/diy/ - Do It Yourself

I can't believe I'm having such a hard time finding info on something so basic, but how do I wire a female 3.5mm jack?
I'm trying to add audio out to a shitty synthesizer of mine. The little speaker has two leads, power and ground, heading to the speaker but the jack has 3 prongs. I assume this is because the synthesizer is monophonic, but the jack is stereophonic. What do I solder to what?

>>1295432
also, if I want to switch between either the 3.5mm out or the speaker, would I be looking at a DPDT switch to switch between the two?

>>1295432
Tip and ring would go to the "power" lead for your speaker, and sleeve to ground.... But...... You don't want to do that, unless you turn the speaker signal into a line level signal. Try to find where the audio signal is before it hits the amplifier and take it from there. If you run the amp output into a line level input it will most likely blow the input in your device.

>>1295432
For a stereo socket being used with a stereo aux cable, you'll want to wire up both the end contact (the tip) and the middle contact (the ring) to the same signal, while the base contact (the sleeve) to ground. But if you plan on using a mono aux cable then leave the centre contact unconnected because a mono cable can short the ring and sleeve together.

If you're going to plug this into your computer's microphone socket, check the DC voltage from each contact to each other contact with a stereo aux cable to ensure they're all 0V. Electret microphones (what headsets use) require a DC voltage input which they output a low amplitude AC wave over the top of, which is why a TRRS audio output on a netbook will have 2.4V or so between its sleeve contact to second ring contact. If you've got a DC voltage with a TRRS or TRS socket on your computer you'll need to put a capacitor in series with this and perhaps a trimpot to decrease the signal's amplitude.

>>1295457
Since it's mono, an SPDT switch will work if you don't mind leaving the ground lead connected to both, but since that can cause interference issues you should probably go for a DPDT anyways.

>>1295474
SHit, also this.

>>1295474
Also, if you just use the signal before it goes into the amplifier, you can just use a regular rocker switch with 2 contacts to interrupt the powered signal going to the synth speaker to turn it off and on as you wish.

>>1295474
>>1295475
So, I should essentially bridge/attach another lead from the synth + to the the opposite contact of the yellow lead then?

also, it's a battery-powered handheld electric piano (yamaha pss-30), does it even have an amp capable of wrecking my audio interface?

>claims to be into electronics as a hobby
>doesn't even know ohm's law
>just buys arduinos
Some people are just living memes

>>1295484
I found the amp. It's a jrc3860.

>>1295489
That's why I'm trying to build my own effects boxes and circuitbend stuff.
Using an arduino to blink an LED bores me to fucking tears, I want to make practical stuff that I can actually use.

It's a shame I can't find any info on beginner effects pedals/boxes either. I'm a long way away from designing my own anyway.

>>1295484
I'm not sure of your pinout, but yes, you would bridge the left and right so that your mono signal goes to both left and right on your other device. As for the amp, yes it could clip the input and burn the channel out on your interface.

>>1295498
I found the last lead before the input of the amp, it's the output of a capacitor on the underside of the board.

Any suggestions on how to make it a bit more rugged so it doesn't break the second I screw the board back on? It's a rather small contact
I'll probably have to get some much smaller gauge wire or something tomorrow

>>1295501
Solder it in a way that it will not bend, and maybe use a bit of hot glue to hold it in place.

>>1295504
>hot glue
Or silicone, or even better silastic if you happen to have it.

>>1295513
I used silicone once. The little box I used for that project still stinks like chimneys, is something

>>1295528
Not chimneys... My bad. Vinegar

How is the overcurrent protection part of this circuit supposed to work? I'm so confused.

>>1295695
if the current is too much one of the transistors releases excess smoke through a blowoff valve

>>1295707
Are you saying this circuit doesn't work? How is this done properly then?

>>1295695
R2 creates a voltage if too much current is applied, the voltage in R2 causes current to flow into Q2's base, this activates Q2 and robs Q1 of some of its base current, reducing the current flowing through Q1, controlling the output voltage in case of overcurrent.
Q3 seems to be used to regulate the voltage by controlling the current drained to ground, which would otherwise go through Q1's base. The zener is probably used to have a minimum voltage.

>>1295695
Current through R2 produces Vbe of Q2 and if I*R2 reaches about 0.7V, Q2 starts to conduct and bypasses base drive current of Q1. So Imax=0.7V/0.09Ω=7.8A which seems too much.

There was an error in the diagram.

>>1295713
>>1295714
So if its working correctly the output current shouldn't go over 8A?

But when i simulate its almost like it's doing nothing. I get the 0.7v drop and the current into the base of Q1 goes down slightly but the output current keeps rising.

Call me a retard but i have a ceramic fuse that i need to test. It reads 0 ohms on every setting in my multimeter. Is it burnt?
>inb4 google

toner transfer experiment

I probably shouldn't have been too lazy to prepare the pcb properly

>>1295732
looks fine, you just left it in the etchant a little too long

>>1295750
Nah, that's the toner coverage.
If you look closely you can see where I filled out the ground plane a bit with magic marker.

>>1295719
>output current keeps rising
What makes you think it would not?
What prevents a meltdown of Q2?

>>1295763
I meant the current kept rising at a similar rate. I think I understand it better now.

>>1295769
This circuit is really a borderline construct. For such high currents there are much better ways to realize a linear regulator and a current limiter that is adjustable and does not feed the drive current into the output.

Why borderline? Imagine you remove R1 (no load, totally normal condition) and set R5 to zero. Then you have an output voltage of about 12V. A good simulator game would now launch an animation showing you how D2A is going up in flames while immolating the unused D2B with it.

A spell checker doesn't teach you grammar.

>have a whole bunch of components coming in the mail
>just finished NEETS module 1
I am both excited and feel like a brainlet

Anyone knows some good ARM tutorials/books? I have a Tiva launchpad and a stm32f4 discovery board and am currently using keil for programming.
I would also like to program in linux if it isn't too much of a hassle.

this is only semi-/ohm/ related, but why does the power supply to the drum machine I just got in the mail have a male 3.5mm jack instead of a standard plug

>>1295851
Because its the wrong one.

>>1295853
awesome, thanks ebay.

>>1295854
If the adaptor has the right voltage and is AC, just snip it off and replace it with a 5.5/2.1 plug.

>>1295858
That's why I'm so confused. The adapter's correct with everything but the plug
I'm going through every spare power supply I have and I can't find a single plug that fits though, even a 5.5 plug
It doesn't look proprietary, but I can't for the life of me find one that fits

>>1295861
Oh shit. Some power supplies come with a collection of plugs. Can you measure the inner diameter of the jack?

>>1295868
The internal diameter is 5.5mm, I'm at a loss as to why none will fit

Are chinese ebay components any decent? I am checking out
https://www.ebay.ca/itm/261838713039
and am wondering if their claims about quality are true. Would it be the same as a BPW34 from digikey, or would it differ?

I built this LED Christmas tree from a Velleman kit when I was little. I found the kit's manual from their web site and it claims 8 mA current consumption from a 9 V battery.

How much would it improve the battery life of the tree if this simple circuit was re-implemented with a low-current CMOS logic IC? I guess CD4000 series IC would be optimal in this regard: very low (<10 µA) supply current and operating voltage from 3 V up to 15 V.

Another way to save a lot of battery power would be to add an LDR light sensor and a low-power comparator IC such as MAX921. It would automatically shut down the blinking light show during the day.

man, why are 3.5mm jacks so expensive
why are all components so expensive

>>1295878
seriously, all these beginner books want so many disparate components to build simple stuff, is there a "common electronic components bulk pack" thing that anyone sells

Asked this last thread but it ended up dying before I could check back. Is there a way to repair a broken meter? I keep having to buy replacements when the mA setting fails.

>>1295884
Are you blowing the fuse? There are self-resetting fuses you can buy, not quite sure what they're called though.

>>1295877
CMOS is not worth the effort, base current is much smaller than 8mA. Switching off during daylight is more effective.

>>1295877
First of all figure out how much current the leds are using (hint: 99%) and how much the oscillator is using (hint: None)
Sketch it up in spice and stimulate it if you don't mind tearing your hair out lol.
What IC are you going to use? What is its function?
Ldr could work but there are more simple ways than dedicated IC. If you are trying to learn the basics then stick to the basics, avoid manufacturer specific chips if possible!

>>1295885
I'm not sure, there's no fasteners for me to get at to check the fuses.

>>1295890
>Sketch it up in spice and stimulate it
I wouldn't, Spice doesn't like relaxation oscillators very much.

>>1295894
Wait wait wait, you just buy replacement Fluke multimeters??? Are you fuggn rich or something? If you take the rubber case off them there should be screws underneath.

>>1295901
>doesn't like
I alluded to that but I thought in all the time since I did it at school perhaps it might have improved!
In any case you can see even before accounting for the led voltage drop the current through the led vs base switch is 100:1

>>1295877
How many batteries can you buy for 1 LDR and 1 MAX921 delivered?

>>1295428
How to disassemble laptop sealed power supply?

>>1295937
Functional or defective?

Alright, so bear with me, I don't know much about electronics.

My old amplifier started acting up on me. It's a Pioneer SX-3800 from 1978. It turns on, but the LCD doesn't turn on. I used to hear the initial 'click' of the main power switch, then a second, softer 'click' as something inside turned on. I think whatever makes the second 'click' is what's broken, because I'm not hearing the sound anymore.

I'm guessing that whatever component is running the LCD is what also runs the input selection and actual audio output.

What should I do to dig deeper and diagnose/solve this problem?

Thought I'd share a project I've been working on. An electronic dart scoreboard for cricket. Built entirely because I don't want to do math in my head, especially when drinking.

Code is done for it. Has undo/redo for up to 25 moves, calculates score automatically, and makes pretty lights.

I got gypped on the alphanumeric displays. They sent 4 of the wrong color and won't respond to emails. So now I gotta find a replacement, none of which have the same pinout as what I designed. So those boards need to be redesigned.

Last step will be to machine the face plate, then use a stencil to paint the numbers on.

>>1295937
I'd advise against it unless you know what you're doing

>>1295938
Functional, but with bad cable.
>>1295946
>I'd advise against it unless you know what you're doing
I want to change the worn out cable.

But this thing doesn't want to come apart.

>>1295940
Easiest thing first. Open it up and juggle things to make sure connections are good, and then check for the shit-stains. If something looks like something has spilled, there's a bad capacitor somewhere(that leaked stuff is conductive and maaay have friend things, but thats a maybe. Alcohol will clean it up.), if capacitors look bulged, they're dead or dieing, and if anything looks burnt or scorched, it went pop, let the smoke out, it ded, replace it. And if it has fuses, check for continuity/make sure the resistance isn't absurdly high with a multimeter. Any friend that does electronics has one, you can buy ones that aren't shit for $30 online, or even get the free one at Harbor Freight, it's shit, but it'll serve your purposes.

That's the easy stuff. After that it gets into knowing what's going on.

>>1295946
if they knew what they were doing they wouldn't have to ask

>>1295956
I know how it works, that it is switch-mode PSU, that have natsy HV caps that can shock you to hell and beyond, I just do not know how to disassemble this shit without damaging the case.

>>1295956
>>1295949
what I meant was, if you don't know the power supply capacitors can give you a bad shock, you should probably leave it alone

>>1295953
Granted I can't see every side of every board inside but it all looks good on the surface. No bulging or leaking caps, nothing looks burnt or scorched. It was dusty as fuck though.

Only thing that looks weird is this, I have no idea what it is, but the back says:

>BANDO
>BE91h-0003A
>ATT-667
>O-BE11-ZLK

Google says it might be a transformer? Either way it looks kind of nasty.

I'm not really sure how to identify a fuse. I do have a multimeter though, one of those cheapos from Harbor Freight as it turns out. Other than that, I'm a bit dumbfounded by all the different boards and parts.

>>1295975
forgot pic

>>1295960
This is your tool of choice. Carefully cut around, then crack it open with a flat screwdriver. When all is done glue it together again.

>>1295982
Hmm... Okay.

Maybe it worth trying to pour some solvent to seam, maybe it will help...

circuit bending brainlet here again
so I tried wiring up the audio jack to the preamp line output, bridging the two contacts, and then wiring up ground. Pic related.

However, instead of outputting through the jack, it will only play out the speaker when there is an aux cable in the jack

>>1296003
>preamp
as in before the amp, not an actual preamp. Shit.

>>1295979
Looks like a transformer, but they always look pretty crusty. If you can get a nice picture of each board that would be good, and of both sides if there are components on both sides. Fuses are typically either a cylinder of glass or of white ceramic with a metal end cap on either side, from 5mm to 15mm wide and 15mm to 40 long. Sometimes the ceramic ones have lettering on the side.

>>1296008
Alright, thanks for the info.

I will do my best to take pics of the boards, I"m still hesitant to disturb parts but I'll do further if needed.

>>1296003
that's a mono jack with a switch, my dude. if you want to use the switch, you need to put it in the middle of the signal path like Pic related. also, if you're feeding a stereo line-in, you'll need a mono-to-stereo cable or adapter to split the output to two channels.

>>1295877
meh, this is why microcontrollers have eaten the physical world. one photodiode to an analog input and you're rolling.
that said, you could just drop a MOSFET into the ground power lead with a resistance, probably > 30kohm, chosen to allow an LDR to pull the gate low enough to stop current flow when it's bright out there but not when it's not. adding hysteresis, if desired, is left as an exercise for the reader.

>>1295876
>and am wondering if their claims about quality are true. Would it be the same as a BPW34 from digikey, or would it differ?

You can never be 100% sure with chinese components if you are getting the real ones.

If you are designing something non-critical of is it's just your hobby go ahead and try it.

I personally do not shop on aliexpress and ebay and yet I got a like a dozen or two of fake components over the years.

>>1296043
man I don't know what the fuck I'm doing apparently
The synthesizer is mono, and the switch doesn't matter. I just wanna add an audio out so I can hook it up to my desktop's audio interface

>>1295989
Nope, terrible idea. At best, it does fuck all, at worst, it gets all gooey and stringy as you pull it apart, getting everywhere in the process, or it melts enough that it drips inside.

>>1296016
>I"m still hesitant to disturb parts
It's already broken, I wouldn't worry. Worst-case, you're exactly where you started.

>>1295901
I didn't realize the yellow was a case, I thought it was some kinda overmolding. Looking back, I don't know how the fuck I thought the stands worked or how I'd replace the batteries. But thanks! I have some fuses on order now.

>>1295940
>Pioneer SX-3800
Damn that things a smokin'

Hope Mr.T would tell you how to fix it

>>1296059
Better be legit Fluke fuses my dude.

Will the beginner books in the OP help me build this analog bass drum circuit?

I am starting from zero

>>1296136
Build it maybe, but not really understand it.

Trying to simulate monet switch in ltspice. How do I control the voltage at which the gate olen? Atm it opens even from the slightest voltage

>>1295884
Gee Tommy, why does you mom let you have FOUR Flukes?

>>1296136
Probably, so long as the books explain active (as opposed to passive L/C) filtering, op amp theory and uses, transistor theory and uses, along with ohm's + kirchoff's laws. But as someone who more or less knows all that but has no experience in dealing with real synths or pedals, it would take me a few/dozen hours to really get my head around how that thing works. If you just want to make it, then as long as you get the basics of PCB construction then you should be fine.

>>1296118
Seven bucks on Amazon, might as well.

>>1296105
>Hope Mr.T
You are no better than that faggot. Fuck off.

>>1296136
>I am starting from zero
Better get a kit.
https://www.google.com/search?q=analog+bass+drum+circuit

>>1296145
Neither are you, mob-kun.

>>1296139
>monet switch
explain

>>1296152
Goddomanit. Mosfet*. European autocorrect

>>1296159
Ok, have a diagram? Type of MOSFET?

>>1296163
At my cell atm sry. Its the default ltspice n mosfet. Will post later.

>>1296105
muh dick

I posted a few days ago about a walkman not outputting audio correctly, but I didn't find a solution to that.
The more pressing issue wich I've just discovered is audio being played back at a significantly lower pitch than on my cassette deck.

https://vocaroo.com/i/s1VHM6eeq2an

Are the belts slipping? Where could I get some new belts?

>>1296138
That's fine, I'm trying to make instruments for myself, not trying to study EE

>>1296141
>>1296150
Thanks!

>>1296188
>belts slipping?
Not likely, would sound differently. Drive speed may be adjustable. Clean belt, head and everything that transports the tape with ethanol, look for good tape->head contact and adjust head azimuth. Don't expect too much from a worn out voice recorder.

>>1295428
how are these front panel mount infinite encoders that latch every couple degrees called?
I only find them without the latching feedback

>>1296259
Rotary encoders? Your typical arduino encoder might have a larger latch angle, you might want to check some parts browsers.

>>1295890
I'm thinking HEF4093B. This part has 4 * NAND gates with Schmitt trigger inputs. I could use NAND gates #1 and #2 as low frequency oscillators as shown on the datasheet.
Maybe NAND gate #3 could be used to sense the state of the LDR light sensor and to start/stop the oscillation on the gates #1 & #2?

>>1295931
I already have some LDR's and a MAX921 chip.

>>1296043
I thought to avoid using a microcontroller to minimize current consumption (and to keep it simple).

>>1296259

>>1296300
awesome chart, saved

alright this guy here again>>1295851
I managed to find the right plug, but the universal power adapter I got for it outputs 1200 mA and the sr-16 calls for 830, therefor I'm just going to solder the universal tip to the leads of the power adapter that came with the thing

my problem is I don't know what leads to solder to what. From what I know, AC current doesn't technically have polarity yet the adapter plug has a positive and negative pin. Does it matter which end I solder to what?

>>1296326
If it's AC then no, it doesn't matter.

>>1296295
What drives the 4 LED chains? 4093 output current is too small.

>>1295428
Last night I added a resistor to my LED and the current dropped from 350mA to 110mA, and that's the whole current, not just what's going to the LED, but the LED only got a little dimmer. The decrease in brightness is small enough that it's easy to ignore but the decrease in current has me confused.

Is this normal behavior for an LED circuit?

>>1296197
I cleaned everything to no avail, but I found this tiny potenciometer that made everything sound too fast or too slow (even when making milimetrical adjestments) and this was the closest I could get.

https://vocaroo.com/i/s1oyxSYLsdlf

So I ripped it out and soldered a variable potenciometer wich had 150 written on it and sorta found a sweet spot where everything sounded good, now I'm gonna glue it so it never turns again

(i have no idea what I'm doing, help)

>>1295428
1974 oldsmobile window switch. What wire does what?

Can i rig 4 momentary 3 way toggle switches instead?

>>1296170
Default sucks ass, you have to pick a specific model.

where do you guys get breakout boards for SMT components so I can mount them on perfboard?

>>1296441
sparkfun, polulu, I think adafruit too. Most hobbyist electronic retailers tend to have breakout boards for various SMD devices

>>1296441
they're generally called adapter plates or transfer boards on aliexpress. which is probably a better way to get a few dozen of them.

>>1296295
>minimize current consumption
>keep it simple
go with the MAX921+LDR solution driving a MOSFET switch, then?

>$1.95 part
>cheapest shipping is $4.05 to get it by next year
wew
alliexpress it is then >>1296468

>>1296471
>>1296468
>>1296445
these are what I'm looking for by the way, just blank smt boards that I can mount individual components to

>>1296474
turns out they're called smt to dip adapters. Now to find out where to buy them in bulk, or just make them myself

>>1296481
haha fuck you adafruit

>>1296484
you can shop harder m8

Could you use the output from a physiological signal say, heart rate, like the sensor in pic related gives as the input to a servo motor by using arduino?
Want to use my heart to power some shit, or at least reasonably pretend I do.

>>1296484
shop harder, fuck adafruit even harder
btw those almost fit two 3-pin SOT-23s on the wide pitch side, and the finer side can fit SC70-6 packages, with care.

>>1296496
yes

>>1296502
thanks senpai now we're ready to rock and roll

do any of you have experience with aliexpress soldering iron tips?

>>1296415
Do you have 'Auto' feature (when windows goes up or down all the way without holding a button). Or backlight of switch...

In cheap euro shitboxes (without 'auto') power windows are usually wired like this:

>>1296509
careful, those could be a touch too widely spaced for SOT23-5 packages to use without intentional solder bridging. I was referring to just soldering a single SOT23-3 on each side of the wide pitch area, which is not the intended use of those SOIC boards. you might instead want something like Pic related for something with opposing pins like a SOT23-{5,6}

>>1296516
UPD: Found photo of switch...
So, my guess it that one wire is common (brown usually is GND, but check it) and others are from relays.
You can replace it with 8 pushbuttons.
Also it may be the opposite, ACC is common and others have no voltage. (Most likely I guess)

Just turn on the key and measure voltages on wires.

>>1296518
Maybe a bit random, but what's people's general opinion about ordering parts from China? Is it decent quality or does most shit in devices come from the same factories in China anyway?

>>1296509
>>1296518
cutting it way close

>>1296509
>>1296522
Pic related: correct

>>1296521
kek, that is a topic of broad disagreement here on /ohm/. my take is that some things (resistors, caps, adapter boards) are harder to fake up, fuck up, or generally cheat with than others (diodes, transistors, ICs).
also, microcontrollers seem to be a bit more expensive by the ten or twenty through chinese surplus than through digi-key. go figure.

>>1296509
>>1296522
bonus: room for 0402 passives, if you're so ~~crazy~~ inclined.
/blog

>>1296521
I order pretty much all my shit from there because in the southern hemisphere the shipping from Digikey and such is pretty expensive. Of my ~30 orders from Ali I haven't had a bad order yet, but we'll see about that when my obscure P-channel MOSFETs arrive.

>tfw I want to solder a bunch of electrolytic caps onto perfboard in the shape of lettering like the Great Scott video opening and blow them all up in reverse polarity.

What appliances should I trawl gumtree (craigslist) for that have motors/etc worth salvaging from the 'free' section?

>>1296640
Old electronics, the new stuff is bound to be SMD which isn't worth salvaging. Audio equipment is also bound to have some nice large capacitors, so grab that old or new.

>>1296536
SOT23 is such a great package. I personally prefer these breakout boards because 0603 passives fit on the large pads of the pins fairly well IIRC (if the chip layout is miraculously kind enough to allow such convenience). Those pads are also crazy useful for attaching through hole components.

>>1296655
Forgot pic

>>1296658
nice, but damn, at $70 for a 50-pack. maybe designing one's own and sending for a panel or three from EasyCAD or OSH Park is a viable idea for simple, common topologies, like a generic op-amp circuit such as Pic related.

Which fume extractor should I get on a budget? Lets say 150 Euroshekels tops. Given that the only place where I can solder is my bedroom, I really dont wanna rely on open windows.

>>1296797
come on, this is /diy/
https://makezine.com/projects/mini-fume-extractor/
just do it with a larger fan

>>1296829
I know, but my lungs are on the line here so I would prefer something properly engineered...
And you are not gonna convince me that just blowing the fumes through any kind of carbon filter is enough.

How do you all pronounce "solder"
I'm being made fun of because I've always said it like "shoulder" without an h, but apparently this isn't right

>>1296829
>https://makezine.com/projects/mini-fume-extractor/
this piece of shit isn't an extractor, it's a dissipater.

>>1296833
your region get cold?

1) yes: connect a temporary flex-pipe or pvc to the kitchen or bathroom vents (if your parents bitch about it just tell them they wouldn't want their son
dying of lung cancer and they'll agree)

2) no: connect aforementioned contraption to your window and blow the fumes out via

total cost in euroshekels <10E, benefit via future cost of medicines unpredictable, but definitely worth it

>>1296855
you're a dissipator

>>1296859
i have become dissipater
destroyer of fumes

>>1296854
sahder. i'm from southern 56%.

>>1296854
sold-er
sold as in past tense of sell

>>1296854
sodder with Midwest country talk

>>1296879
This anywhere but the US.

>>1296854
sahder

Is it recommended to make my own ATMega328p programming board with ZIF socket and USB driver? It doesn't look like they'd be too hard to make, and the ones online look to be unusually expensive ($10), but perhaps I'm searching for the wrong thing.

>>1296935
>pcb: $5/5 unless made custom, assuming more that for protoboard
>uc: $2 on digi
>ch340g: $1 min on ebay, more if you want an ftdi or other
>ZIF socket: $0.5 on ebay
>passives, usb, regulator, pin headers: $2
>+shipping ($5?)
you can't make one for much under $10 but it's easy to make them yourself

>>1296854
Holder
Colder
Folder
Bolder

Solder.

>>1296935
>Is it recommended to make my own ATMega328p programming board with ZIF socket and USB driver?
I say a thousand times no. Use an in-circuit serial programmer.
If you're developing and have to unplug/program/plugin the chip more than 3 times you'll want to kill yourself. ISP development is so much faster and nicer it's stupid.
Take it from someone who made his own socketed programming board and junked it, moving on to ISP because socketed programming is such a frustrating fucking waste of time.
Yeah you might be "giving up" a few I/O pins, depends on your design, so use a bigger chip if that's a problem.

>>1296854
Sodder. Canada

>>1296950
> the cup hodders in my car are shit
> i'm going to put this file in my fodder
> i'm staying inside, its codder than a penguins ballsack out there
> he is just a little bodder than the average joe I guess

Is this really how retarded Canadians are?

>>1296957
Shut up you limey tooth sucking british bastard. North America > rest of the faggot planet

>>1296960
>limey tooth sucking british bastard
That's no way to speak to your father u cheeky cunt.

>>1296415
Is the harness relatively intact? If you have a battery in the car, turn the key and see which wires get +12v. Mark them. Then apply +12v to the cold ones one at a time to see what they do. Write that information down. Then you can make a decision on how to wire new switches.
t. Engineering student with '79 Pontiac

>>1296334
>>1296468
I played around with the CD4093 IC on Falstad simulator for fun and managed to get the circuit working. I used four PNP transistors for driving the LED strings.
LDR+resistor voltage divider connected to a Schmitt trigger gate switches all output transistors to "off" state when the LDR resistance rises enough in the dark. If it works in practice, this way there would be no need for additional comparator IC.

I might breadboard the circuit and do some comparisons between this and the original one.

>>1296936
>getting someone to make a PCB for you
Not me, friend.

>>1296947
>Use an in-circuit serial programmer
Ehh, won't that just bulk out my final PCB? I want to make a couple of the same thing so including prototyping components would be less than desirable, especially since I'm limiting myself to through-hole parts. And I'm doing the initial prototyping on an Arduino Nano. But I definitely see your point and aren't short of I/O pins; adding a programmer would certainly allow for easy modification later on.

Is the in-circut serial programmer you refer to just something like the CH340 USB-to-serial chip that comes on the obverse side of my knockoff Nano? I'd have to buy some anyway if I was making a USB programmable ZIF board, and they're 5 for $2.40.

>>1296854
it is right. americans are just retarded and can't into words

>>1296963
>That's no way to speak to your demented frail alcoholic mother u cheeky cunt
ftfy

>>1296983
I kinda want to see the current consumption of all that, once you decide where you're getting your "Vdd/2". CMOS gates are known to hog power when not solidly at one state or the other, but maybe the Schmitt triggers don't have that problem.
Also I thought part of the kawaii magic of the whole thing was that there were two pairs of light strings that wouldn't be perfectly in sync. Maybe use an NPN with base resistor on the low side of the complementary string for logic inversion.

>>1296994
>ICSP just something like
>just
It's an SPI interface that allows you to program/erase the chip fully, from scratch. AVRs you buy from digikey probably won't come with the lolduino bootloader so you'll need something like this to burn it on there. Also you can't change fuse bits and such through the serial interface, so can't get access to the config bits for clock control and such in case you would rather not add a crystal.
>bulk out
Nobody said you had to stuff the ISP connector. Put some test pads on the board. Use pogo pins or a card edge connector or some shitty improvisation along that line to hook up to them.

>>1297036
>demented frail alcoholic exploding mother
ftfy

Any EEs here? I need some help. The picture on the bottom is the small signal model for the top circuit. Can someone explain why they omitted R3? Was it an error? If it was can you redraw it cause I'm confused by the connection to the collector of Q2

>>1297060
I think since it's just about the input and output, the voltage at the Q1e/Q2c node is not necessary for calculating the rest of the circuit.

so how many of you are degree-carrying EEs?
How many just hobbyists?
What does a degree in EE teach you that you don't learn as a hobbyist?

>>1297036
>known to hog power
Indeed, see pic.
>>1296983
The charm of the original circuit is that it has two independent, slightly asymmetric oscillators that may or may not run in sync and can produce a more interesting (less boring) pattern. I would keep this circuit and just use some simple LDR circuitry on the common low side to switch it all on and off.

>>1296983
>>1297036
>Vdd/2
oh nm, I am derp, 4.02V was just a measurement point.

>>1297127
>not even all of a milliamp
indeed, the Schmitt trigger input helps reduce current consumption for mid-range inputs by a factor of about 5, vs. the CD4069, according to Pic related.

>>1295940
I know you said you don't know much about electronics but here is the service manual for your receiver anyway:
http://akdatabase.com/AKview/albums/userpics/10004/Pioneer%20SX3800%20Service.pdf

Those clicks are relays and the fact that they're clicking means they are probably working.

I'd look for blown fuses first. Look at the board layouts in that service manual land try to find things labeled "F1" "F2", etc, then try to inspect them on the actual boards.

>>1297060
If the lower circuit is the AC equivalent model, R3 is shorted by C2.

>>1297111
>so how many of you are degree-carrying EEs?
aye
>What does a degree in EE teach you that you don't learn as a hobbyist?
You can download the EE program of any uni and teach yourself the contents there. However, you won't have a tutor to help you when you can't undestand something and you will not have access to some instruments/tools the uni may have.

>>1297187
Wait, do you actually treat a capacitor as a dead short even though it will have finite reactance? Typically C2 will be a high-value electrolytic, but since it isn't listed I'm not sure if you're able to assume this.

>>1297184
Ohhh i see it now. Thank ya

>>1297202
If you tried to quote >>1297184, then, yes.
Thats small signal analysis for you.
In practice, you can follow this criteria: pick C2 such that its reactance is R3/10 at the lower frequency of operation of the circuit. This will, sort of, get R3 out of the AC analysis.
Its the same principle that makes Cin and Co dissapear from the AC equivalent circuit.

>>1296994
i can sympathize with home etchers because one of my elecrow boards has been lost in singapore for a month but i've never seen a diy pcb that didn't look like shit without an expensive setup

Does anyone here have experience using a soundcard oscilloscope like https://www.. zeitnitz.eu/scope_en ? I don't have a real oscilloscope at hand and i want to check the output of a circuit I'm building. Can i fry my soundcard if i don't attenuate my signal somehow?

>>1297235
You could put a pair of diodes in antiparallel at the mic input as protection. Also, mic input tends to be AC coupled by means of a capacitor, so you may not be able to see DC componenets of signals.

>>1297236
>you may not be able to see DC components of signals
Thanks for the heads-up. Maybe if know what my signal is i can use a multimeter reading to deduce whether i have a dc component or not? I want to filter out DC anyway tho.
Maybe I'll put some diodes then just in case.

>>1295940
>My old amplifier started acting up on me. It's a Pioneer SX-3800 from 1978. It turns on, but the LCD doesn't turn on. I used to hear the initial 'click' of the main power switch, then a second, softer 'click' as something inside turned on. I think whatever makes the second 'click' is what's broken, because I'm not hearing the sound anymore.

That extra "click" is likely op-amp DC protection / soft-start relay.

You need to check power supply and power amp board (DC offset / idle current) first.

If you have issues with the display you need again to start with voltage check on the display board (don't forget to check filament voltage).

Probably either some connector oxidized or trim pot took crap.

>>1296441
>where do you guys get breakout boards for SMT components so I can mount them on perfboard?
I don't use any break-out boards, just stick some kapton tape and slap the whatever you need on top of it.

http://elm-chan.org/docs/wire/wiring_e.html

For complex devices I'd rather make or order a PCB.

>>1297247
> still being a tripcunt
Opinion disregarded.

>>1295428
what i still dont get in electronics is that plus and minus is actually inverted, and electrons travel from minus to plus. and somehow scematis or lets say a transistor are labeled with plus and minus, too. anything that helps me understand?

>>1297250
essentially everyone's embraced a convention that is actually the opposite of physical reality simply because the convention was normalized before the physics behind it were fully understood. nobody other than physicists care which way electrons *really* flow, so if you see a current direction defined it's nearly always following the convention rather than reality (that is to say, the arrow is from high potential to low potential).

this is just more misleading but technically true shit that people spout, like "current kills you". i bet that one gets retards to touch high voltage things all the time because they're "low current".

>>1297250
Electrons. Blame Edison.
https://www.allaboutcircuits.com/textbook/direct-current/chpt-1/conventional-versus-electron-flow/

>>1297250
>>1297252
>>1297253
so in electronics, plus is "high potential" and minus is low/ground, right? and in every scematic you see the gnd everywhere and only the high potential wires are shown. but in reality we have that all the other way around---how does that work out?

>>1297253
nice read!

>>1297255
>so in electronics, plus is "high potential" and minus is low/ground, right?
right. and we draw current as flowing from high to low potential, while in reality the electrons are moving from low potential to high potential.
>how does that work out?
i'm not a physicist so i can't comment on how it impacts their work but in electrical engineering it doesn't matter at all as long as you're consistent in which direction you draw your arrows.

>>1297255
Plus sign is by convention high potential. Conventional current "flows" from high potential to low. Conventional current assumes that moving charges are positive.
However, in reality, current carriers are electrons wich have negative charge, so they must flow from negative to high potential.

>>1297257
i think the key is, that actually everything is inverted. so if every plus and minus symbol is inverted from the physical truth, but we use that plus now as the actual electron source, it works again. am i somewhat on the right way?

>>1297258
>>1297259
ok it makes sense, either we say by convention electrons are actually positive or that i imagine everything is "inverted" is the same thing. btw im actually samefagging all the time

>>1297260
Electrons have negative charge, no need to invert anything.
Conventional current (the one that goes from plus to minus) was assumed to be made of a flow of positive charges. However, in a real physical circuit, the only moving charges are negative (electrons).
So you have to ways of viewing the current in a circuit:
1- The "real" physical way: electrons flow from low potential to high potential. This is sometimes called electron current.
2- The conventional way: positive charges flow from high potential to low potential. This is called conventional current, and was derived from the fact that early electricity investigators assumed that current carriers had positive charge.

>>1297267
i think im not getting it.
are the electrons actually flowing in the direction indicated by the red arrows to gnd or not?

>>1297236
>>1297238
Mic input tends to also be configured to bias an electret mic element. Consider a line-in if the ac part of your signal is large enough.

>>1297272
No, you have drawn conventional flow. Electron flow is the other way.

>>1297246
>>1296052
Oh, hey, our special snowflake tripfag is back, as ignorant about his faggotry as ever. What did we do to deserve your absence, and how the fuck do we do it again?

>>1297274
>line-in
Ohh ok I get it, completely forgot about the line-in jack. Thanks anon.

>>1297272
>>1297274
ok so i assume e flow is like indicated by green arrows, and thus the transistors "get electrons at their base" from GND, allowing electrons to flow from Emitter to Collector and finally to PLUS?

>>1297272
positive attracts negative
electrons flow towards the positive terminal(s)
this is why the hydraulics model is flawed and not used past the very basics

>>1297281
Bretty close, except for the transistors. Pic shamelessly ripped from le wiki.

>>1297287
pirating pictures from wiki, eh?

ive drawn how i understood it, is it correct?

>>1297295
Arr you betcha matey.
Remember, hole flow aka conventional flow is the opposite of electron flow. So electrons only go into the emitter in an npn transistor. A few go out the base to Vbe, as they do in a diode, and several times more enter the base and are pulled toward the collector due to the positive charge at the B-C junction.
The bipolar junction transistor article is pretty good and worth a read, not least the "Note on current direction" :^)

>>1297299
>So electrons only go into the emitter in an npn transistor. A few go out the base to Vbe, and several times more enter the base.

isnt that kinda contradictionary to the picture?

there the white arrows (i suppose these represent electron flow) point towards emitter and Base, whereas you say that the big white arrow should be pointing the other way (A few go out the base to Vbe)

>>1297303
Holes are electron-deficient spaces in the silicon crystal that electrons can be pulled into, and can move around much like electrons. White arrows in the transistor are hole flow, as labeled. Grey arrows in the transistor are electron flow.
Note that the arrow on the base terminal in the circuit outside, representing conventional flow, points into the base. Electrons being pulled out of the base create holes in the base, which flow toward electrons in the more negative part of the transistor in an effort to be filled.

>want to make small, uncomplicated beginner stuff with the components I have
>all the "beginner electronics projects" require components that I don't have, take a while to ship, and are prohibitively expensive to ship
I just want to learn but I can't :(

>>1297318
I should amend:
>or use an arduino
I don't want to use an arduino, it feels like cheating

>>1297283
>positive attracts negative
negative attracts positive :|
>hydraulics model is flawed
pressure & flow model is reasonable
there's a chemical 'pump' in the battery

>>1297187
I was more wondering, what separates an Electrical Engineer from a proficient hobbyist?

>>1297127
>some simple LDR circuitry

>>1297321
Two decades ago it was employability in their field.

>>1297320
>>1297299
>>1297267
>>1297257
>>1297258
ok thanks guys, my confusion is more or less gone

>>1297327
elaborate?

>>1297127
This is a very good point. Having perfectly synchronized oscillators wouldn't look as nice. I separated the LED strings into two groups, each driven by its own oscillator. The second oscillator produces a slightly lower frequency to ensure proper de-synchronization. This configuration also leaves one NAND gate unused, not sure what to do with it. I might just tie its both inputs to GND.

I'll breadboard this circuit even though in the end it may not be worth to build it.

>>1297322
Are the switch devices in your picture FETs? They do not have any arrow symbols (N-type, P-type) but I suppose they are N-type as their emitters are connected to ground.
Driving the LED strings with FETs might be a nice idea as they would not need a constant base current to turn on. Are there any equivalent FET devices as 2N3904/2N3906 or BC547/BC557?

Which analog soldering station should I get given that buying used is not an option? Preferably something like the good old Hakko FX-888 in terms of price and quality.

>>1297367
>suppose they are N-type
Yes, both N-type, source = ground, 2N7000 or BS170.
>equivalent FET devices
BS170 (N), BS250 (P)

Don't let unused gate inputs float.

>>1297367

this looks like a lot of wasted effort.
- replacing the transistors with a chip saves you maybe 1% in energy, since almost all of the energy is used by the bulbs themselves.
- you can just add the LDR circuit externally which cuts down your work by 90%
- or you can snake a transformer wire to the ckt which cuts your work by 95%
- or you can replace the 9V with 2 Lipos, which will work for days on end, and cut down your work by 97.3%
- the 220K's in the bases of your transistors need to be lowered to about 5-10K

>>1297321
Depends on what you mean by proficient hobbyist. If you mean someone who knows analog design and how to use an arduino, it's a more theoretical understanding of how electronics work, and how to use the underlying principles in truly novel ways.

what do you all use to model circuits?
a cursory search turned up "qucs" as a FOSS solution, but is there something better?

>>1297441
multisim is free but closed source. it works as well as anything with an interface straight out of 2004 can be expected to work.

>>1297441
LTSpice. Free, easy, quick

>>1297373
Very little choice. Clone is much, much cheaper. Don't know about quality.

>>1295428
hey /ohm/, just curios as to what resources i would use if i wanted, lets say, a catalog of all electronic device available for purchase?
Trying to built something for a little project, but don't know where to find a specific component. Also a general catalog is very useful for /diy/ projects so it would be very helpful of you if you could be so kind.

This is the simplest electronic circuit of all.

>>1297479

read the sticky: ''In the US and elsewhere, mouser.com, digikey.com, arrow.com, newark.com are full-line distributors that entertain small orders''

these websites list pretty much everything you can buy in the world of electronics.

>>1297488
captcha welcome welcome

>>1297479
There's an absurd amount of them.
You can get some limited idea just by going through the catalogues of the well-known suppliers like Digikey, Mouser and Farnell. They list hundreds of thousands components.

I'm trying to simulate the operation of 74HC194 with Logisim. I found its logic diagram from an NXP datasheet but I'm having some difficulties getting it to work.
The data sheet mentions:
>The synchronous operation of the device is determined by the mode select inputs (S0, S1). In parallel load mode (S0
and S1 HIGH) data appearing on the D0 to D3 inputs, when S0 and S1 are HIGH, is transferred to the Q0 to Q3 outputs.
>When S0 is HIGH and S1 is LOW data is entered serially via DSL and shifted from left to right;
>when S0 is LOW and S1 is HIGH data is entered serially via DSR and shifted from right to left. DSR and DSL allow multistage shift right or shift left data transfers without interfering with parallel load operation.
>If both S0 and S1 are LOW, existing data is retained in a hold mode.

However, if I first set S0 and S1 high and set any of the data inputs high, all outputs are set high after a clock pulse. Pic related, situation after low->high clock transition.

Can anyone spot any errors in my simulation model?

>>1297283
>the hydraulics model is flawed
If you can imagine holes travelling in the opposite direction to the electrons then you should be able to imagine anti-fluid doing the same. Sure the analogy probably doesn't work for transistors, but for passives, especially LCR circuits and Thevenin equivalents it's perfect.

>>1297373
Why would you ever want an analog station instead of a digital one?

>>1297503
This might be a stupid question but are you triggering on the correct edge?

>>1297492
>>1297489
ok cool thx.
If i have any trouble finding a specific component i'll come back here.

>>1297503
Replace the 3-input NANDs with ANDs.

>>1297512
>>1297517
Thanks guys. I found that Toshiba's datasheet had a slightly different figure. I tried it and it works like a charm.
There's something strange with NXP's datasheet. maybe it should be reported to them.

>>1297530
Typos happen. It shouldn't hurt to report it.

>>1295428
>Getting Started in Electronics Forrest Mims III
This right? https://www.scribd.com/doc/19963886/Forrest-Mims-III-Getting-Started-in-Electronics-Radio-Shack

Trying to pirate this shit so i can have a resource to use.

>>1295428
Hey senpai, while rowsing for free downloads of books i ran across this beuaty:
http://www.engineeringbookspdf.com/
Its an entire site of free downloadable books on different topics of engineering. Pretty neato if you're interested.

>>1297530
EE noob here, why the double NOT ports on the outputs and some of the inputs? Is this some sort of line filtering?

>>1297503
Replace the total ohmage impedance of S3, like in Q0

>using hot air gun on soldering station
>notice lights flickering
>breaker blows
>look at holographic sticker on front


BAMBOOZLED YET AGAIN

>>1297595
Buffering I believe

>>1296994

Serial programming is done thru the MOSI/MISO/SCK/RESET pins on the device, it's not something you hook some generic usb-to-serial chip to, it's something you'd use an avr isp programmer with.
The STK500 has a 6pin header for ISP, the AVRISP mkII (cheaper) will also work.
Google AVR ISP programmer, google avrdude, google atmel studio, there's a bunch of cheap devices out there.

There are also arduino-based isp programmers I believe.

Lots of ways to skin this cat. Personally I use my STK500 and I've had it over 10 years.

I am a literal child rapist.

I'm trying to understand power supply design, this is from a book:
>a dc-to-dc converter is used primarily just to change a voltage level. This could be done with a non-isolated linear or switching configuration or, in many cases, with an interstage transformer which can add safety isolation as well as voltage-level changes. In this form, a DC to DC supply will actually be a DC to ac converter to drive the transformer at some high frequency, followed by an ac to DC stage to deliver the required output.
So, why do I want to drive a transformer at high frequencies? Also, is it necessary to go between ac and dc so many times? Is there not a practical way to take the line power ac and make it high frequency without dc conversion?

>>1297708
other than cleaning up the noise, the part I circled in red seems extraneous/unnecessary.

>>1297708
>So, why do I want to drive a transformer at high frequencies?
The resulting transformer size is lower that way
Also, is it necessary to go between ac and dc so many times?
Yes
Is there not a practical way to take the line power ac and make it high frequency without dc conversion?
No

https://en.wikipedia.org/wiki/MOSFET#Modes_of_operation

Why is the Vds<Vds(sat) region called "linear?" It's clearly quadratic. Wikipedia says "the MOSFET operates like a resistor," and I can't wrap my head around what is meant by that.

>>1297720
Whatever you think is quadratic (probably the red line in that graph) is not what is meant by linear.

https://electronics.stackexchange.com/questions/76071/meaning-of-mosfet-linear-region-in-the-context-of-switching-losses

I'm talking about the blue lines, particularly in the "linear region" where the drain current doesn't increase linearly with Vds, as dictated by the second order Ids equation (quadratic).

So from reading your link, it seems like it's just imprecise terminology. Power electronics guys can eat my ass.

>>1297708
>>1297710
>the part I circled in red seems extraneous/unnecessary.
It isn't, every AT/ATX power supply you've ever owned used high frequency switching in order to reduce size/weight and increase efficiency.

Try to design a power supply that chopped up your wall power into high frequency AC without an ac/dc conversion beforehand. If it was easy or practical, every power supply would be done this way, but they aren't.

>>1297720
>Why is the Vds<Vds(sat) region called "linear?" It's clearly quadratic.

Generally there are cut off, linear, saturation regions. In real world cut off is oversimplification as there still would be some current (albeit extremely low for non-germanium transistors / not when junction is at extreme temperature), linear region is linear enough for small signal analysis and generic calculations for bias point /etc.

> Wikipedia says "the MOSFET operates like a resistor," and I can't wrap my head around what is meant by that.

You can model drain/source channel as a voltage controlled resistor or a current source. Current source is what is usually used for linear region.

>>1297741
>where the drain current doesn't increase linearly with Vds, as dictated by the second order Ids equation (quadratic)
Thats because in that equation Id is a function of Vgs, not Vds.

>>1297595
>>1297632
Yeah, it's buffering. Without the double inverters in the S0/S1 inputs you'd have to drive 9 gate inputs instead of just 2.
Buffering also makes the input logic levels better defined (more gain makes the transition snappier). This in turn makes the inputs more tolerant to slow edges and reduces the cross-conduction current when the input voltage.
The outputs are also buffered.

>>1297796
... when the input voltage is between the high and low levels.

So, I know fuckall about electronics and I would like to get a wall adapter for my old walkman. I can solder but I couldn't design a circuit if my life depended on it. it's the standard barrel jack but 6v, center negative. can't find them to buy with the EU plug and 240V anywhere. Should I just get a variable bench supply and hook it up, or are there any neat shortcuts i can take?

>>1297802
There are adjustable adaptors that come with many (reversable polarity) plugs.

>>1297796
Thanks! I've had a few intro EE classes which covered a lot of stuff, but for whatever reason buffers were never explained. They always just said "oh yeah that component doesn't do anything, ignore it." The joys of EE classes for IT majors.

>>1297808
Neat, thanks. Surprised I didn't find these in my searches.

>>1297708
your question has been answered but you may be interested to know that the mains side "ac to dc" conversion before the high frequency switcher in some types of converters (flybacks generally) is just a bridge and a very small capacitor, so it can be very cheap to implement and you're not getting much out of somehow managing to do mains AC to high frequency AC.

on the other hand some converters need large, relatively expensive capacitors after the bridge because they can't accept large dc input voltage fluctuations but that does carry the added benefit of letting the supply run during brownouts.

>>1297627
ah qenuine guality enqineerinq

Guys I need some ideias... I need an amplifier/signal conditioner for an piezo accelerometer that will be subjected to low frequency vibrations. I was thinking about using an charge amp with a low pass filter but dont know if it will work. I cant buy it ready I need to build one

I have all the requisite tools needed to get into electronics, a decent solder station, desoldering pump/braid, good solder and flux, a nice multimeter, boxes of wire, etc, but I've only ever used it for the repair side of things, so I've never really learned anything. I've got an idea for a small project, I'm just curious if it's one I gotta go deep down the rabbit hole for, or if it's a good simple first project. I just want a small light-up 3 digit display, maybe 1-1.5" wide, with 3 small dials or sets of buttons to let you adjust each number up or down, using whatever battery isn't going to make me regret choosing that battery. Something that'll last decently long and then not be too spendy to replace, because I want to make a few sets of these, at least 20.

Is this something where to do it well, it's actually going to take some learnins, or are you all reading thing and thinking "You can do it well by just getting a 10 position dial, a cheap display, a AAA sled, and a 1.5v->3v converter thing you fucking retard"?

>>1297962
You could if you wished do this with logic, 4000 or 7400 series, some bcd counter and segment drivers simple enough but interesting to start, or you can do it with a microcontroller either directly multiplexed or get a segment driver ic and talk to it.

Usually when your learning you follow a few projects and pick up the ideas then know already the principles

>>1297963
What would the advantage be for the logic versus purely mechanical?

>>1297963
What would the advantage be for the logic versus purely mechanical?

>>1297953
Charge amps certainly work in that application, but piezos generally become increasingly difficult to use as frequency goes down.

>>1297969
>>1297969
Thats my worry but the problem is that I will need to use pizos. Any ideas in how to avoid low frequency gain and other problems?

>>1297964
If by "purely mechanical" you mean battery + displays + switches + resistors, then either the displays are very clumsy to set (one switch per segment, 21 in total) or you need expensive BCD input displays and BCD output switches.

>>1297971
There's no magical solution. You just need bigger and bigger feedback resistors and amplifiers with lower and lower bias current. You can also sacrifice noise performance for lower cut-off frequency by increasing the feedback capacitor.
Obviously a piezo with bigger output will help.

>>1297973
>bigger and bigger feedback resistors and amplifiers with lower and lower

you might know what you are talking about, but this is not the way to state it.

I'm not hating. I'm your middle school english teacher who liked you in spite of your retardedness.

>>1297971
http://www.linear.com/solutions/5969

>>1297990

wow, 1 giga-ohm feedback resistor!

I'm trying to create a mini desk fan from an Intel could fan but even though the fan is rated for 12v 0.3A it only pulls 0.1A from my boost converter. I've tried 2 different boost converters that should both be easily capable of providing 0.3A at 12V, mt3608 and xl6009.

I've also tried running the fan at 13v instead of 12v but there's no increase in current.

I also have another one rated for 12v 0.6A but that's also only drawing 0.1A

How can I get the max rpm/airflow out of this fan?

>>1298057
Intel CPU fan*
Stupid auto correct...

>>1297962
Well I'm using an Arduino to turn my 3-digit (measured temperature) value into some 7-seg + adjust-LED serial list and feeding that out through a single output into three 74HC595 latching shift registers, plus a clock to shift all the inputs through the three registers and another 1/24th speed clock to latch them all every full cycle. It's not going to be easy to program, but it's the method that takes the least amount of ICs and output pins.

For your purpose using a micro isn't terribly desirable, but it isn't all too expensive if you go with a knockoff. I'd personally see about doing it with a bunch of flip-flops to make a set of frequency dividers for each digit, plus some logic to get them to overflow from 9 to 0. That takes 16 flip-flops all together, so your best bet is 4 74276 (or something similar) quad flip-flops with seperate clocks. What can I say, I'm a sucker for the 7400 series. Note how the three animated flip-flop outputs count upwards in binary (from left to right). Then use any old NAND/NOR IC to implement the return condition, and put whatever BCD to 7-seg IC on the output of each digit. Figuring out how to count downwards might be difficult, but you can mess around to no end in Logisim until you figure something out.

Read up on basic logic gates (xor/xnor is optional, nobody uses them anyway), boolean algebra, Karnaugh maps, latches, flip-flops, and maybe shift registers.

>>1298065
Oh yeah, and propagation delays in logic gates and timing diagrams are also something to look up.

>>1298057
>could fan
maybe it's a can't fan. if it's flat on the table it runs at no load. don't block air flow, let it fan.

>>1298057
Hey dummy, show us what you're using to set the speed.

>>1298077
>set the speed
Nothing, I'm just connecting the positive and the negative wires to the boost converter directly.

It's a 4 pin fan though so I'm assuming the other 2 wires have something to do with fan speed?

I'm working on the code for pic related.
Basically an ultrasonic sensor mounted on two 180 axis. Will output distance data via serial port (SD Card) in the future to create a rough cloud point data set.

A C# script within unity will then smooth this out and create a 3D surface representation.

After that if I'm not bored, I'll mount the thing on a rover chassis and create a smart room navigation system. Where a drone rover will go in to an area, map it, figure out rooms/entryways, and will be able to autonomously navigate within in it.

>>1298083

>>1297441
ngspice is good. Proteus is nice for simulating avrs and other mcus.

>>1298083
Tie the blue wire to 3.3-5V, that might help. The following wiring diagram might help. By feeding a 0% duty cycle to the PWM pin you're probably having the thing run at it's minimum speed.

>>1298118
Dehe!

Had a dead boost converter, mt3608, used the dead one to add a second parallel ss34 to a working one.

This should theoretically improve efficiency and output current, right?

When tested it was always the ss34 that was the hottest. I'm not expecting double the performance, but would it increase performance at all?

>>1298139
It won't decrease, assuming those are diodes. Performance should increase a small amount.

>>1298118
>By feeding a 0% duty cycle to the PWM pin you're probably having the thing run at it's minimum speed.
i'm not going to argue because i don't know but thats a dumb system.
failsafe would be not connected == maximum speed

>>1298172
>failsafe would be not connected == maximum speed
That would be a good feature, but for a fan that isn't running at peak speed I don't think that's something we can infer.

>>1298139
Lower current -> lower forward voltage -> lower power dissipation, but you're operating on a steep portion of the IV curve so gains are minimal.

Can I make a 2-way optocoupler with 2 normal optocouplers?

>>1295884
Not sure if this is a legit question or just a stupid joke

>>1298230
>>1298166
That's fine. I'm happy with a small gain, it's better than wasting a dead board.

Thanks.

>>1298273
Well if you ever do SMD stuff then having an SMD diode lying about wouldn't be a waste at all, but getting all your SMD components from old boards isn't terribly realistic. I hope you harvested the inductor and trimpot off the old one though, provided they're intact.

living in australia what would be the best gauge wire to replace the wires of an industrial vac?

Why do you guys spend so much time and effort taking components off junk boards instead of buying them?

say i have a drill or something, how can i determine its amp load?

do you guys use ohm meter for this stuff?

assuming its not written on the drill itself

>>1298277
I got the inductor off it. I don't normally do smd stuff but I'm going to be starting soon.

>>1298279
>Have dead board
>Pull component
>Can use instantly
>Recycling is a good habit as you're generating less harmful waste

>Drive to store
>Buy parts in bulk packs because muh value
>Drive back and use one
>The rest just sit there and rot

>>1298278
34awg or 36 awg.
The higher the gauge the better it is as it can carry more current.

>>1298282
Or, join the 21st century and order the parts you need plus a spare or two off digikey.

>>1298282
> have dead board.
> pull component.
> spend 20 minutes wondering what the fuck you have done wrong with your prototype because it is not working as designed
> realise the component you pulled is the one that killed the device you pulled it from.
Bitten more than once by this early in my career, aaaand pass thanks. My time is worth more than a junk.

> burn fossil fuels/money on a drive instead of letting someone else sink that cost.
> be an arduinofag who does one project then puts it all in a cupboard because you have no imagination
> be too stupid to realise you buy common value packs instead of ALL THE VALUE packs
I can honestly say there is nothing in my parts bins more than 12 months old. Glad to see you are so open about how dumb you are though.

>>1298279
Though I can't exactly speak for everyone, typically only beefy transistors, big electrolytic capacitors, inductors/transformers, and other rare or high-power/voltage parts are all that's worth getting off a board, certainly not everyday resistors or ceramic capacitors. And typically buying parts means waiting a while for shipping, so it means you have to either just buy an excess of parts for general purpose stuff, or buy specific parts for each project in advance. The first method is fine for cheap stuff, but you don't go out and buy 20 105C 1000µF caps you're going to blast through your savings. A compromise is to always buy extra parts online, and that certainly helps.

>>1298281
Unless it's a resistor, you'll have to use an ammeter while it's running. For a cordless drill it's pretty easy with any old multimeter, but for a corded one you'll need one that can handle AC current. A current shunt and a voltmeter works too.

>>1298283
What the fuck.

>>1298118
>By feeding a 0% duty cycle to the PWM pin you're probably having the thing run at it's minimum speed.

that's not how it works. if the PWM pin is open, fan will run at 100% speed. this makes it compatible with older 3-pin connectors on the motherboard.

>>1298256
>Can I make a 2-way optocoupler with 2 normal optocouplers?

there's no such thing. if you mean ''can a replace a dual with 2 singles?'' then yes, of course.

>>1298283
>34awg or 36 awg

you jokin' mate? 34awg is tiny like a hair. 24awg is more like it. also, it's the other way round: smaller values equal larger wires. even in upside-down australia, home of Josef Fritzl.

>>1298289
>Bitten more than once by this early in my career,

ok, you've been around long enough to refer to your "career".


>I can honestly say there is nothing in my parts bins more than 12 months old

BWAHA AHAHA AHAHAHAHA AHAHA AHA AHHHAAA

that was a good one, son.

>>1298302
I was actually wanting to make a single optocoupler out of two in parallel that can be used in both directions, input and output. But I'm worried I might get a positive feedback loop with it, like pic related.

>>1298282
>have dead board
>spend as much energy removing it from the board as you would have buying new
>spend as much time testing the component to get its value and make sure it's not dead
>win???

>>1298312
Indeed, that's a problem. You might look into how I2C buses get around that sort of thing, such as the P82B96 buffer datasheet.

Can someone explain to me what it means when people say capacitors act like short circuits?

>>1298355
... at sufficiently high frequencies.
The impedance of a capacitor goes down as the frequency goes up. At some point the impedance is low enough to be seen as a short circuit. 10% or 20% of the other relevant impedances is often "low enough"

thoughts on this guy?

who cares

Why is the voltage drop so huge on the mosfet? Rds(on) is 0.018 ohm.

>>1298395
Maximum knowledge, I like him even more than louis rossman. He's not really as entertaining though.

How much electrical power could be extracted from the heat produced a small ordinary candle? Let's say the candle is placed in a lantern and the outdoor temperature may range from -25 °C to 0 °C.

>trying to decide if I should make a spot welder for making a couple small 18650 banks
>check youtube
>the people saying you should use a spot welder have absolutely no fucking idea how to solder
>the people saying you can solder also don't know how to solder

>>1298409
Thing is. I need a relay for 9v and still want to use the same 9v battery for powering the circuit. The mosfet voltage drop is just way too big. Any ideas?

>>1298424


(mass of your candle*Calories per gram of parrafin)/Time taken to burn a candle.

Thats your power rating right there.

I'm relatively new in electrics and robotics but a long term goal of mine is to build a humanoid robot. (Yea i know it will take a couple of years to make one.) The first step will be something like one of these bomb disposal robots the American soldiers use. I'm planning for ~10-20kg.
That being said i'm trying to pin down types of motors that are:
>relatively cheap
>(1) may be used in a blocked state - for gripping things, and maybe later more sophisticated limbs
>(2) high torque main motor for robot movement
Right now i'm considering getting a few wiper motors from a local junkyard because they have been used for other projects, and maybe the motors used by electric wheel chairs for the main wheels, any other ideas for economic motors?

>>1298443
Take apart old scanners and printers for stepper motors, axles, gearboxes, all sorts of good stuff.

>>1298435
Use common source rather than common drain configuration. Move load to drain and connect source to ground.

>components arrive
>sniff them
>they smell like cancer
Not sure what I expected really

>>1298424
Candle power 80W
TEG efficiency 5%
Other losses 50%
Power out 2 W

>>1298445
>scanners and printers
>stepper motors
TRY AGAIN

>>1298258
Nah, messing around, I ordered the fuses the day before I posted. The clamp meters and an 87-III and 87-V are mine, the 179 and one 87-V are other people's. I know folks who work at Fluke, so I got deals. Free 87-III when someone upgraded, clamp meter from the scrap bin(one setting only works intermittently), 87-V with a dead mA mode that we're pretty sure is just a fuse for $90.

>>1298460
Like this?

>>1298671
Yes. Is that not the response you're looking for?

>>1298717
Just wanted to make sure. Thank you

>>1298671
You can bypass having to say "PULSE(0 9)" and instead just use a DC source by putting ".tran 0 60 startup" as your SPICE directive. The startup part means that all voltage sources start at 0, but the ramp-up time is a few µs so you can't use this if that ramp-up time matters significantly.

>>1298425
i soldered a 10s4p out of samsung cells
i had to take breaks and use a fan to keep the heat down
> would not recommend

Can anyone reccomend me a good wifi LED light bulb? I've generally stayed away because of PWM flicker on LEDs.

>>1298818
Make your own? If not I think the western/Japanese brand-name ones are bound to be good, like Philips.

Can I use an Attiny85 to read a TV remote signal using a demodulator sensor (those 3 pin IR sensors) and modulate the signal again and send it to the TV to act as a range extender for a remote?

I've tried this with a 555 with poor results. I think my Chinese CMOS 555s are just regular 555s.

>>1298634
https://youtu.be/mSU-GeEe0P0

>>1298634
Cheap printers will have DC motors with an optical disk thing to provide feedback, old and more expensive ones will probably have steppers. I've even found stepper motors in old hard drives.

>>1298841
>$10000 office copier
Okay.

>>1298844
Yeah, stepper was the standard solution in very, very old HDDs (30MB or so). Ye olde 5.25" floppy drives also had usable steppers. Then the HDDs switched to linear motors and the floppy drives to nearly useless mini steppers.

>>1298840
>CMOS 555s are just regular 555s
Find out by measuring R between pins 8 and 5. 555 has about 5 K, C555 has >50 K. IR repeater can be done with either if you do it right, C555 preferred because much less 'crowbar effect'.

>>1298840

it makes no sense to use a micro-computer to do something which requires zero computing. you just need to toggle a 38Khz or 40Khz waveform on-off depending on received pulses. that requires no intelligence at all: no memory, no decision tree.


fix your 555 ckt before abandoning it.

>>1298840

it makes no sense to use a micro-computer to do something which requires zero computing. you just need to toggle a 38Khz or 40Khz waveform on-off depending on received pulses. that requires no intelligence at all: no memory, no decision tree.

fix your 555 ckt before abandoning it. try a diff one. measure your frequency.

I found this little guy at Goodwill for 5 bucks. I replaced the obliterated insides with a pam8403 module I designed on easyeda that has a 3.5mm line in, a sound reactive led circuit for that plexiglass saucer on the front(with an electret microphone), and a Bluetooth unit. The amp module only has one input, and I didn't install a source selector. Should I be worried about the Bluetooth unit when I have something plugged into the line in?

what's the technical term for a pitch-bend potentiometer?
AKA, a potentiometer that returns to the center very quickly by itself after being flicked up or down?

>>1299039
Alright so I disassembled one of my old keyboards real quick, it turns out they just spring-loaded the knob.
Very creative. I'll probably just wind up using this one with a smaller cap.

>>1299048
>>1299048
>>1299048

>>1298863
Yup, 6k, I got chink'd. I'll try a 4046 Schmitt trigger as an oscillator.