistance the circuits will draw different, appropriate current and my power supply or controller won't explode? Pic related.
>>
>>1311007

you're missing some crucial information
- what's the power supply expect as an input voltage?
- what's the heater expecting as an input voltage?

if both are expecting 120V, then there's no problem, they will each take as much current as they need, and all will be right in the world.
it'll be exactly the same as if they had separate power cords.
>>
>>1310978
Ok thank you for the help (anon asking about esp8266)
>>
>>1311016
>- what's the power supply expect as an input voltage?
>- what's the heater expecting as an input voltage?
Both AC 120V. It's an AC to DC LED power supply and a AC heater.
>>
Bought a servo and some other shit for a school project. Servo's got three wires. Net says one of them is for the 'signal'. Hooking the servo up to the power doesn't seem to do much. Do I really need a microchip (or some other way to provide a constant signal) to operate the damn thing?
I have zero experience with electronics.
>>
>>1311044
Yes. That's the point of a servo: to position itself according to a signal.
If you wanted a motor you should have just gotten a motor with gearbox.
Search the web for "555 pwm" for inspiration.
>>
>>1311046
Thank you, my anonymous hero.
>>
>>1309922
what does ∋ mean in
B=µ0*∋
>>
In what cases should you use a pnp bjt over an npn?
>>
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>>1311367
When it is more convenient. For example, shit referenced to the positive supply might be easier to design with PNPs.
>>
>>1311371
Thanks
>>
>>1310950
>>1310986
Incidentally this is why charge pumps and voltage multipliers can work. You're storing energy in the electric field, even though you've changed your reference you already have accumulated charge on the capacitor.
>>
>>1311367
not just PNP BJTs but PMOS are frequently used for high side drivers/switches.

It's harder to drive highside with N type silicon because it requires a control voltage that is typically higher than what is coming out of the device which means you need a charge pump.
>>
I want to get back at a shitty business, can I spam the fuck out their phone lines with arduinos and GSM shields?
>>
>>1311378
Look at the image at >>1310238
>>
>>1311578
maybe, but, why not sit on their network, and try to find anything shady on them, and report it to the news. Find something good, and journalist will keep pushing on the company.

Then again that is probably just in tv shows.

Just find accounts, and drain them.
>>
does anyone know what wattage of current sensing resistors do laptop batteries use? i burnt one 0.05 ohm resistor, and besides resistance i only know its packaging, as its 2512 smd resitor. on aliexpress there are 1, 2 and 3w resistors but the 2 and 3w ones are too expensive
also, whats the difference between a current sense resistor and a regular resistor with small resistance value?
>>
>>1311679
>what wattage
What power you mean, otherwise you would have asked..
>small ohmage value
Anyway all you have to do is calculate the power dissipated, you know the resistance value so you either need the current through it or the voltage across it.
Here is a tip: The voltage across it might be the battery voltage?
So power = voltage x current and current = voltage / resistance so power = voltage^2/resistance. That's the minimum power rating you need, ideally x 1.5~2 for safety.
There is nothing special about a sense resistor, resistor has a resistance, tolerance, power dissipation, match them and you are golden. But a sense resistor must be part of some tuned network? You will have to match the actual value, not its nominal value
>>
>>1311716
well since it literally caught on fire and partially melted i can't really measure anything, i did manage to identify it by a notch in one corner (which i saw other resistors have) and by some remains of the writing which gave away the 50mOHM. the voltage of the battery is 11.1v, but i'm not sure on how should i find out the resistor's power, there are 1w, 2w and 3w resistors for me to choose but the 3w ones are 20+$ a lot which i really can't afford for a 2000's laptop battery repair
>>
>>1311716
>ohmage
>Here is a tip: The voltage across it might be the battery voltage?
Go troll somewhere else.
>>
If you had a flat piece of np silicon and a beta source pointed at the n side, can you make electricity flow assuming the p side is connected to ground?
>>
I want to do embedded programming and really low level electronics stuff with computers
a dream of mine is to hand-build a computer.

I see stuff like the nibbler, BMOW, and the 68 Katy and it fascinates me. What all do I need to study to actually be able to do things like this?

>inb4 if you have to ask you can't do it
I know, that's why I'm asking for resources/fields to study in
>>
>>1311792
alright, what is the textbook for Computer Design?
There's SICP for programming,
Modern Operating Systems for OS development,
The Art of Electronics for EE,
so what is The Big Book for Computer Design/Engineering?
>>
>>1311788
https://en.wikipedia.org/wiki/Betavoltaic_device

>>1311792
Dunno. I have Logic and computer design fundamentals, by Mano and Kime. It isn't that great. Then there's http://nand2tetris.org , which is at least quite well-known.
>>
>>1311792
Take mit 6002x online course. It's worth it, you'll go from knowing jack shit to having a real foundation which you can build on.
Read anything and everything you can get your hands on to do with electronics.
Read The Art of Electronics, read the Circuit Designer's Companion, read a real electronics text book (the companion textbook to 6002x is free online)
Might as well read the schematics for the 68katy, and the datasheet for a motorola 68k processor while you're at it.

>>1311803
I'm not aware of the bible for computer design, but these are relevant:
High Speed Digital Design
Electromagnetic Compatibility Engineering
Computer Architecture: A Quantitative Approach
I don't own the last one but I skimmed thru the pages on amazon and it's relevant to processor design.
>>
>>1311728
To size your device correctly you need to know the maximum sustained current the laptop battery will use.
Suppose it's 6 amps (arbitrary guess) then you do P=I^2*R which 6*6*0.05 = 1.8W and thus you'd need a 2W resistor to replace it.
I have no idea what your situation is though.
Maybe check on mouser or DK for a 2512 50mOhm resistor, $20 seems absurdly expensive
>>
>>1311836
thanks, i'll try there
can i, for example, buy a 3w one just to be sure? im pretty sure 2 or even 1w will do because laptop charger is rated at 4A
>>
>>1311862
>can i, for example, buy a 3w one just to be sure?
Yes
>>
I'm extremely interested in analog video signals. Are there any good resources on the topic?
>>
>>1311803
When I did embedded required reading was ' structured computer organization' by tanenbaum. Never forget his name because its German for Christmas tree?
Don't ask me if its any good or what it's about because I never fucking read it it was like £60 I'm not fucking made of money m8.
>>
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>>1309922
Can solenoids handle constant power?

I have a solenoid from an old starting motor that still actuates and I wanted to pull it and use it for stuff. I am concerned that hours of being turned on will damage it or cause it to fail. Can these things handle being turned on for hours at a time?
>>
>>1311679
Sometimes current sense resistors may have Kelvin sensing connections. If this is the 50mohm resistor that burnt up several weeks ago on here, I think it was just a regular 50mohm resistor with the Kelvin sensing connection done at the board level instead.

>>1311803
>>1311826
>Computer Architecture: A Quantitative Approach
This one is the bible for computer design. There's a complementary book by the same authors, Computer Organization and Design, which I have not read but will someday.
I would suggest starting by reading up on everything you can about the PDP-5, which is probably the simplest reasonably useful processor. Doing so will give you an idea of what holes there are in your knowledge of the basics. You'll need to know digital logic, particularly finite state machines and other sequential logic. Understand data structures and how they relate to individual bits/bytes in memory.
Maybe you'd even want to learn an HDL so that you can experiment and prototype more easily than with interminable wire-wrapping or worse, and so you could look to picoBlaze and other simple processor cores for architectural inspiration. At that point you'd probably be ready to attack the Hennessy books.
Since you didn't say where you were starting from, I can't give better recommendations.

>>1311938
Not much to know about them. Timing is handled pretty much the same way across the three main standards NTSC/PAL/SECAM, and only the chroma information is much different. Wikipedia's technical overviews and a bit of trial and error are sufficient to produce an implementation.
Old National Semiconductor app notes are always worth the read.

>>1311948
That depends entirely on the solenoid. Read the datasheet.
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>>1309922
Just got a copy of Make: Electronics and when skimming through I saw that the author recommends using a universal adapter such as pic related as a power supply.
Since these things are designed to be used with safety tested electronic devices and not by some autist sticking wires together on a breadboard, I'm wondering how safe it is.
What would happen if I accidentally end up short circuiting, overloading etc.?
Also, if it is safe, then what's the point in paying 6x the price for a bench supply?
>>
>>1311950
Any idea how safe it is to play around with analog video signals? Can I kill a CRT by sending it garbage?
>>
>>1311971
As long as you keep the voltages and frequencies sensible you should be fine.
>>
>>1311950
>Read the datasheet.
Ill have to actually pull it out. All I know about it at this point is when current is applied it will jump out.
I guess I should have used the word "generally" in my question
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>>1311969
I've had good luck with the one I use. Some hosa $10 POS. If I ever short anything out, the supply shuts down and comes back up as soon as the short is removed. It has a little green light to tell me if it's working, and the light goes off when shorted. I would like a bench supply, though. Easier to work with, imo.
>>
>>1311971
Should be safe as long as you stay within 1Vp-p and don't send anything particularly pathological. Those circuits were relatively robust. otoh probably not very much fun unless you have some sort of sync generator.

>>1311983
Generally, no, but some are. Usually they are designed to a particular maximum duty cycle and/or on-time, as longer duty cycles have to be more mechanically robust and provide for greater heat-sinking.

>>1311969
Bench supplies provide more current adjustable current limiting, more precise voltage adjustment, possibly better voltage regulation, possibly cleaner and stiffer power, and a nice box. Sometimes it's worth the money, depending on what you're doing and how often.
>>
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10w 12v to 200v flyback converter
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>>1312024
interesting silkscreen numbering scheme
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>>1312028
i find reference designators to be really annoying. i just have the values in a table on the back of the board, along with a helpful + for gnd and - for vdd. good thing uc3842s are cheap.
>>
>>1312015
>generally no .. more mechanically robust and provide for greater heat-sinking.
thats what I suspected, thanks for the info
>>
>>1312032
there is something to be said for just saying fuck it and printing up a 2x paper copy of a layout with references on it, esp. when they get long bc of a design spanning multiple sheets. it's not too bad as a stuffing aid, either, but I can see advantages and disadvantages to having your BoM right on the back of the board
>>
Does circuit simulation software let you emulate chips?
>>
>>1312082
If you mean a complex digital chip: no, you need Verilog/VHDL sources for the chip and the appropriate simulator.
>>
>>1312082
Do chips let you emulate circuit simulation software?
>>
>>1312082
yes
>>1312108
no
>>
>>1311938
This actually seems (theoretically) way easier than I thought it'd be. Going to try to rig up composite video output for this TI evaluation board that I have no idea what to do with. Hopefully my CRT doesn't explode, it's the only one I have.
>>
>>1311948

some can, some cant. it all boils down to heat. for example, the ones that keep a building's door open in the day and locked during the night may be on for 8 hours straight. so they'll have lots of metal to dissipate heat. nonetheless, the few that i've taken apart all have brown-ed insulation meaning one day soon they'll fail.

so one way to test it is to run it continuously and keep an eye on the temp. if you can hold your finger on the coil for 10 secs, it should be ok.
>>
I can't find any resources that specifically address this, but just to be clear, a component signal like YPbPr still just follows the normal NTSC specification, right? The only difference is that the individual components (however those are defined for the specific component type) are extracted from one another?
>>
quick question, I bought a usb led light for my arcade machine marquee but its too bright, was just thinking of putting a potentiometer in it to restrict the voltage, would this work alone or do I need other components, I want to restrict the voltage not increase it.
>>
>>1312168
>putting a potentiometer in it to restrict the voltage, would this work alone
It's more than enough.
>>
>>1312168
If it's pulling less than 100mA then go for it. I'd just use a trimpot so you can just adjust it with a screwdriver on the PCB, instead of having to panel-mount something.
>>
>>1312168
a pot would work, check power rating first. you could also make use of the inverse square law and just set it back a few inches
t.studio photographer

>>1312149
modulo the timing difference between standards, basically, yes
>>
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if i attach wires from pic related
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>>1312186
to pic related, will achieve the results im looking for, that is, when motor is activated by an already wired up button the 5v will turn on and give me usb power?
>>
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>>1312186
>>1312187
actually, while im at it im waiting on some 4.8mm connectors but i was wondering if this piece is also a terminal or just a piece of copper?
>>
>>1312186
Measure the voltages. If one of those is a neutral (blue?) then blue to black or blue to brown should be 240VAC, but you should measure the voltages. GND should not have current flowing through it and isn't needed for the double-insulated 5V adapter. Also that better be able to charge at least 2A.

>>1312188
It might be for wiring it up at a different voltage, in which case it's hooked up to the windings.
>>
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>>1312191
this one is around 1.5A i think surprisingly enough i didnt have alot of 2A laying around so i wanted to break one of these open instead to try first.

>Measure the voltages
ill get right on that i dont really have a meter that will survive this task though so im in the market for one.

>GND should not have current flowing through it and isn't needed for the double-insulated 5V adapter
thank you very much for that

>It might be for wiring it up at a different voltage, in which case it's hooked up to the windings.
thanks for the insight.

ill report back once i've riced it.
>>
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I tried to design a circuit with Logisim that could control several traffic lights with two common "data" and "clock" signal lines.
The circuit turned out to be really complicated. After all, I managed to simulate it with a single 4017 counter, 74hc164 shift register, two JK flip-flops + several XOR/AND/OR/NOT gates.
>>
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>>1312511
Here is my test circuit. With three address bits I can control 8 lights. "sel" output tells if the traffic light is currently selected (its address was received from the bus). "rdy" output tells if the controller is at the beginning of its operating cycle, i.e. ready to receive address bits.
>>
>>1312201
Any basement-tier multimeter can handle 240VAC, including my $2.50 analogue meter. I wouldn't try it though.
>>
>>1312511
74HC164s are a staple of anything digital. I bought 50 and I'll probably end up using them all. 74HC595s are also good since they have a latching feature, if you want to multiplex something like a display manually.
>>
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Can someone help explain this wiring for an air pump hooked up to a micro controller? Does installing the diode across the load literally mean wiring the +12V in and the ground out to the motor, and also bridging the wires with the diode like in figure 2 or does it just mean put the diode between ground out and the 12V input like in figure 1?
>>
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>>1312596
figure 2 is correct. the reason for the diode is that the motor stores a small amount of magnetic energy that needs to be dissipated when it's turned off. the diode just gives it a path to discharge as in pic. without the diode the energy results in a very high voltage briefly after turnoff which can fry your circuit.

in figure 1 the diode will prevent current from flowing through the windings by presenting a very high impedance (when reverse biased). if you reversed the diode it would do nothing but waste power.
>>
>>1312596
do it like figure 2, motor and diode in parallel
motors act like an inductor, they want to oppose any change in current. when you power off the motor the magnetic field collapses and the current gets dumped, but there is nowhere for it to go because no circuit so there is a huge voltage generated or something. thats the point of the diode, to short out the big spike from the collapsing field. if you think about the motor as a battery producing the voltage and the diode shorting it out in reverse it should make sense. kind of.
google back emf for info its well documented.
>>
>>1312600
Oh I see, I didn't even know the motor would discharge like that after turning off. Very neat. thanks my friend.
>>
>>1311022
Yes, you can wire them together.
All loads are wired in parallel across the AC mains. The voltage is always constant, each load will draw the current it's rated for.
>>
>>1312168

the 3 people suggesting you use a pot have probably never tried it, and thus havent smelt the results of doing so. pots are not meant to carry any significant current unless they're large, heavy, and expensive wire-wound pots.

a small fixed power resistor is best. second-best are diodes: use one in series to get some dimming, two for more, and three for romantic tête-à-têtes between yourself and your machine.
>>
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>>1312511
bretty gud. three notes:
1. synchronization. you should really add a start bit. in your design you can just hold the 4017 in reset using a clocked JKFF with din on J and the word complete signal on K. then you can prevent loss of word sync with a start bit by just keeping the clock running with 0 data between words. bonus: supply a stable, accurate bit clock and inverter, and you now have a cheap flaky UAR and can control the circuit from your favorite USB-TTL-serial dongle by sending single characters. in this case I advise you use the two remaining bits in the byte as fixed check bits so that you can detect and ignore bad packets which will occasionally happen as your bit clock slips out of phase with the host.
2. synchronous logic: when you get into large or high-speed logic designs it's a good idea to distribute the same clock to all your registers and set the next cycle's inputs up for them (including enables), instead of producing a clock as a function of layers of other logic. more predictable, less chance for glitches and races. if you must, one good way is to delay by half a cycle using a DFF with an inverted-phase clock (see Pic related, taken during a non-matching address)
3. those sel and rdy outputs are costing you the ability to take a more combinatorial approach: read the whole word into the shift reg at once, check the address, and gate the output (or not) accordingly. you could then also use the aforementioned start bit to time the word and reset the circuit. these aren't real standard 7400 series parts but it shouldn't take more than minor adjustments to get there.
4. also you can use the plexers to generate your test words for you rather than manual keying.
>>
>>1312723
A trimpot should be able to pass 20mA easily at 3V or so. But if it uses the full 2A then definitely not.
>>
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Can anybody identify or find a datasheet for this part (the one in the to92 package)
>>
What's the cheapest piece of hardware for converting mains power into low voltage DC?
>>
>>1313035
chinese usb charger from ebay for $1-2
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>>1313041
makes sense, thanks
>>
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Hi, guys. What cons in making vacuum cleaner robot motion on stepper motors?
>>
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>hook up two dc motors, two LDRs, an ultrasonic sensor and a servo motor to an arduino
>these things are supposed to work together
>can't get the code to work but whatever
>cause
>suddenly the one dc motor begins to spin whenever i plug the arduino in
>it does this no matter what i upload to the arduino
>haven't touched any wire at all
>it just suddenly does this
why?
>>
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>>1313035
If you want to build one yourself, simplest circuit is pic related (you probably want to add a fuse to limit the current).
>>
>>1313049
could be you inadvertently fried something while bungling around with code, due to you miswiring something.
if you can't get your code to work start from the basics... then don't assemble everything together at once, do one piece of hardware at a time.
could be anything that went wrong, need more information + pics. try swapping the dc motors. try running your code and testing the gpios for correct operation without all those gewgaws and do-dads plugged in.
>>
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Can you guys help me identify this condenser?
>>
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>>1313088
Here is the motor it is attached to if that's any help.
>>
>>1313088
it looks like a CBB60 rated for 400 volts AC 50 hertz

most of those are rated for 450 volts

if you need a new one google CBB60 and find one that works
>>
>>1313097
The problem is to find the one with the right capacity. Its not printed on this one so I don't know which one to choose. Could something go really wrong if I choose on with too high capacity?
>>
Please Help me /diy/ Where do I even get started with learning electronics? it really interests me but I have never found any good learning sources.
Should I just start with how to diagnose and Fix everything electronic? any other good sources ?
>>
>>1313154
>I have never found any good learning sources.
Try these free online courses that teach the fundamentals.
The book for this is available online for free when you sign up:
https://www.edx.org/course/circuits-electronics-1-basic-circuit-mitx-6-002-1x-0
https://www.khanacademy.org/science/electrical-engineering
Online web book:
https://www.allaboutcircuits.com/textbook/
There aren't any shortcuts... if you don't learn the fundamentals you're going to be fucked.

>Should I just start with how to diagnose and Fix everything electronic?
I own that book, it won't teach you electronics but you'll learn a few things.
>>
>>1313055
>could be you inadvertently fried something while bungling around with code, due to you miswiring something.
>if you can't get your code to work start from the basics... then don't assemble everything together at once, do one piece of hardware at a time.
might be i fried something because i assembled everything before and it of course didn't work as i wanted it too, but each part still worked apart
>>
>>1313187
>dc motor
Did you put back-EMF diodes across each one? If not, you probably blew your microcontroller.
>>
>>1313154
that book is wrote by a technician and not an engineer, if you master the fundamentals posted by >>1313167 you should be on par with a recent grad engineer, and by default with practice you should understand and explain on detail most of what any technician does
>>
>>1313099
>Its not printed on this one so I don't know which one to choose
It's probably just faded/rubbed off.
Hold it under a strong light and adjust the angle between the light, the cap, and your eye to see if you can locate it.
Yes, it needs to be the correct size.
There is a formula for the intended voltage vs the winding resistance or the specified current rating somewhere but I'm not sure what it is.
Google with terms like 'find correct motor capacitor' or similar.
Perhaps someone who knows the formula will notice your post.
>>
>>1313354
Well if it's just a start capacitor then you can make some estimations and you'll be fine, but if it's a run capacitor you should definitely search for the correct value.
>>
>>1313050
That might be good practice, thank you
>>
>>1313410
If you do use it, a linear regulator might be a good idea if you need a very stable voltage at less than a few amps.
>>
>>1313204
That might be it
But i forgot to mention that i used a L293D
>>
>>1313354
>>1313377
>It's probably just faded/rubbed off.
Unreadable for my eyes, no matter how hard I stare at it.
>it's just a start capacitor
I think it is, I can 'start' the motor manually by turning the shaft when its on, so I sould be just fine if I am a little bit off.
>>
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How do i know if an ESC is compatible with my motor choice?

Here is my chosen motor:
hobbyking. com/en_us/turnigy-aerodrive-sk3-6374-192kv-brushless-outrunner-motor.html

This is my chosen ESC:
hobbyking. com/en_us/turnigy-ae-80a-brushless-esc.html

They'll be used for an electric bicycle conversion. I have no idea which specs need to match to check for compatibility other than voltage and current, which both seem to be fine to me.
>>
>>1313531
it looks like your motor is 12s and your esc is 6s. am i missing something?
>>
>>1313540
what is 's' here?
>>
>>1313541
lion cell count. 12*3.7v or 6*3.7v nominal respectively.
>>
>>1313545
Ah, I see, thank you.

So my motor and ESC are incompatible?
>>
>>1313557
strictly, yes. you can run the motor at lower voltages but the motor current limit is the same so you're just missing out. disclaimer: not a dronefag
>>
>>1313545
>>1313540

Under voltage it refers to Lipoly, using 10-12S Lipoly or 2-4S Lipoly.

Does Lipoly literally just mean 3.7V?
Voltage in series is summed, so 12*3.7 = 44.4V, i.e. a 44V motor? No?
>>
>>1313560
lion and lipo are roughly the same voltage. peak is 4.2v, nominal is 3.7v, discharge should be stopped at 3v or slightly under.
>>
>>1313563
>>1313545
Thank you.
Why dont these sites just list actual voltages instead of giving cell configurations?
>>
>>1313568
"volts" is that dangerous thing that comes out of the wall. best to keep things simple for the braindead students that want to make a gopro drone for their senior project.
>>
>>1313571
Lol
Im an electronic engineering student and trying to decipher their voltage system was beyond me. Seems like just a plain bad idea desu
>>
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Hey guys, I would like work on a project to prank a friend of mine, I was thinking of doing some sort of random keystrokes at random times, or whatever he types is not what will be displayed on the screen . I took a look of hid emulator using arduino pro micro or at least one with a ATmega32u4 chip.

I was curious, if I want to shrinkify my project to PIC microcontroller, what features would I need to look into so I can emulate a keyboard? i2c? interrupts low-to-high/high-to-low? (I am aware of teensy) He has a usb keyboard.

this may sound stupid, but if I de solder micro nano usb and put usb 2.0 that won't make a difference as long as wiring is hooked up correctly.
>>
What Kind of supply do I need if I want to let 2 Amps flow trough a low ohmic load (<2Ohm). Do I need a lab supply for this or is there a option that need less space? Something portable would be ideal, but I can live without that.
>>
>>1313473
>I can 'start' the motor manually by turning the shaft when its on,
Run capacitors act like this too.
>>
>>1313592
Just shitting out random keystrokes: you need just a USB-enabled microcontroller and whatever it needs to run. Typically this means a suitable crystal and possibly a regulator. The thing in your picture is pretty close.
Modifying the keystrokes: the same device has to function as both USB master and slave and you have to plug the keyboard in it. Easier alternative would be that your random shitter device also sends randomly backspaces. Or you might want to implement the whole thing in (PC) software.

There's no difference between micro-B, mini-B and normal big B connector usage. Just wire them correctly.
>>
>>1313600
you can use two LM317s in parallel as current sources and any 5.5v+ supply. the closer the supply is to 5.5v, the less heatsinking you need.
>>
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>>1313473
Start capacitors are usually of a high value and are taken out of the circuit once the motor starts.
This is generally done with a centrifugal switch inside the motor.
On sealed motors (refrigerant compressors) switching is done externally by relays or electronic devices.
If your motor makes a 'click' noise as it is spinning down when turned off, it is the internal switch making the noise.
If there is no click, it's likely a run capacitor which is designed to stay in the circuit.
The value of the run capacitor is important.
>Single phase electric motors need a capacitor to energize a second phase winding. This is why sizing is so critical. If the wrong run capacitor is installed, the motor will not have an even magnetic field. This will cause the rotor to hesitate at those spots
that are uneven. This hesitation will cause the motor to become noisy, increase energy consumption, cause performance to drop, and cause the motor to overheat.
>>
>>1313606
I was in a hurry for splatoon 2 splatfest, and forgot to mention that I would be using a usb host mini on this project, too. And what do you mean by suitable crystal? a chip? Software might be easier, but getting i on his pc is one thing. All I would have to do for quick one, is change keyboard loadout.

thanks for the help
>>
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>>1312749
First of all, thanks a lot for the detailed comments. At the beginning I tried to implement the circuit with just CD4017 counters and D flip-flops but could not find a way to make it work. I see the CD4017 used almost exclusively in blinking lights applications and I wanted to explore other ways to use it.

Even though I did not understand a lot, I managed to simplify the circuit somewhat and add your suggested start bit with a JK flip-flop. The "start bit" JK now resets the counter and the shift register. The 4017 now just provides the clock signal for the output D flip-flops and reset signal for the start bit JK.

>it's a good idea to distribute the same clock to all your registers ... instead of producing a clock as a function of layers of other logic
If I understand correctly: it would be better not to rely on the CD4017 to provide the clock signal for the output D FFs?
>>
I have some graphite spray used for coating CRT tubes. Can i use this for RF shielding on plastic cases?
>>
Bought a "goot" soldering iron, made in japan. Is it a good one? I'm tired of shitty Chinese ones that don't get very hot.
>>
>>1313691
*CRTs
>>
>>1313698
I have a cheap KX-40 and can't complain. Shit gets hot like it is really 40 W (unlike no brand shit) and spare parts are available in case you break the heater or need a new tip.
I frankly don't know how goot is not as shilled as weller or hakko around here.
>>
>>1313691
You may have noticed that the inside of some plastic laptop cases are metallized... looks like a light dusting of shiny metal particles, and this is for electromagnetic compatibility.
So yes graphite will work, but look at: http://www.thermospray.com/faqs/EMIRFI.html
Graphite works but copper or silver are better.
>>
>>1313600
Is this for a mouth fedora (e-cig?)
>>1313607
Or use one LM350, good for 3 amps.
>>
>>1313605
>>1313621
Thanks for the info. Today a got a 20 uF CBB60 and installed it. The motor runs, when I get the equipment to test the motors energy consumption I'll test it and report back.
>>
>>1313834
It would also be good to know if it's a start capacitor or run capacitor.
>>
>>1313847
Well according to >>1313621 picture, which says run capacitors have commonly lower uF I think I have a run capacitor. If size matters. The original capacitor is as big as the one I bought.
>>
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>>1313592
you'd want a PIC micro that has an actual USB engine in it.
you probably don't even want to try bit-banging USB on a PIC micro.
but really you'd probably just want an ATTINY with V-USB firmware

>>1313600
generally, almost any adjustable voltage reg can be coaxed into serving as a current source. simply replace the upper resistor of the adjustment divider with your load and the lower with a resistance that yields the particular device's specified feedback voltage at the desired current (note, for high-side three-terminal regulator ICs it's the other way around). look to constant current drivers for LEDs for the gist of it
if you want the whole thing put together, search aliexpress for constant current power supply modules, like Pic related.

>>1313686
>not to rely on the CD4017
the CD4017, being based on a Johnson counter, is probably one of the better devices for directly clocking other logic. if you were doing something like decoding a binary counter or other inputs of varying propagation delays, you'd probably want to consider synchronous design, i.e. calculating for the next clock step ahead. I would trust your design in production

>>1313698
ees berry goot
srsly tho it seems like decent low-end stuff
>>
>>1313698
Well I had a non temperature controlled 40W model and it broke in much less than 1 year, but that's probably just because its not temperature controlled. Still, my cheap 30W Chinese iron lasted a good deal longer. Moral of the story being, get something temperature controlled.
>>
>>1313922
But it's not like I can't just buy a replacement element for it.
>>
>>1313606
>Just shitting out random keystrokes: you need just a USB-enabled microcontroller and whatever it needs to run.
No, you can use controllers w/o integrated USB controllers. And no xtal is needed.

http://macetech.com/blog/?q=node/46
>>
>>1313568
>Why dont these sites just list actual voltages instead of giving cell configurations?
Because all batteries aren't true voltage sources, voltage drops as the battery discharges. The usable voltage range depends on cell construction/chemistry. It's easier to specify cell type and battery configuration. For both users and sellers.
>>
>>1312909
The pic is too blurry. Take a decent pic plz
>>
>>1313917

This fag responding >>1313592

thanks for the reply, while I was on break at work, I came across attiny, and v-usb firmware. I will do more research on that, thanks!
>>
>>1313941
Not on a PIC
>>
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>>1310263
>>1310259
>>1310251

I can not praise the ts100 enough
i had a "cheap" 40$ generic digital soldering station before and sold it because the Ts 100 was shilled on youtube by a few of my favourite youtubers

My god this thing is sooooo much fun to work with its amazing
and in the rare cases you have to solder something outside you can just plug in a 3s lipo

A M A Z I N G
M
A
Z
I
N
G
>>
>>1314043
>it's not ESD safe
that's what this is for. if you're finding yourself needing to randomly repair broken wires, you just wrap some solder around the splice and heat it.
>>
>>1314050
its optional but if you need it no problem thats what the top screw is for
>>
Anyone here using qucs? Any vhdl file I throw at it gives me a segfault back. I just save it as something.vhdl in the project, and then simulate the file.
I used the testbench from the qucs docs pdf where they explain how to do digital simulations, so I don't think something is wrong with the file.

https://pastebin.com/PS6zQUT6

Can anyone help?
>>
>>1314054
Ditch vhdl, switch to Verilog or SystemVerilog.
>>
>>1314058
Why? I didn't look into it, sounded kind of proprietary so I just took vhdl, what makes verilog better?
>>
>>1313768
>>Is this for a mouth fedora?
Nope, art project with nitinol wire.
>>
>>1314043
When I ordered mine, I thought I was falling for a meme but figured it was cheap enough that I could take that risk.
but it's pretty great, does everything I need it to do, I have never found it underpowered like some people said it is, and unlike my old Weller, it'll run on a battery pack.
the future is now. something that tiny and that cheap actually can be decent now.
>>
>>1314060
> what makes verilog better

Much less verbose, much easier to use and learn. However you have to be more careful while coding.

You can use gtkwave and icarus verilog, for example.
>>
How hard is building your own inductance meter? Dont have any at hand at the local store and cant wait for a chinese one.
>>
>>1314054
qucs uses freehdl which I think is basically a dead project (last update was 2-3 years ago). About opensource vhdl simulators I had more luck with ghdl.
>>
>>1314103
>>1314072
Thanks, I will try both. Seemed like a good idea to simulate the vhdl and be able to add discrete components visually too, but I guess it wasn't meant to be.
>>
Can anyone recommend a good 4 or 8 bit binary counter?
>>
>>1314185
up/down? output preloading? just search "counter" in the lists of 7400 and 4000 series logic. there's a dozen of them.
>>
>>1314187
I am just getting into this stuff and I’m not really sure what all of that means (sorry) but I was planning on using it in tandem with a 4511 i had lying around to drive a 7-segment display
>>
>>1314193
those things i mentioned are just bonus features. for a 4511 you'll want a BCD counter. BCD is just 4 bit binary that's only allowed to go to 0b1010 (dec 10). you can use a 4510 or a 4518 in the 4000 series.
>>
>>1314203
Thank you
>>
>>1313740
I tried out graphite, it was pretty messy and smeared off easily. Then i applied plastic spray over it and it was okay.
Best thing one, the two halfs of the case that i coated were electrically connected this way
Best thing two, the bnc connectors and switches on the case make contact to the coating so i dont need an extra ground wire to the case.
Not sure how to test how good it is shielding.
>>
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anybody know how the fuck to add multiple references to an input in quartus? i'm sure it's extremely obvious but i've missed it.
>>
Could i use a ZVS driver (used for induction heating) for driving piezo elements like pic related?
>>
>>1314358
If you want to drive the piezo at it's resonant frequency yes.
>>
>>1314091
If you have a function generator and an oscilloscope, you don't need one. Put the unknown inductor in series with a known resistance across the function generator's output (like the function generator's own 50 ohm output impedance) and measure the voltage across it.
Knowing the inductor's impedance at a known frequency and you know the value. The impedance divided by two pi the frequency gives the inductor's value.
>>
>>1314043
I like the way that this iron looks and the small package, but how does it deal with soldering to things that would act as heatsinks? I think I am ready to move on from my current iron, which is just one of those that you plug into the wall to something with a wider variety of tips and temp control, but since I occasionally work on guitars, I would like something that can solder onto the back of a potentiometer or a ground point on a bridge if needed.

My choices are currently between this and a Hakko t12 tip compatible iron off of Aliexpress, but so far I am leaning towards the t12 compatible because of the tip availability and selection.
>>
>>1314354
factor your design better
make those inputs separate and tie them together at the next higher level of your hierarchy so that when user testing determines that 32Hz is the wrong speed it can be easily changed... and so that you can reuse easily
>debounce
that's not a debouncer, just a synchronizer. AND the D outputs together if you want a debouncer.
>asynchronous clocks
compute D instead of the clocks, or use a counter macro and enable only when a key is down and the counter isn't at max
>not using an HDL
use an HDL

>>1314473
hakko clone. the TS100 may become literally too hot to handle if soldering up a whole guitar including proper shielding
>>
>>1314486
>that's not a debouncer
seems like it would work fine though. note the input tied to the reset pin. it just requires the input to be continuously high for at least 32ms to cut out the bounce period altogether.
>asynchronous clocks
maybe i don't understand. i'm using a cd4060 as a clock source because i need a crystal driver anyway and that one saves me some of flops. is that a bad idea?
>not using an HDL
any good web based sources for learning it? all my knowledge is in the C family.
>>
>>1314493
>it would work fine
fair enough, as long as your switches aren't super bouncy.
>cd4060
is a ripple counter. a ripple counter's outputs skew as carries ripple toward the MSB. it can sometimes work, and at low speeds like this it might not be a problem. generally, if your synthesizer knows all about the timing it can do some nice things for you like identifying critical paths and telling you the max clock speed of your design. if you're targeting an FPGA, 100% area utilization never happens anyway, though the optimizer can try pretty hard.
>using an HDL
the Verilog tuts here look bretty gud, albeit with a couple of obvious typos and a touch dated http://asic-world .com/
>>
>>1314135
>Thanks, I will try both. Seemed like a good idea to simulate the vhdl and be able to add discrete components visually too, but I guess it wasn't meant to be.

It may be hard with opensource tools but it will work with tools from Xilinx, Altera, Actel/Microsemi like a charm.
>>
>>1314472
alternatively, put it in parallel with a known capacitor, sweep frequency to find the resonant point.
>>
What's the difference between 5v and 12v led strips? Do they just wire them in series of three?
>>
>>1314716
>What's the difference between 5v and 12v led strips?

about 7 volts.
>>
Just pulled the trigger on the Siglent SDS1104X-E. Did I make a good decision? It was a bit of a toss up between it and the Rigol DS1054Z but I felt the Siglent's hardware edged it out somewhat. Also thought about getting the 1202X-E instead but I've read that the 1GSa/s sample rate isn't really adequate for the 200MHz bandwidth so I figured it wasn't worth it. Didn't get the arb gen option.

Already have an HP 54645D, Tektronix 2430A, and Tektronix 2225 as well for scopes but this will be my first modern one as well as first four channel.
>>
>>1314716
basically, yes
>>
>>1314352
>Not sure how to test how good it is shielding.
To do it right you need a broadband antenna and an RF spectrum analyzer.
If you are serious about shielding, get the book Electromagnetic Compatibility Engineering by Henry Ott
There are chapters on how EMC testing is done, and how to do the tests yourself, and what shieldings are suitable to use for different frequencies.
>>
>>1314942
>Ott
that's a very thicc and expensive book. thank heaven for vietnamese PDF fishing boards
>>
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What's the difference between a Master-Slave JK flip-flop (such as CD4027) and 'ordinary' JK flip-flop such as CD74HC109?

I'm planning to build a little circuit mostly based on JK and D flip flops. Which type of JK should I use?
>>
>>1315424
They do fundamentally the same thing but different tech maybe cmos vs ttl or some shit i don't remember sorry but it's too do with power and fan out and speed probably. Fan out is how many inputs one output can drive.
>>
>>1315424
A regular FF outputs the results immediatly, which can cause problems when chaining them, like in a shift register with all FF's using the same clock edge due to different propagation times. The output of one may change too fast which would invalidate the input to the next one, possibly causing unpredictable results.

A Master-Slave FF does it in two stages to prevent the problem. The input is used on one clock edge(master FF) and the output is set on the other clock edge(Slave FF).
>>
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got an old WLAN router that i wanted to use but it is not working. i checked the power supply with my oscilloscope and got pic related when i applied different loads. it is rated for Output of 5V/1.2A

the output voltage sure doesn't look right and now i am curious what might be the cause of this. does anyone have an idea?
>>
>>1315481
I'm gonna guess output caps open
>>
>>1315489
yes i figured that statistically this might be the most probable cause.

but then again, wouldn't the open load voltage be oscillating more? it's almost constant
>>
>>1315493

caps, just like people, dont go directly from being healthy to being dead. their capacity reduces with age, esp when worked hard in a switching power supply.
>>
>>1313592
You need something USB capable and read the USB standard on HID devices, most keyboards (all?) should be HID class.
>>
>>1315650
Thanks for the reply, I ordered a mini usb host, along with arduino micro pro, and have an idea now. Thanks!
>>
>>1315424
HC109 is J, /K, /S, /R
4027 is J, K, S, R
both clock at CP L-H transition
RTFDs
>>
>>1315493
on second thought it could be the flyback diode blown or the switch transistor degraded. without seeing the design it's kinda hard to tell. now you've committed to breaking it open and troubleshooting it and posting your results here. you know that, right?
>>
>>1315793
yes i want to do that because i would learn alot. but dont have proper tools at home rn to break it open without destroying it. there are no screws or anything. will try to do it as soon as possible
>>
>>1315796
I wouldn't worry much about destroying a device that's broken in the first place. it's not like you're going to fix it any other way. anyway, no problem, I will be watching with interest to figure out how that waveform got there
>>
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>>1315796
Carefully cut around some equator, then crack it open. You can glue it together again.
>>
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>>1315798
>>1315822
rrrreeee why is this thing so fucking solid, really struggled to open it up and cut myself. whatever it's open now

output caps (green ones on the right) definitely look bloated and not healthy. you can kind of guess from the pictures.

the output diode (big one on the right) measurement shows low impedance when it should, but around 2kOhm when it should be high. so either the diode or the caps are the problem, right?

the IC is a VIPER12A
>>
>>1315842
>around 2kOhm when it should be high
Rest of the circuit. You need to unsolder one end of the diode to measure.
>>
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>>1315847
yes you are right. very naive of me. when i looked closer i noticed this little 2k ohm resistor. i assume it is a minimum load, yes?

there is no optocoupler on the secondary side. i suppose the feedback works with an auxiliary winding on the primary side

will try to desolder diode soon
>>
>>1315847
>>1315858
the diode seems to be fine. will make myself a schematic to fully understand the circuit.

i have two questions tho:

- there are 3 parts covered in shrink tubing (top left of first pic). whats the most likely reason for that? isolation? i kinda want to remove it to see what parts are hiding under it

- also why do SMPS transformers almost always have that plastic wrapping? is it simply for isolation purpose?
>>
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>>1309922
So I want to build a BLDC motor from scratch for shits and giggles. If it turns out to work well, I might find an application for it.
I took an electrical mechanical course back in my undergraduate years and we learned all the theory behind electric motors, so I have a general understanding of how to build one and how they work. However I don't have any resources to actually design one from scratch based on various parameters (desired torque/rpm, input voltage, watts, max height/diameter, etc).
I have access to 3d modeling software and circuit design software and can get parts CNC machined by my uncle. It's just a matter of designing all the parts now.
Does anyone have resources that they can point me in the direction of? Heck if they have resources to build any sort of electric motor (brushed dc, induction, synchronous ac, etc) that would be useful. It may even turn out that based on whatever parameters I decide on, that I may need to build a different type of electric motor.
>>
>>1315891

Not too many people design motors so there might not be too many guides, however all of the information is available in raw form. You already know the physics of electromagnetism from that course where you learned "all" the theory.

So to apply that knowledge, decide whether you are going to purchase stator lams from a catalog or design your own. In either case the material will have magnetic characteristics that the supplier can give you.

Same goes for the rare-earth magnets you will buy. Whether you design custom shaped ones or buy off-the-shelf, the magnet supplier can provide the data sheets.

Then it's just a matter of designing the windings and so forth. The theory that you learned includes the relationship between magnetic flux, current in conductors, and induced voltages. You already know from your coursework that you want to have the right level of magnetic flux in your rotor iron and stator lams so that they are not saturated, so that dictates the geometry of those things with respect to the magnets. And as for the winding, your pic shows a terrible design in my opinion; the stator slots should be nearly full of copper; that motor could be considerably smaller and perform the same, or could be the same size and perform better.

Once you put all this together, make a video. There are some cool youtube videos where guys like you made pretty nice motors, and I'd like to see yours.
>>
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>>1315874
>parts are hiding under it
one resistor and two of the four mains diodes i'd say
>will make myself a schematic
very good
>>
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>>1315443
I just tried it with a CD4027. When I first apply a high signal to the J input pin (K = low level), and after that apply high level to the clk input pin, the outputs Q and !Q are changed immediately.
From your explanation I understood that the part would read the J/K inputs on positive-going clock transition and then output the result on negative-going clock transition. Even its datasheet shows the outputs changing only on positive-going clock transitions. I just don't get what's going on.
>>
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What's the name for op amps whose output can hit one of the power supplies like the lm358/lm324? I don't need rail-to-rail, it just needs to hit ground and not have such awful slew rate/HF gain as an lm358.
>>
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>>1315938
>one resistor and two of the four mains diodes
yes almost. two of the diodes and actually a fuse.

pic related is the schematic, pretty sure its correct. the only part i'm not sure about are the 4 numbered diodes:

so diode 1 is for rectifying, diode 2 i assume is a zener diode. it looks different than the others and a normal diode wouldnt make sense. so if a certain voltage on the auxiliary winding capacitor is reached, current starts flowing throw zener diode 2 into feedback pin and eventually makes the switch turn off. by regulating the voltage behind diode 1 the actual output voltage is regulated aswell. diode 4 i guess is another zener diode protecting the IC against overvoltage. but diode 3? i dont know

now the question is what parts i should switch out to see if it helps. i guess i should start with the output caps
>>
>>1316048
LM324 and LM358 are sold as "single supply" opamps. That's an old name though and nowadays they're often handled as a special case of RRIO amps. For example, TI sees them as "input to V-" amplifiers and doesn't mention their output in the parametric search.
>>
>>1316048
I can't find anything about this in the datasheet, but I've used TL082s with a single supply and was able to hit ground, or at least close enough.
>>
I've got a few questions as a mechanical engineering undergrad with poor understanding of basic electronic components:
If I give a solenoid more voltage than it is rated for (5V provided when it is rated for 4.5V), will it operate fine, burn out, or not operate at all?
If I want to use an Arduino to control said solenoid, I will need to use a transistor to bridge the power from the 5V regulator to the solenoid, switched by the Arduino output signal, correct?
>>
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>>1316051
Looks a lot like this
>>
>>1316095
>will it operate fine, burn out, or not operate at all?
it should work fine, but might burn out aswell. depends how much current the windings of the solenoid can tolerate

>I will need to use a transistor to bridge the power
the arduino output pin will most likely not be able to supply enough current. so yes you would have to use a transistor in combination with the output signal
>>
>>1316120
Thanks.
>>
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Any tips or tricks for designing circuits with Manhattan style construction? I've never done it before but I'm looking to try it out.

What kinds of tools would I need for this? I think I probably want a nibbler to cut out lands, make separate analog and digital ground planes, and cut isolation slots. I also probably need something to cut boards down to size since I don't have any tools capable of doing it atm, not even a simple hand saw. Will a dremel work?

The little lands I cut out are actually isolated from the copper plane below right? I mean, I'm sure they're capactively coupled but it's not a direct short circuit right? Do I need to put some insulating material between them?

Also, how do I solder directly to the ground plane? I have an FX-888D. I normally do my soldering at 750 degrees freedom but should I turn it up to attach components right to the copper?

Also, how do I solder ICs this way?
>>
>>1316245
>I also probably need something to cut boards down to size since I don't have any tools capable of doing it atm, not even a simple hand saw. Will a dremel work?
Dremel with cut off wheel would work.

>The little lands I cut out are actually isolated from the copper plane below right?
What do you think? Of course they are isolated. They would be useless for this purpose otherwise.

>Also, how do I solder directly to the ground plane?
Same as soldering anything else, but might take longer to get the area heated up. A drop of flux on the board helps heat transfer from the tip.
>>
>>1315926
I was afraid that I'd have to end up pulling up my old notes from that class. Shame, thought there might be some guides out there that I could follow along and plug in any additional information with the raw theory (basically what I've been doing with any circuitry I try build).
>>
>>1315891
Good luck making your own laminations. But in terms of design, all you should be worried about is maximising the efficiency of magnetic flux in all points of rotation.
>>
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>>1316245
>750 degrees freedom
350 degrees Celsius are enough.
>>
>>1316245
what exactly is the point of doing this instead of just using a perfboard and wires
>>
>>1316363
Lower parasitic effects, important for RF designs.
>>
>>1316245
you could score the non-copper side of the laminate several times with a hobby knife and straightedge and break it off.
>>
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>>1315481
>>1315842
>>1316051
switched out the 680µF cap for a new 1000µF cap and now the waveform looks like pic related. router is working again. kind of boring but whatever

guess the 330µF cap might be ded aswell or soon atleast, but i assume the supply would still work. didnt want to spend another part kek
>>
>>1316252

can you or someone explain what is going on here? is there a thru hole that connects to something on the other side?
>>
>>1316409
hurrah

>>1316410
those are glued-on pads punched from copper clad laminate. components are soldered to the rounds to pass signals, or to the copper ground plane below.
>>
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anyone know what these connectors are called?

used in rack power supplies of various formats, but never caught the name.
>>
>>1316416

the individual ones are spade terminals. I don't know if the array has a name.
>>
>>1316430
i found it.
din 41612 h15
>>
>>1316410
they go nowhere because its just a demonstration.
>>
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>>1316245
Manhattan stomptronics.
https://www.parasitstudio.se/building-blog/manhattan-style-pedalbuilding
>>
>>1316441
goddamnit the fuzz pedal guys can turn anything into a meme
>>
>>1316410
>is there a thru hole that connects to something on the other side?
NO
>>
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Just ordered this new soldering station, wxmp wx1011, what do you guys think?
>>
>>1316482
nice, i have an old wd1, auction buy at $20 lol
>>
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>>1316410
>>
>>1316482
i like those

>tfw have extremely shitty one because cant afford better
>>
>>1315874
>there are 3 parts covered in shrink tubing (top left of first pic). whats the most likely reason for that?

the heatshrink will contain the shrapnel in case the part asplodes.
>>
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I'm trying to beef up one of these electric peltier based coolers in the picture. If I just swap out the low wattage cooler included for a higher one on the heatsink assembly will things be relatively alright? This is assuming my power source and all the other components can withstand the increased power draw. Has anyone done anything similar?
>>
>>1310550
There are beefier esp modules than the esp001. They have more memory, and you might just be able to use them as the actual mcu itself.
>>
>>1316577
1. The TEC is likely bonded to the heatsink somehow
The TEC likely takes the same voltage but more current. You'll need another cooling apparatus for the power supply section which is almost certainly not designed with any unused power-handling capacity.
>>
>>1316577
>>1316587
At least it was all epoxied together when I last stripped one of those... you might do better by improving the cooling of the hot side, since the whole thing should be expected to produce a temperature difference hot-cold. Is this to make it colder, or to allow it to actually move units/heat faster?
>>
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>>1316587
>>1316594
The goal is to keep the contents below freezing temperatures for long periods of time. It'll be sitting in a room at about 23C. It seems like it uses the same generic modules you see on every site, but I think your idea about just lowering the temperature of the hot side sounds better. I suppose it's a matter of replacing the hot side fan or heatsink, or maybe both. Maybe I'll just throw in a larger or more powerful fan and see how it performs. There are also cooler models that seem like they have dual peltier modules, but installing a new one probably isn't worth the trouble.
>>
>>1312201
>ill report back once i've riced it
did he die?
>>
>>1316617
>keep the contents below freezing
Good luck. Peltier needs 4 times the energy of a small compressor cooler.
>>
>>1316580
I actually bought esp12.
>>
>>1316654
Yeah, I understand that they aren't very efficient or all that effective. Power usage isnt an issue but space and price are. It's not intended to do any serious freezing, just a few small things. I'll post if I end up getting it working.
>>
>>1316654
where does one get a small compressor cooler
>>
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Guys help this retard out, I am wanting to hook my esp8266 to arduino board (it will be pro micro in the future, for now its uno/leonardo), and how do I hook up 5v to 3.3v? I want to mainly do it on resistor series, but I am just wanting to make it small as possible.

I am so fucking retarded, help.
>>
>>1316789
Build a voltage divider circuit, or get an ic for level shifting. You can also just use an esp12 module by itself instead of using any arduino at all.
>>
>>1316354
>100°C sag
Wow how has nobody improved on that
>>
Does anyone else like the smell of phenolic resin boards?
>>
>>1316793
It seems that mainly for 5v input, while I am wanting to use 5v output on the board, would ams1117 3.3v do the job?
>>
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>>1316834
More power, less sag.
>>
>>1316862
>100W isn't enough to stop the total temperature from decreasing when soldering continuously
I hope this isn't the case.
>>
>>1316866
>>>1316862
>>100W isn't enough to stop the total temperature from decreasing when soldering continuously
>I hope this isn't the case.


I have a 60w cheapo iron, and for Christmas I made some knick knacks for the family. It was a frosted glass jar with 10 led lighting up around each jar.I used a 555, a cd4017, capacitors, resistors, plus a 4AA battery pack... 15 times. I made them all in one go in a cold garage, and everything was fine. I never had any temperature problems. The 60w iron kept chugging on and on.
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So I'm trying to get this bt speaker to dance by bouncing up and down a little, while at the same time leaning from side to side. Any ideas? I'm totally stumped. I don't mess around with motors much. I do have an extensive collection of rescued motors from VCRs and tape decks.
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>>1316879
You'll need motors with a gearbox to make it move smoothly, and getting something for that form factor will be a challenge.
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>>1316853
Yeah
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Hello all

I am by no means a scientist and have been press-ganged into building an ASTM compliant salt fog cabinet using off the shelf parts for testing a coating. We are basing our design on this other man's work https://www.finishing.com/97/21.shtml

but I've hit a snag. pic related is his shematic for the electrical wiring.

fucking what??? where is the return????

I haven't taken anything with circuits since AP physics in highschool like 10 years ago. I know it's AC and so theoretically you could go without an actual return via the ground (though, fuck it, you could also theoretically do this with DC for finite amount of time technically speaking).

Is there something I'm not seeing? how would the wiring of this actually look? and is there a simpler way to do it?
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>>1316926
so far we have all the electrical parts except the solenoid and the air compressor -- the timer, the thermostat, the heating element for the pressure cooker, the busboard (8 slot), the breaker, and several relays (rated for 10 amps at 240 volts rather than 20 at 110 and should be sufficient unless i am massive fucking retard). this is not merely daunting to me on its own, but adding salt water into the mix also makes it an easier time to get shocked.

pic related is a view of some of the guts of the original designer's creating (all available on the link in first post)
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>>1316926
>where is the return?
Ground symbol means N (neutral).
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>>1316928
explain this to a retard how that works in the case of AC circuit as all AC circuits (from highschool) have had a return while a neutral ground functions as a safety feature. sadly my googlefu is drawing up blanks on this
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>>1316931
>) have had a return while a neutral ground

Neutral is the return (in america usually white, with hot being black or red).

Ground is a safety and should not carry current ordinarily (green or bare wire in america).

the ground symbols in that drawing are to be connected to neutral, as >>1316928
said.
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will i need to do anything when soldering solid core copper which is exposed to atmosphere to stranded wire? im worried about oxidation of the copper. is it ok to solder these 2 types of wire like normal soldering???
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>>1316928
It's drawn kinda wrong, by the ground symbol there they mean neutral.




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