/diy/ - Do It Yourself

>order boards from elecrow over a month ago
>order other boards from oshpark last week
>both arrive at the same time
>oshpark boards came with a bag of jelly beans
this is the difference between buying american and buying chinese. too bad purple boards get old quick.

>>1299085
man, all I got was a sticker
purple boards do get old quick, for sure
otoh, oshpark boards seem to be a lot harder to delaminate than some of the commercial ones I've abused

>>1298840
Can't you just use the incoming signal as the oscillating signal in the first place? If the IR will be flashing at 40kHz then just use the phototransistor to power another IR LED, provided phototransistors can act that quickly.

>>1299176
Re-invent the wheel? Using a ready-made IR receiver to modulate a simple transmitter is much easier.

>>1299045

same principle used on racing-wheel controllers, they use 2 bits of bungee cord to return the wheel to center.

>>1299176
Tuning is important if you don't want to get swamped by dimmers etc.

>>1299283

and more important still is the AGC which allows the thing work with signal levels that can vary by 1000-fold. that's hard to duplicate.

>>1299201
My point is that you shouldn't have to use a demodulator at all if you're transmitting the same signal you're receiving.

>>1299283
Dimmers?

>>1299309
That's true, but surely as long as you set it to activate on all signals except those from the ambient sunlight there shouldn't be a problem, right? I can't imagine you'll ever run into the problem where the IR background noise's maximum amplitude is higher than the IR signal-to-be-relayed's minimum amplitude. And even if this does happen, a DC-blocking capacitor (and maybe a differentiator) should sort that out.

What I'm more worried about is whether you'd get duplicate signals to the original receiving device; one from the original transmitter and one from the relay. But AGC isn't going to fix that.

>>1299340

i dont think you quite get the picture about the importance of the AGC in terms of a simple IR repeater without a decoder.
suppose the remote is far away and your detector only receives a 5mV signal. without a proper AGC, then it ends up repeating that signal by sending out a 5mV signal to the transmitter LED. and 5mV isnt gonna go very far.

a decoder with AGC in it will fix that by re-transmitting anything it receives, whether large or small, at the same amplitude.

>>1299416
>sending out a 5mV signal to the transmitter LED
Just run the LED off a comparator with a 1mV or so divider to set the cutoff region. Though I thought IR receivers would be closer to a current source. I was assuming that the phototransistor itself would amplify the signal enough to power the LED, but I guess just putting a resistor in there isn't a very good way of filtering out IR noise.

>>1299176
Hi, I'm the guy from the other thread. Aconditioning the signal coming from the IR photodiode is a harder than just connecting the output of a demodulating sensor to an oscillator. I've tried it before and the photodiode's reception is very weak when used on a voltage divider, so that means using one or two amplifiers, filters, comparator...

>>1299422
If the photodiode works more as a current source you should be able to just pass it through an NPN or two, with appropriate resistor to keep it in the linear region and give a worthwhile output signal.

But if they are much more like a photovoltaic panel, I can see why this would be a problem since the mV won't activate the transistor much at all, but unless the AGC+filters+demodulator all come in a nice and easy to use package, I don't think a dual op-amp chip would be inefficient space-wise, since it can handle amplification and the cutoff voltage.

>>1299428
>unless the AGC+filters+demodulator all come in a nice and easy to use package

they do. and they're free coz you pull them from kinds of dead gadgets that use a remote (stereos, DVD players, cable boxes, VCRs, etc). i pulled this one yesterday. 3 pins: ground, 5V, digital signal out.

>>1299421
>just putting a resistor in there
Do you have any practical experience in the field? How do you deal with the optical noise generated by a CFL screen background and fluorescent lamps running on electronic ballasts? Suppression of such signals is part of the AGC/demodulator circuitry. A naïve 'why don't you simply' approach can quickly accrete a substantial BoM without solving real world problems.

Seeing as this is the Atari punk edition I have a couple of ohm music related circuit questions.

I have built a couple of sequencers, a pulse generator and a multi vca’s from kits. The two sequencers seem to be acting a little bit differently to each other, one channel on the vca isn’t working at all and one of the 7 pulses isn’t working.
I’m a totally new to the electronics side of this and would like to understand how to trouble shoot these circuits. I think I could probably work out a basic schematic by now to understand which components are where, but I really struggle with it once it’s on the pcb.
The pulses module seems to be the simplest module so I’ll start with that. It has 7 pulses coming from a 4081IC followed by a couple of resistors a led and a 3.5mm output socket. Some of the outputs are AND I believe so maybe not coming directly from the IC?
I have a basic digital voltmeter and an old oscilloscope and although I’ve used them both briefly I have no idea how to use either to test a circuit.
Please help!

I think (pic related) is the schematic for the pulses module?
Pulses info is on this page here:
http://musicthing.co.uk/modular/expanders-for-the-turing-machine-random-looping-sequencer/

>>1299482
You can test the following with your DMM or scope:

bit1 appears on out1 and on pin 8 of the 4081
bit2 appears on out2 and on pins 1 and 9 of the 4081
bit4 appears on out3 and on pins 2 and 12 of the 4081
bit7 appears on out4 and on pin 13 of the 4081

4081 is a quad 2 input AND gate
+12V at pin 14, GND at pin 7

out5 is bit1*bit2
if one bit is 0 out5 is 0
out6 is bit2*bit4
if one bit is 0 out6 is 0
out7 is bit1*bit2*bit4*bit7
if one bit is 0 out7 is 0

A first quick test would be to set all bits to 12V and see if all LEDs come up.

2.1kΩ resistors are not common
the standard value is 2.2kΩ

>>1299445
For a low (optical) noise environment it is possible to build a pass-through IR repeater using a special IR sensor version made for code learning remotes. The advantage is that it works from 30 kHz to 50 kHz and supports all data formats. The circuit depicted can be modified to realize a stand-alone, battery operated repeater that runs on 3 AA cells or even a single LiPo/Li-Ion cell.

A few dumb questions, if you dont mind

1) What happens in an AC circuit if you were to have one lightbulb hooked up to the circuit normally (primary to primary, neutral to neutral) and then another bulb hooked up on both terminals to the neutral (primary to neutral, neutral to neutral). Would the second lightbulb work? What would be different?

2) In somewhat simple terms, why is it that some types of loads only "draw" as much power as they need in an AC circuit? Why dont they "accept" all the power that is available to them? In other words, if you have one lightbulb on a 15a circuit, why isnt it running on like 1,300 watts?

>>1299537
>Why dont they "accept" all the power that is available to them?

Because every load has a specific amount of electrical resistance. Resistance restricts the current flowing through the load.

>>1299514
Hey thanks for the reply.
>You can test the following with your DMM or scope
How do I go about doing this? I’m guessing I need to power the module up and then probe about the points you mentioned? Where does the ground go from the scope does it need to go to the ground on the module, if so how the hell do I get the croc clip onto a ground pin?


>A first quick test would be to set all bits to 12V and see if all LEDs come up.
Yep they all light up when attached to the main module and the corresponding steps are lit there. Pulse 2 led is always on regardless, but it didn’t seem to be putting out any signal from the jack.

>2.1kΩ resistors are not common
the standard value is 2.2kΩ
Looks like mine are 2.1k (red brown black brown brown)

>>1299558
But then how come you can change the resistance without changing power delivered?

>>1299537
>live and neutral
Neutral stays at 0 volts (ideally, in reality you have some voltage due to resistance on the wires and other factors) and live changes voltage sinusoidally from 170 to -170 volts (if you're using 120V AC), current flows into the lightbulb forwards when the voltage is positive and backwards when it is negative. When the voltage passes through 0 there's no current. You can see the incandescent filament glowing brighter and dimmer with the current if you have a slow motion camera.
>neutral and neutral
Both neutrals are at 0 volts, so the lightbulb stays off.
Neutral wires are usually connected to ground at some point in the electric grid.
>why they don't accept all the power
If I have a pipe capable of delivering 1m3 of water per second and put a small opening in the pipe I can get a much lower flow. The same happens with electricity, if you use a 100W lightbulb on a circuit that can deliver 1300 the lightbulb will only draw 100W because it has the right resistance. Voltage/current = resistance. The lighbulb manufacturer makes filaments of a certain resistance to achieve a certain current and thus a certain wattage.

Watch several videos on Ohm's law. There are also certain kinds of loads which don't behave linearly and depend on the frequency, if you want to know more watch some videos on inductive and capacitive loads.

>>1299571

So what if you had a split or multiple phase system, with different loads on each phase. Then would connecting only neutrals light the bulb?

>>1299561
>how the hell do I get the croc clip
maybe the gnd side of one of the 2.1K resistors?
>Pulse 2 led is always on .. no out signal
something wrong with R2 (1K) or the jack? cold joint?

>>1299561
>croc clip onto a ground pin?
ground of one of the output jacks?
>led2 always on .. no out signal
follow the voltage, before/after R2 (1K)?

>>1299601
>ground of one of the output jacks?
I guess i can wrap a wire round the ground of the output and attach croc clip to that, there really isn't any room to attach a croc clip anywhere else/

>follow the voltage, before/after R2 (1K)?
Hey I'm fucking clueless which is why I'm asking for help in the hope I can understand this a bit more. I have no idea how to "follow the voltage" please explain

>>1299572

no, never. you need a voltage difference before any current will flow. there's never a difference between a thing and itself.

>>1299608

follow the voltage usually means measure the voltage. if you dont have a voltmeter, then you can use an LED and 1K resistor in series to test for the presence of a positive voltage. LEDs have a polarity, but if you put 2 LEDs back to back, then they'll glow in either direction. the 1K resistor will be common to both.

see http://daily-tips-diy4u.blogspot.ca/2012/03/dc-12-volt-test-pen-for-vehicle.html

>>1299616
>>1299482
>I have a basic digital voltmeter and an old oscilloscope and although I’ve used them both briefly I have no idea how to use either to test a circuit.
So I have a voltmeter but I don't know how to measure the voltage. Your post is telling me that I can follow the voltage if i have a voltmeter, but I've no idea how to do that? Ive only used my voltmeter for basic continuity testing and working out resistor values.

>>1299566
When can you do that?

>>1299620

it's better if you see it rather than read about it. so search youtube for ''measuring voltage with voltmeter''

I work for a company, they make a product that contains lots of universal things, contactors, relays, solenoids, etc.
So I was wondering if the screens we use are similar. Turns out they are, norlake GU140x16j or "GU 7000 series"

I'd like to know if anyone has the patience to give me a basic handwalking through using this display with my own controller. Or does it have a built in controller? How do I control what's on the screen? The norlake website is quite helpful to people who already know what to do, but that's not me.

>>1299649
>Norlake
Noritake
>Handwalking
Handholding

This is the level you're dealing with fyi

>>1299649

grab the datasheet at www.noritake-itron.jp/eng/cs/appnote/gu-7000/apf200_r201et.pdf and see how much you can figure out.

it would take many days of hand-holding to get you up to speed on everything you need to know. fortunately, it seems you can program it using serial (RS-232) so that simplifies the hardware part of it tremendously.

I am working on troubleshooting an analog oscilloscope with a malfunctioning B channel. I think I isolated the issue down to the attenuator board, so I removed it. Would it be a good idea to plug in the A board into where the b board connections are to test this theory?

>>1299674
Never mind. I looked at the oscilloscope, and l looked at the schematic and decided that I should go ahead and do it. And when I did it I got a trace and a response to appear on channel b. So now I know that there is something wrong with the B attenuator. Now I need to look at the attenuator and see what is wrong.

What is the first place that I should start looking for issues? I think that it would be okay to start from the relays, which consist of a reed switch in a coil. What would be the best way test these?

>>1299537
A wall socket is a voltage source; i.e. it remains at constant potential. Ohm's law states that in a circuit the ratio of voltage to current is constant for a particular load, and this property is particular to whichever load you have, and this applies to light bulbs. This property is resistance, R, and the formula is R = V/I. Since R is particular and unchanging for each circuit, and V's RMS average remains the same, the formula I = V/R is much more useful, as it tells us exactly what the current is for a particular resistance and particular voltage; the dependant variable is expressed in terms of the independent variables.

Combine this with our equation for power, P = I*V, and we get P = V^2/R. Rearranging this we get the resistance for a 100W light bulb is 120^2/100 = 144Ω. The only way to get this bulb to light at 1300W is by running it off a much higher voltage, √(1300*144) ≈ 433V.

>>1299724
Relays click when activated, that should be an indicator, but activating them without frying adjacent parts might not be easy. Best bet is to desolder them. Also look for busted capacitors and burn marks on ICs. Not to mention fuses, if there happen to be any.

Is there a commonly-known circuit for creation of a reference voltage equal to the threshold voltage of a FET? I haven't been able to find anything on google.

>>1299746
There are MOSFET drivers, but either way you don't drive them at their threshold voltage, you drive them above it. If you're trying to keep it in the linear region good luck without some negative feedback.

>>1299746
if you're saying you want to measure an individual FET's threshold voltage for whatever reason then pic related will do it. Vth is measured at a given drain current though, typically 1uA-1mA. pic measures at 1mA (1V/1k). it also varies a fair bit with temperature.

you could sort of use this circuit with a dual FET package to create a reference from one FET that will closely match the threshold of the other FET. i have no clue why you would want to do that though.

>>1299428
I prefer an op-amp, personally.

>>1299730
Reed relays barely click. The sound of the rotary switch that directly drives the coils in this application might swamp any sound anyway.

>>1299746
Replace resistor with a decent current source if you need precision.

>>1299775
Good idea. When you trim to 250mV you get the apparent power MOSFET standard of 250µA along with a Vgs of 2..4V.

>>1299786
I want tripfags to leave.

can I put two 8-pin ICs (for example, two 555s) in one 16-pin DIP socket?
I don't see why not since none of the pins are really connected but it doesn't hurt to be safe

>>1299800
yes

I am playing god

>>1299754
I'm fine with implementing it using op-amps.

>>1299775
That's what I came up with, only using it in a common source configuration. I did a DC sweep and found that mine is much more stable with respect to the control voltage. This is for the following FET:
.model NTB52N10 VDMOS(Rg=3 Vto=3.9 Rd=12m Rs=9m Rb=15m Kp=70 Cgdmax=1.5n Cgdmin=.36n Cgs=2.4n Cjo=.75n Is=80p ksubthres=.1 mfg=Onsemi Vds=100 Ron=30m Qg=72n)

I assume Vto is Vth, so this design isn't exactly giving the right answer. I'm going to do a DC sweep on >>1299786 next.

>>1299786
>>1299819
Good stability, but still not on the right voltage, around 300mV too low.

how dangerous is it to substitute similar-value capacitors? I don't have a specific capacitor (.1uf) but I do have a 1uf capacitor. I realize this is a full order of magnitude in difference, but is it gonna fuck shit up?

>>1299826
Depends on the application

>>1299826
It depends entirely what it's being used for. If it's input or output filtering and being tied straight to ground then a larger capacitor is typically never a bad idea, but if it's used for timing definitely not. A circuit diagram helps if you can't discern the issue.

>>1299827
>>1299832
atari punk console like in the OP
more specifically, this diagram is what I'm using.

unfortunately due to the nature of the 555, since it is for timing purposes, it probably will fuck it up

>>1299833
Yep, that'll change your timing. But if you decrease the resistance by a factor of 10 it evens out.

>>1299833
Why not just use a 556?

>>1299872
I have more 555s than I know what to do with

>>>/g/63937189

>>1299800
>can I put two 8-pin ICs (for example, two 555s) in one 16-pin DIP socket?

most likely they wont fit unless you file off some material on the chips. try it on a breadboard first.

>>1299800
>can I put two 8-pin ICs (for example, two 555s) in one 16-pin DIP socket?

most likely they wont fit unless you file/grind/sand some of the material off the ends of the chips, or use an 18-pin socket. try it on a breadboard first.

>>1299800
>two 8-pin ICs .. in one 16-pin DIP socket?

>>1299961
That does work, but you can't put two DIP14s next to one another; you have to leave a 1-pin space in between.

>>1299962
both directions

>>1299974
Pic related: DIP16 width = 19.01mm, DIP14 width = 19.25mm
Note also the half-pins on the 16-pin leadframe ends which are not on the 14-pin leadframe.

>>1299974
>>1299977
Ah, that's strange. I wonder if anyone's stacked a 14 atop a 16 with fine traces to each one?

>>1300007
The dimensions are just less constant than what you expect. For example, I have a 19.9mm long DIP14s, as well as 19.1mm long ones. Generally, if you want to be sure that random DIP packages fit, you have to leave one pin space between. If you want tighter fit, you need to check if it's possible.

>>1300015
Well I've never seen a DIP14 with half-pins on the end and never seen a DIP8 without them, so for now I'll just assume that 8s can be stacked without a gap and 14s cannot. But I usually leave a gap in between for traces anyway since I can't hold my magic marker steady enough to draw traces between component holes before etching.

On a side note, is it a good idea to drill holes before etching? Because 1/8th of my pads don't have copper all around the pin and the joint isn't as strong as it might have been otherwise. I'm just worried that the edges of the holes might etch away a little.

>>1300026
>never seen a DIP8 without them
Now you have seen several. Well, of course it's the size of the plastic molding which matters and only the rightmost chip of these does not obviously fit. And isn't plastic. Occasionally you'll find extra wide plastic ones, though.

Predrilling tends to ruin the resist near the holes, but if you drill first and (carefully) coat after that, the results can be decent.

>>1300038
dat pin 1 mark doe

>>1299643
>it's better if you see it rather than read about it. so search youtube for ''measuring voltage with voltmeter''
Sometimes it’s a bit easier if you have someone who can answer your doubts and questions though. I realise what I’m asking are pretty basic questions, which maybe I should know before even posting here, but isn’t this board for electronic discussions and all that? It seems like a pretty basic circuit so I was hoping it wouldn’t be too much hardship for a helpful anon to maybe walk me through it, so I can understand it and hopefully apply it to a bigger more complicated circuit? We could all just save time and have a sticky at the top of the board that says “just google any question about electronics you may have”

I think I understand how to measure voltage now, but I still don’t really understand what I’m looking for? Without understanding the circuit. It’s kind of hard to know if what I’m doing is right or what I’m supposed to be looking for or even which way round to probe?
>>1299514
Ok so I’m guessing I’m looking from the ic pins 1&9 to the number 2 output?
So as expected the led and the output socket are running at constant 10v which dips to 9.5 while the others go from 10v and dip to 0.

>>1300040
That's quality.

>>1299822
May I ask what is your goal?

Are you going to match MOSFETS, extract parameters to verify the model, or ?

FWIW Vth in data sheets is specified when Vds = Vgs, thus you have to use a current source of some kind and connect gate and drain to replicate test set up / conditions.

>>1300069
So I’m guessing this is the schematic for the second pulse (pic related). So bit 2 on that schematic is coming (left side of schematic) from pins 1&9 on the ic and if I follow that to the output it goes through R2 which is the 1k resistor.
What’s going on along the bottom? Does it just go through the LED and LR2 to ground, what is PJ301b?

>>1300075
As a side note I’ve made a few of these all with exactly the same problem. So I’m wondering now wether it might be something wrong with the main module or the ic.

>>1300073
Oh shit I know that guy! He's the MIT signals and systems guy! I have his book!!! It's the best ever!!!

>>1300084
Yep that's Alan in his youth. ;)

>>1300097
>>1300073
Why though?

Somebody pls help me with this I’m probing about like a madman and have no idea what I’m doing!

>>1300106

post more info and we will try to help.

>>1300108
What else do you need to know?

>>1299482
>>1299514
>>1299561
>>1299601
>>1299608
>>1299616
>>1299620
>>1299643
>>1300069
>>1300075
>>1300077

>>1300111
He's not here to help, he's here to get board famous (assuming he's some other cunt and not that Mr T faggot pretending he doesn't get what the problem is). There is literally no other reason to do it. Ignore all tripfags. They are here for themselves, not you.

>>1300108right now I’m using pic in this post >>1300075 to try and work out what’s going on. All 7 of the outputs seem to be the same circuit: a resister, a led, another resistor and the output jack. So I’m probing from LR2 to the output jack and getting a constant 9.5ish volts and when I do the same from LR1 to output 1 I get a 0-9.5v depending if the gate is being triggered. So gate1 is working correctly and gate 2 seems constant on.

>>1300112
Right ok...would you care to help me out for 5 mins then?

>>1300115

do you have a picture of your scope? it could be a lot of help if it has at least 2 channels that work.

>>1300119
I only have 1 probe for it but it’s a 2 channel scope. This may seem odd but I was buying the scope without knowing if it worked for £50 and the probes were £20 each so didn’t want to buy £40 worth of probe in case the scope didn’t work

>>1300122

that's a pretty nice scope. you have two things plugged in. what is the other "non-probe" thing? you don't have to have a proper probe to put signals into a scope.

>>1300075
>What’s going on along the bottom? Does it just go through the LED and LR2 to ground, what is PJ301b?

Yes, LED2 and LR2 are connected in series, LR2 limits current through the LED, the right terminal of LR2 is connected to ground.

PJ-301B is simply model of the connector, google PJ301B and you'll find plenty of images of that part.

>>1299482
>The two sequencers seem to be acting a little bit differently to each other, one channel on the vca isn’t working at all and one of the 7 pulses isn’t working.

> one of the 7 pulses isn’t working.

Which one? Should we guess or what? Please shed some light on what is not working and why you think it should work. For example on attached schematic to post >>1299482 output OUT7 will be active only if OUT1, OUT2 (and OUT5) OUT3, OUT4 are active. Is that the channel that doesn't "work"?

>>1300124
The other thing is an rca cable with a 3.5mm mono jack I bought for audio

>>1300117
I've been replying to all sorts of junk ITT but analogue is not my jam I'm afraid.

>>1300119
And I do it without the need to make a name for myself you egotistical cunt. Why the fuck do you insist on being a tripfag?

>>1300126
>3.5mm mono jack I bought for audio

if you have the means to attach to that it will work as a probe for the sort of circuit you are debugging.

having 2 channels is essential because you can see the relative behavior.

this guy knows his stuff: >>1300125

I have been following him for a while, here and on other boards. he will be a big asset if he has time to look at your info.

>>1300127
>analogue is not my jam

You can assist with the digital side of his device. Don't be so hard on yourself.

>>1300125
I was about to say from probing about that LR2 seems to be dropping the current down to 2v for the LED and L2 maybe keeping the current to around 10v for the trigger output.

>>1300125
>Which one? Should we guess or what? Please shed some light on what is not working and why you think it should work. For example on attached schematic to post >>1299482 (You) # output OUT7 will be active only if OUT1, OUT2 (and OUT5) OUT3, OUT4 are active. Is that the channel that doesn't "work"?
Sorry I briefly said here >>1299561
>Yep they all light up when attached to the main module and the corresponding steps are lit there. Pulse 2 led is always on regardless, but it didn’t seem to be putting out any signal from the jack.
So pulse 2 is constantly on

>>1300125
>PJ-301B is simply model of the connector, google PJ301B and you'll find plenty of images of that part.
Ah right, I thought this was different to the output, but it’s just the type of output socket. I was thinking it might have been the expansion output from the main module.

>>1300127
NP thanks anyway

>>1300130
>if you have the means to attach to that it will work as a probe for the sort of circuit you are debugging.
Well it will plug straight into the output of all 7 pulses using the PJ301B output jack.

>>1300125
>Please shed some light on what is not working and why you think it should work.
Ok it’s a pulse/trigger generator expansion module for a Turing machine module the first 4 pulses are triggered from the Turing machine from steps 1,2,4 and 7 and the last 3 are the AND pulses they trigger when 1&2, 2&4, and 1&2&4&7 are triggered.
Pulse 2 is always lit which is what I’m trying to figure out why? The ic’s were bought from mouser so I’m guessing they should be of quality. I’ve built a few of these modules and they all have the same problem, so maybe it’s with the ic or even the main Turing machine module itself. Either way I’d still like to troubleshoot this module and work out why pulse 2is always lit as already I feel like I’ve learnt a lot and hopefully if I can work out this simple circuit I can transfer that on to larger circuits for troubleshooting...maybe the Turing machine after this

>>1300137
>Pulse 2 is always lit which is what I’m trying to figure out why?

You can either start tracing the signal form the "beginning" or from the "end" of the circuit.

In essence BIT2 signal comes to unnamed connector (top left corner on your schematic), pin #2. And goes through the circuit to OUT2, then to 4081 and further.

BIT2 is active because it's either asserted by "turing machine" all the time or it's asserted due to some bug in the circuit (like there is an error in somwhere schematic in "turing machine", in PCB layout, damaged/dead component, wire short, etc).

Also you'll likely have to isolate the issue by eliminating everything that is possible to eliminate.

So you first disconnect the module and check output from the "turing machine" Is BIT2 always active?

If it's active then it's likely something is wrong with the module itself.. What can go wrong? For example if BIT2 is asserted somewhere in the module then there should be some connection from +12V to BIT2 (not necessary direct connection or short, there could be like 100 or 1K ohm). How do you trouble shoot that? You start to poke signal path with a DMM and trying to eliminate possibilities. For example remove IC1 or 4081N (is there a socket for it?). Is it still active? If not than it's likely somehow generated by the IC. Then you need to trace all lines that are connected to BIT2 signal and check with multimeter what's going on.

>>1300137
>The ic’s were bought from mouser so I’m guessing they should be of quality.

Yep but keep in mind it's possible to damage ESD sensitive devices and even a genuine part may start to malfunction or even die completely.

>>1300142
Hey thanks for taking the time out to reply.
It seems like I’m in way over my head here on this one. I was thinking maybe it would be a bit more of a simple case of checking the 4 components (led,2 resistors,and output) against the signal coming from the ic. I’m guessing I’ve already established that the ic is sending a constant pulse to output 2 if my readings are correct.
So now I’d need to trace it back through the Turing machine from the pulse 2 pin on the connector from the main module. I think this might be way too much for me unless it’s something glaringly obvious.
If the problem is in fact coming from the Turing machine module. It should be putting out a constant voltage at the output connector to the expansion module right? In the schematic (pic related) I can see the pin out for that connector. So would it be possible to do a quick test from there just to confirm the error is coming from the Turing machine?
I’m guessing someone with a bit of experience and who is confident in reading a schematic could look at that and say right if I put a volt meter from this point to this point you should get a certain voltage (zero?) when there is no step and (10v) when the step is on?

I have some super cheap TEC1-12706 units (pic) I want to use as TEGs. I've been playing around and generating energy from them is pretty easy, just not useful at the low temp testing I've been doing. However, their max working temperature is only 80C/176F. The heat source I'll be using can reach a max 593C/1,100F. The heat will travel through a 1/8" thick copper plate, to the TEC units, through the TEC units out the other side through a large aluminum heat sink. The system is intended to be fanless. The TECs will be on both sides of the copper plate, thus pulling heat at a faster rate, so to remain cooler per TEC unit.

How can I make sure the heat doesn't cook the TEC units? It appears they are sealed with white silicone caulking. I know the heat reaching the TEC units can be pretty high, so long as the heatsink is able to keep the TECs cool enough. Thus, simply having the copper plate be 80C where it meets the TECs will be too cool when the TECs are attached.

I've been thinking about getting an IR thermometer gun (brand name recommendation?) to find out the temp of the copper plate (during low temp testing) then the temp of the aluminum heat sinks, so I can know the temperature difference. I'll take a few readings at different temp input so I can hopefully get a better gradient understanding. Then I'd be able to calculate/estimate how much heat will be affecting the TECs at the higher temp inputs of normal running. I'm not exactly made of money and frying a few TEC units is something I'd like to prevent during the design and testing phase.

Does that seem like a good way to test, calculate, and estimate this?

>>1300236
thermal pumps in general aren't really designed to handle such extreme temperatures

>>1300238
There must be some misunderstanding. It won't be exposed to extreme temperatures. I just need to know if the aforementioned thermal testing procedures would be a good way of discovering the "flow rate" of heat reaching the TECs or not.

Theoretical Examples:

Small heat sink
Test 1: 26.4C Plate temp. 22C Heat Sink temp. Difference of 20%.
Test 2: 60C Plate temp. 50C Heat Sink temp. Difference of 20%.
Test 3: 96C Plate temp. 80C Heat sink temp. Difference of 20%.
>Theoretical Max: 96C Plate temp. 80C Heat sink temp. Difference of 20%.

Large heat sink
Test 1: 26.4C Plate temp. 20C Heat Sink temp. Difference of 24.25%.
Test 2: 60C Plate temp. 45.45C Heat Sink temp. Difference of 24.25%.
Test 3: 96C Plate temp. 72.72C Heat sink temp. Difference of 24.25%.
>Theoretical Max: 99.4C Plate temp. 80C Heat sink temp. Difference of 24.25%.

Fan+large heat sink
Test 1: 26.4C Plate temp. 15C Heat Sink temp. Difference of 56.81%.
Test 2: 60C Plate temp. 34.09C Heat Sink temp. Difference of 56.81%.
Test 3: 96C Plate temp. 54.54C Heat sink temp. Difference of 56.81%.
>Theoretical Max:125.44C Plate temp. 80C Heat sink temp. Difference of 56.81%.

Obviously, none of this is correct. I'm sure there's a gradient and I really need to know what the the ceramic TEC plate attached to the copper plate temperature is. Once I figure out what the max temp of the copper plate needs to be in order to maintain 80C or less in the TEC unit I can then adjust the copper plate to ensure the max temp of 593C/1,100F never makes the TEC unit go above 80C. I'd do that by adding some heat sinks along the copper plate between its max hot end and the TEC end to pull heat out of the copper plate before it reaches the TECs..

>>1300249
if you have solidworks it's incredibly simple to set up a thermal simulation even including convection. you can use a surface heat flux to simulate the peltiers.

>>1300251
also if you can explain your application regarding the nature of the heat source, the number of peltiers, and rough dimensions of the heatsink, i can walk you through some thermal calculations. i can't give you ballpark figures without knowing what your source is.

>>1300251
>>1300257
Thanks, but no. I gave up CAD a long time ago in favor of pencil & paper and hands on work. It has been far more rewarding that way.

>>1299920
anyone?

quick (and very stupid) question, i want to use a small incandescent bulb from a string of Christmas lights but i don't have any sort of min or max current ratings.
should i just determine this experimentally (i have a handful)? or is there a standard value or way i can determine it without blowing it

>>1300354
buy a variable voltage power supply. cheap is fine. switching is fine. everything listed below is optional so don't drop a bunch of cash until you know electronics is your hobby.

>hot air gun
skip it for now because you likely won't be interested in fine pitch SMD for a while and you can do heatshrink with a lighter.
>iron
i wouldn't buy an iron under $50, you'll use it too much to make chink shit worth the hassle.
>pogo pins
i've never felt i needed pogo pins, those are more for making test boards for production.

i'd get bulk ebay packs of:
>chinese arduino nanos
>esp8266
>m-f, m-m, and f-f jumpers
>assorted LEDs
>500pc+ resistors, as large a quantity as you can get
>100pc+ capacitors, ceramic + electrolytic and also films if you can
>10pc+ a few toroidal inductors, 3A+, whatever inductance
>50pc+ axial inductors
>50pc+ trim potentiometers
>regular potentiometers
>assorted zener diodes
>assorted diodes, power+signal (1n4007, 1n4148, some schottkies)
>assorted bjts, npn+pnp (2n3904/06 and some higher voltage ones)
>power bjts (tip36/35)
>power mosfets (infineon series TO-220s, get high voltage ones and high current ones)
>pushbuttons
>cheap ass stepper motors
>DIP switches
>phototransistors
>photoresistors
>jfets
>small signal mosfets (2n7000)

you can buy stupid electronics bullshit all day. tally up the prices for those things and if you don't like the numbers take a few things out. you'll also want 555 timers, some 4000 or 7400 series logic chips, PWM chips, op amps, comparators, etc.

>>1300367
>i don't have any sort of min or max current ratings
incandescent lamps are usually rated for volts applied
for a christmas tree series string lamp start with about three volts

>>1300130
>this guy knows his stuff: >>1300125 #
>I have been following him for a while, here and on other boards. he will be a big asset if he has time to look at your info.

And this shit is EXACTLY why we hate tripfags. This is not fucking social media, we do not vouch for each other, we do not promote each other, we do not follow/like/share, we post. If your info is good we listen and respond, if not it gets buried. And now you're fucking samefagging under a different trip to promote yourself? Absolute cancer old man.

We are an anonymous image board. Learn how that works or expect to get called out over and over. We actually had a good drama free thread, then you came back. Please fuck back off to wherever you went sooner rather than later.

>>1300152
>>1300137
>>1300134
>>1300126
>>1300122
You can fuck right off as well for enabling this shit. If you dont understand this fundamental of anonymous image boards, you have no place here either. Be patient and wait for someone who is capable of posting advice without the need to garner e-fame in the process. The other guy is right. He's not here to help you, he's here to help himself.

>>1300394
>>1300125
>>1300130
i just realized there's "two" of them now. here we go.

>>1300396
No, theres not. Its mr cunt samefagging for himself. If he wasn't new here, he'd know how easy it is to spot. Aside from zero post history from his alter ego, fucked if I'm gunna point out how we know.

>>1300378
oh, that's very curious. i'll have to do some reading. many thanks!

>>1300371
>i've never felt i needed pogo pins, those are more for making test boards for production.
actually, I do have some devices that I want to modify, which is why I mention some odd materials:
https://wiki.hackerspace.pl/projects:zsun-wifi-card-reader#ethernet_port

thanks a LOT for the list.
btw, shouldn't these lists of materials be left somewhere in the OP?

>>1300405
>in the OP
there's a 2000 character limit. where would you have them?

>>1300408
we could put it in a pastebin. others can expand on the IC list, since i sort of threw that in when i got tired of typing.

>>1300408
this >>1300409 , obviously you wouldn't leave a big ass list in the op, but a link to them

>>1300367

if you have the original x-mas lites, then it's very easy to determine the voltage of each bulb: assuming you have 120V power, you just divide 120 by the number of lites. e.g. 30 lites = 4V each.

>>1300394
>The other guy is right. He's not here to help you, he's here to help himself
In all fairness he’s the only person here that’s taken the time out to help at all.

>>1300450

of course, coz anonymity is just the excuse many posters need to act like obnoxious assholes.

>>1300451
Hey I’m not trying to start some shit was just hoping to learn something. Guess I’ve come to the wrong place.

>>1300455

dude, i was agreeing with you. geez!

>>1300457
Sorry I was reply to you but not at you

not sure if you two should keep it up
or get a room at rebbit

>>1300465
>Sorry I was reply to you but not at you

that's a weird phrase; sounds like it was translated from french. you're french?

>>1300470
I meant I was replying to you not at you.

No I’m not French I’m British. Does nationality help get advice in here? I can be French if you like?

>>1300473
>I can be French if you like?

no, it's ok. bad teeth is preferable to body odour.

>>1300399
So I'm not the only one who noticed the IP count stayed static through that little clusterfuck?

>>1299514
We were less than 100 posts into a 350 post thread, on one of the slower boards of 4chan. You have admitted many times you are in over your head, because you have chosen to shortcut your way up to a major project instead of learning the basic building blocks on the way like most of us have. You are trying to fly an aircraft when you barely know how to drive.

If you're too impatient to wait, that's not our problem, and we are obligated to explain things to you that are 5 notches above your current knowledge level, but I'm not surprised that you're being attacked considering a majority of the thread has this guy filtered for being the sort of faggot who will do shit like assuming a second trip to back his first trip. I don't give a fuck if the guy is Walter H.Schottky himself, you don't go wading into a community that was ticking along perfectly and completely ignore the sometimes polite but often raging requests to abide by the standards of the community. If you choose to engage that person, then you may as well put a trip on so we can filter you as well.

>>1300455
> Guess I’ve come to the wrong place.
You may be right.

Sage because, once a-fucking-gain, tripfag drama ruining /ohm/

>>1300476
I don't even know how I quoted >>1299514, I meant to quote >>1300450.

to think the last 15 worthless posts wouldn't have been here if only one person would stop trying to attention whore on an anonymous forum

>>1300476
>Sage because, once a-fucking-gain, tripfag drama ruining /ohm/

this post is like someone going around smashing all the windows, then complaining about a draft.

>>1300480
> I have a virus that is causing damage an existing colony of bacteria in my body.
> rather than eliminate the virus, I'll just kill the colony.

That's how retarded you sound.

>>1300480
>someone does something obnoxious
>multiple people react
>guys stop shitting up the thread!
tripfags absolutely kill little generals like this. since you can't reasonably control anonymous, the only single individual that can end this drama is the tripfag. so the onus is on him. he doesn't even need to stop posting to do it, he just needs to remove his trip. if he cares at all about this thread's quality and not just his forum rep he'll do it.

>>1300484
>>1300483
These. The onus is on the disruptor to stop, not on the disrupted to tolerate the disruption. And despite all this that faggot is still tripping. What kind of arrogant cunt continues despite all this bullshit? A bullheaded old man who thinks he's better than the "boring" anons he posts beside, that's who. It's fucking bullshit.

>>1300476
My bad I honestly didn’t realise I was that far in over my head to start with. I thought the problem was with the pulse module so as you can see that’s a pretty simple module on its own. So again I thought this would be a good place to start with it only having 4 components per part. I also assumed from previous visits to ohm that it was a bit more friendly in here and have never seen such hostility towards someone just conversing with a tripfag?
I will sit patiently and maybe someone will feel like helping me out.

>>1300494
>more friendly in here and have never seen such hostility towards someone just conversing with a tripfag?

Thats because we have never had tripfags ITT before. They are reacting to him, and those who don't understand how much better /diy/ is without them, like you.

/diy/ doesn't do tripfags, period. Go look at /g/ to understand why.

>>1300484
>the only single individual that can end this drama is the tripfag.

well, either him or those who lack the most basic self-control to ignore the trivialities of life.

>>1300503
i completely get where you're coming from but it's a simple truth that you can't get 3+ anonymous people to agree to do anything. so if your end goal is for the thread to go back to normal, the only practical solution is just for the guy to drop his trip. frankly after all this the fact that he still hasn't done so shows he's maliciously stubborn anyway and is probably reading these posts and stroking his dick.

>>1300499
>Thats because we have never had tripfags ITT before. They are reacting to him, and those who don't understand how much better /diy/ is without them, like you.
It’s funny last week I was threatened with a ban on the board I frequent the most for being hostile towards a tripfag there. I was told that abusing the tripfag just shits up the thread and has nothing to do with the topic of the board.


/diy/ doesn't do tripfags, period. Go look at /g/ to understand why.
No you’re ok I’ll take you’re word for it.

>>1300505
>the only practical solution is just for the guy to drop his trip.

not, it's not the ONLY practical solution; i just now gave you an equally good one: ignore the trivial, stop acting like conformist zealots. aka, self-control. aka, acting like a grownup.

>>1300513
are you saying it is practical to get anonymous people to do what you say? i don't know how anyone could possibly think that. i've been in generals on this site since they first started becoming a problem and i've literally never seen that happen. i've seen lots of generals die from attention whoring though.

>>1300516

it's better to guide the children than let chaos win.

>>1300521
your ideals have blinded you

>>1300522

living is easy with eyes closed - J. lennon

>all this about one meaningless tripfag

>>1300528
In complete darkness we are all the same, it is only our knowledge and wisdom that separates us, don't let your eyes deceive you
J.Jackson

>>1300549
some people just think too much of themselves to hide their light under a bushel

>>1299048
How to clean soldering tip, that is black and bad, due to shitty solder and overheat to melt it.

>>1300553
when mine became unusable i went over it lightly with a dremel. it didn't help a lot but it was good enough to last me until i replaced it. i believe most tips are copper with an iron plating so you need to be careful not to remove so much that you expose the copper.

>>1300556
Yep, those tips are made of copper with some sort of nickel plating, or cheap generic tips are made from steel and plating.
But the problem is that my soldering iron is generic 10$ 30W, and it is impossible to find tips for it.
And it works surprisingly well, just as well, as CXG 936D soldering iron with thermal feedback with Hakko 900 tips.
Also I want new iron... Is it worth buying jap soldering iron from Goot or Hakko for 20$, or it is better to buy Chinese CXG 936D with temperature gimmick?

>>1300564
i'm starting to get annoyed by my weller which i imagine is better than chinese shit. i'm getting myself a temp controlled hakko for christmas and i'd advise anyone that isn't a poor student to do the same. the ones my college lab had were wonderful.

>>1300571
Yep, chinese shit is shit.
I used CXG 936D only because I could install original Hakko tips, that const nearly as much, as soldering iron.
Build quality - not-soldered properly power wire, that caused blackout, wabbly everything... That is why I sold it.
10$ shit is better at it, nothing is wabbling around. But not enough POWAH.

So, I guess, I should buy normal iron, with nicrome heater, but normal. Or even hakko station...

>>1300553
The brass brush tool, whether dremel or manual, is ideal for this.
At least use a sponge or something to keep the tip clean and be sure to put some tin on it before you shut it down. The wad-of-brass-turnings tip cleaners are pretty awesome.

>>1300564
>hakko for $20
orly.jpg
Two nice things about stations:
>you have a place to put your iron down
>they are easier to open up and inspect for wabbly shit
Some clone stations aren't bad, but as in all things chinese, you get what you pay for.

Hey guys. I'm getting supplies ready to make what is essentially a matrix mixer with momentary buttons (with a switch for each button to oggle between NO/NC functionality) instead of pots. Just Imagine pic related but with buttons instead of pots. The idea is to be able to abruptly switch on and off different input signals going to multiple outputs.

There's two main concerns I have:
1) I want to eliminate ground hum/noise as much as possible, and I don't want to use shielded cables for each connection because that would take way too much time. Should I get a metal chassis then tie all grounds to chassis?

2) I did a test circuit with two inputs and two outputs. The outputs acted as left and right channels, with each input being a different source. I was able to successfully hard-pan a single input in any way I chose, but if both outputs for one inout were initialized then the other input was introduced, no matter what output this second input was sent to, it would sound as if it were a mono signal.
So for example, let's say I have drums (in1) going to both outputs (left and right channels). I then press the button for keyboard (in2) to go to the left channel: instead of (in2) showing up in the left channel, it shows up in both. The second I release one of either of the two buttons controlling which out (in1) goes to, the effect stops and (in2) is in the left channel only as intended.
How do I make it so that this wont happen?

>>1300590
>How do I make it so that this wont happen?
use an active mixer

>>1300584
>The brass brush tool, whether dremel or manual, is ideal for this.
Okay, I will try it.
>At least use a sponge or something to keep the tip clean
I use toilet paper, dry. Kinda werks and everyone looks on me like on an idiot.
> and be sure to put some tin on it before you shut it down.
I do, but this time I had very dodgy solder.
>The wad-of-brass-turnings tip cleaners are pretty awesome.
Never used them, because they were to expensive.
>orly.jpg
Yes, for nicrome heated 30W. The red series. Or Goot...
Not stations, of course. Stations will cost 200$ at least.
>Some clone stations aren't bad, but as in all things chinese, you get what you pay for.
It is lottery of some sort, because in one retarded chinese screwed transformer well, in other it was floating in case and damaged simplest op-amp thyristor-based controller of temperature.
I am tired of it. Because all friends and coworkers received normally assembled irons with thermal control, hot-air soldering station... But I end up all times receiving wabbly shit.

Actually, I do not really need a station with temperature control, I'm fine with picrelated...
The only feature I need from stations - some sort of magnetic or shake switch, that makes iron to slightly lose the temperature.

>>1300600
>The only feature I need from stations - some sort of magnetic or shake switch, that makes iron to slightly lose the temperature.

I made one of these years ago by attaching a cage style soldering iron holder to a shallow metal box.
The iron holder was allowed to pivot slightly on a hinge at the back.
The front edge of the holder base pressed on a microswitch inside the shallow metal box.
(just like in your schematic)
When the iron was in the holder the switch was OPEN
When I picked up the iron the switch CLOSED applying full power.

>>1300595
Can I run it off a 9v (wall preferred, battery ok) if I have four inputs? As I understand it, there needs to be at least one or two op-amps per input; if I can't run them all off of 9v it's nearly worthless for my needs.

>not using a temperature controlled iron

>>1300600
>toilet paper
No wonder your tip is shot.
A wet kitchen sponge will work much better.
>stations
Aoyue seems to be among the better clones. I got an 888 2-in-1 station for $80 and it's everything I could ask for.

>>1300614
Sure, easy. Audio op-amps rarely consume more than 5mA per channel.
You really only need one per output. An input buffer for each channel is a good idea, but not strictly necessary if 180° phase shift isn't a problem for you. You can run them all off the same rails no problem. The RC4558/RC4136 is a common choice for audio, as is the lower-power TL08[124]. 9V is pushing the minimum recommended supply voltage on both of these, so circuits may not work optimally with a nearly flat battery.
If low voltage operation is important to you, the LM324/LM358 are available, but their distortion figures are somewhat higher.

I had this little expansion boards made (pic related) for a pam8403 module. It works very, very well, except the amp distorts like a bitch at higher volume. I'm going to install it in a small speaker and I don't want to waste the potentiometer. Can I just put in a resistor instead of the pot? The resistor would be of whatever value the pot is once the it's set to not distort.

>>1300651
yes. you may need two resistors if it's not wired as a rheostat but most likely it is.

>>1300653
Thank you, kind sir.

>>1300653

you need to create a voltage divider, so 2 resistors is the usual way to do it. to get away with just 1 resistor, you'd put it in series with the input thus using the input impedance of the circuit as the 2nd resistor. the first method is usu. less noisy coz the resistors are gonna be smaller.

>>1300130
>this guy knows his stuff: >>1300125
>I have been following him for a while, here and on other boards. he will be a big asset if he has time to look at your info
Seriously.. What the actual fuck. How far up your own arse do you have to be to even consider samefagging for yourself under another trip? This is an image board, not twitter you cunt. We don't follow shit, we judge things on merit, and once again, you have demonstrated how far removed you are from everything 4chan stands for. Fucking leave.

>>1300491
>old man
And fucking how. I am literally a dad full of terrible dad jokes, and I would expect, nay, demand, to be gut knifed if I made a "joke" like pic related.

Once again it's become a clusterfuck because of one special snowflake, I'm abandoning /ohm/ till this faggot crawls back off to which ever social platform he came from. And for fucks sake, will someone put something about tripfags needing not apply in the next OP..

>>1300723
It’s a funny thing to come into a thread asking for help and then being told to fuck off because the only person willing to help you 24 hours after your original post was a tripfag.
It’s now 48 hours since my first post and this thread has 34 posters so far and still nothing other than anons discussing how tripfagging ruins this board. Now like another anon has clearly pointed out to me, no one here is obliged to help me and I understand that, but isn’t that the whole point of this board?
Just a suggestion from a (mostly) outsider opinion. Why not just block/ignore all posts from the offending tripfag that gets everyone’s knickers in a twist and go about your business here...whatever the fuck that is?

>>1300723
>And for fucks sake, will someone put something about tripfags needing not apply in the next OP..
upboat

>>1300729
> but isn’t that the whole point of this board?
The board is called "Do It Yourself". Make of that what you will.

> Why not just block/ignore all posts from the offending tripfag
The problem with ignorance is it sets no precedence. Back when /diy/ first launched we had a shitload of tripfags come over from /g/ who tried to claim it as some sort of sovereign state. It got to a point where ignorance no longer worked, anons rallied, and mods began banning them because of all the shitposting they were doing for the sake of shitposting. We like having no trips, we value information over identity, and by forcing an identity on an anonymous board, you demonstrate your determination to be a board celebrity, not a contributor to solid information who gets a kick out of knowing you have helped someone for no other reason than a genuine desire to help someone.

Mr T is by no means a shitposter, but he is displaying an ignorance of the norms of the board. On any other forum, if someone comes in shitting on the norms and culture of the joint, they get their shit handed to them by mods. As we all know (and especially since gook moot took the reigns) moderation is next to dead now. So it becomes the job of anons to self moderate, which is what you are seeing. Filtering is fine, as time has progressed it has been obvious that more and more anons are doing it as replies to his post have dwindled more and more, but for the same reasons shadowbans rarely work, a strong message is better.

I'm sorry you're getting ignored, but this thread has basically gone to shit anyway. The last one was a lot better, again, because Mr T was nowhere to be seen.

/2c

>>1300743
>The board is called "Do It Yourself". Make of that what you will.
Ok but this thread is sub named /ohm/ and is a constant fixture here (I have been lurking here a while) so Am I to presume this thread is purely for showing off electronic projects you’ve diyed? I guess that would make sense although doesn’t seem very fitting of the board culture I’m used to here. When anons come into my home board asking for advice I’m keen to help them out regardless of their knowledge, we also have name and tripfags which we generally ignore. Maybe I caught this thread on a bad day as I’ve been here many times before and have always had solid advice.
Like I’ve already said the circuit I’m building seems like a beginner circuit to me and would be comparable to examples given in introduction to electronic books.
I’m just trying to learn and after buying a scope thought I’d post here for advice. I guess I’ll go learn myself and come back here when I’m fully qualified to shit the thread up with unrelated content regarding the age old debate on using names on an anonymous board.
Thanks guys.

>>1300743
>moot took the reigns)

lol. reins.

a king reigns. a horse rider holds the reins.

>>1300553

thermaltronics makes an affordable product called "tip tinner". here's a quick vid of it being used: https://www.youtube.com/watch?v=WFaOPb017FM

>>1300590
>>1300590
>1) I want to eliminate ground hum/noise as much as possible, and I don't want to use shielded cables for each connection because that would take way too much time. Should I get a metal chassis then tie all grounds to chassis?
That would help. Other options are using differential signalling and twisted-pair, or increase signal level so you'll get higher signal/noise ratio. Lowering input impedance may also help (a circuit with let's say 1Meg impedance is more sensitive to electrostatic interference then a circuit with 600 Ohm.

>>1300590
>How do I make it so that this wont happen?
Simple mixer built with just few switches is a bidirectional device as sending one signal to 2 channels will effectively short these 2 channels together. Makes sense?

How to prevent that: introduce signal buffers ( https://en.wikipedia.org/wiki/Operational_amplifier_applications#Voltage_follower_%28unity_buffer_amplifier%29 ), and sum outputs properly, e.g. like https://en.wikipedia.org/wiki/Operational_amplifier_applications#Summing_amplifier - you can omit the op amp and connect right terminal of Rf to ground, and get summed signals from Rf left terminal.

>>1300553
>How to clean soldering tip, that is black and bad, due to shitty solder and overheat to melt it.

DIY way
If the tip is completely fucked up:
1. turn the iron off and let it cool, scrape the tip with a knife to remove oxides and junk.
2. turn the iron on and immediately apply your favourite flux (rosin, rma223, whatever) and start poking the tip with a solder wire or rub the tip against solder wick with tons of solder and flux.
3. If you are unlucky you have to repeat steps 1 & 2 and use different (more active) flux. Like phosphoric acid or aspirin (warning: good ventilation is required).

>>1300152
>If the problem is in fact coming from the Turing machine module. It should be putting out a constant voltage at the output connector to the expansion module right?

Right.>>1300152
>In the schematic (pic related) I can see the pin out for that connector. So would it be possible to do a quick test from there just to confirm the error is coming from the Turing machine?

Yep

>>1300152
>I put a volt meter from this point to this point you should get a certain voltage (zero?) when there is no step and (10v) when the step is on?

Yes, you keep one probe connected to ground and inspect pins/terminals/wires with another probe. It's really simple.

>>1300236
>Does that seem like a good way to test, calculate, and estimate this?

It depends on accuracy desired. IR thermometer isn't the best tool for the job, you need either thermal camera or use few thermocouples attached to key points. Mechanical mods are often required for thermocouple installation.

Gays! Why are you keeping derailing threads instead of well be on topic and share technical knowledge? How hard can it be to stay on topic?

http://www.autismeducates.com/2016/07/05/top-5-ways-help-child-stay-topic/

>>1300795
>>1300779
>>1300774
>>1300767
Why are you posting with a trip?

>>1300796

if it pisses you off, that's a good enough reason.
cry more, bitch.

>>1300795
>How hard can it be to stay on topic?
How hard can it be to post without a trip shitlord? You gunna bring mr bill out for a free upvote again?

>>1299730
>>1299785
This is the size of the reed relays that I am dealing with. I decided to test them using a weak magnet and the continuity setting on my multi-meter and made sure that they would activate if the magnet was in proximity.

What would be the best way to test the coils to make sure that they are fine? I tried looking for the two ends of the little wire making it up to test continuity, but when put my multi-meter leads up to the ends where the wire is attached to it doesn't go off. My guess is that my meter might not be sensitive enough. What would be the best way to test the coils? I'm thinking that I could use a bench top power supply to see if I apply power to them if the reed switches actuate.

>>1300820
Pic of some of the coils in question.

>>1300824
Detail. If you look closely the wire is attached to the two bottom posts.

>>1300820

dont use the continuity setting. use the ohm's scale, say 20K. you'll probably read around 500 ohms if the coil is good.

alternately, apply whatever voltage is required to the coils and test continuity of the reed switch. this tests the whole system.

>>1300633
>No wonder your tip is shot.
Ok. I will try special metallic mesh
>A wet kitchen sponge will work much better.
No, sponge melts and makes everything worse.
Wet toilet paper kinda forces tip to oxidize. Only glycerin kinda worked.

>>1300765
Didn't know about this thing. Thanks.
>>1300774
Acids are bad, I actually damaged one tip, when I was tinning headphone wire with aspirin. And this stuff is aweful.

Can this circuit be used for proportional base drive of a power transistor?
How should it be modified to use "normal" parts, such as LM358 op-amps and (preferably) N-channel FET?

>>1300908
>not owning and using equal numbers of P-fets

>>1300834
Bought gas plumbing 50/50 solder... Tinned perfectly.

So, do not buy shitty solder.

>>1300921
>50/50
50/50 what?

>>1300923
50 lead 50 tin

>>1300908
That circuit would be a total overkill for driving BJT bases. What are you actually trying to do?
That said, you can build a differential amplifier with G=5 from LM358 and assuming your opamps run from higher supply than the fet, you can invert the circuit logic to drive n-fets.

Ok, delayed response due to job/holidays:

First, thank you >>1300633 .

Next, I want to ask >>1300767 :

So with twisted pairs, do both conductors in a pair do to the same source? Like if I connected one solder lug of a switch to another, for example, would it simply be a matter to twisting two wires together, soldering them together at both ends then that pair basically acts as one wire to bridge between the lugs?

Also, I'm woefully ignorant of impedance in general. From what I'm reading, there isimply needs to be a resistor parallel to ground... but from where? Or is this something that requires another buffer/op amp(s)?

I want to make a plug socket (uk), does anyone know where I can find a list of the specs/dimensions I need to keep to?

>>1301010
On each end, one conductor goes to the source, the other to ground. The objective is that any EMI/RFI that encounters the pair induces the same current in the same direction along the wires, and so cancels itself out.

>>1300908
LM358s don't reach the + rail very well. If you only have N-FETs, there's two reasons to try to flip the circuit and whatever it's driving to the low side.

>>1301031
IEC 60050, BS 1363.

>>1301037
>IEC 60050
absolutely disgusting get that filth outa here

>BS 1363.
thats the ticket lad, the clue is in the name. literally you should refer to these as bs1363 plugs and sockets if you want people to know what you are talking about, otherwise you might end up with some smart arse putting in BS546 for a joke, or maybe iec60309 or god forbid maybe even some of that nema shite when you ask for a socket.

>>1300908
common mode range includes ground

>>1301034
Okay, so it's basically the same as using shielded cables. My question is, is tying all grounds to a metal chassis going to be enough, or should I ALSO use shielded/twisted cables?

>>1301087
Basically similar, but slightly less effective than shielded whose braided full coverage intends to keep the signal off the signal lead vs. TP which intends to balance.
The metal box, if grounded, ought to sufficiently shield against hum and noise from outside. Crosstalk between channels might be evident if you just use single wires and don't dress them carefully, apart from each other. Fortunately, it's easily redressed should it prove necessary.
>tying all grounds
Tying them together should be fine. If you do get noise from a particular device, you might want to read some of the extensive literature on ground loops and their mitigation.

HERE WE GO AGAIN BOI

>>1301094
forgot the pic

also roll

any possible issues with using a triac to switch an smps? a monitor in particular. can't think of any.

>>1301107
the only concern I can possibly think of is inrush current surge, which may or may not be moderated sufficiently by the soft-start circuitry internal to the monitor. when in doubt, blow it out ig

Can someone explain why the minimum voltage rating for the last caps is 706V even tho the output is way over 2kV?

>>1301145
dumb, lazy way of explaining it but suppose you have ten 9V batteries in series. the total voltage is 90V, but each individual battery obviously still only has 9 volts across its own terminals. the same concept applies here with the capacitors.

>>1301146
The source also explained it somewhat like that. Hard to wrap my head around how the end of a 1kv can spit out a 10kv arc

I want to make my own function generator using a microprocessor. I don't want to just copy some design from the internet, though (I already did that for a frequency counter that I built).
I'm thinking that the microprocessor would only be capable of generating a square wave with an adjustable frequency, then I would need to build additional circuitry to make a sine wave and triangle wave. Then if I'm feeling really adventurous, I could add some boost circuit to have a greater output voltage range.

Beyond what I just described, though, I don't really know what I'm doing. How would I go about choosing a suitable microprocessor for this? I was thinking of using a PIC because I own the in-circuit debugger for one and that's what I used for building a frequency counter, but have no idea which model to buy.

>>1300723
He deserves all the thanks he can get. I mean, I wouldn't be where I am today if it weren't for upstanding netizens like Mr.T - Kun

>>1301161
First place to start would be defining what kind of range of signals you want to produce, with what kind of accuracy/resolution.

If you only care about square waves, what you're looking for is a microcontroller with fast timer hardware. A typical PIC is probably fine up toward the 100kHz range depending on how much precision/resolution you want.

For triangle/sine wave output, converting from a square wave is only really practical if you're looking for a relatively narrow frequency range, if you're looking for a wide frequency range the usual approach is Direct Digital Synthesis, where you run an analogue to digital converter directly from your calculated waveforms. There are a few different ways you can do this, you can buy a chip like an AD9833 which have the control chip, sine wave generator ROM and digital to analogue converter all in one chip, all your micro does is talk to it over a SPI interface to set up what frequency/waveform you want. Or you can use a microcontroller, FPGA or CPLD to run your own digital control feeding an ADC either in the micro or external.

>>1301171
>AD9833 which have the control chip, sine wave generator ROM and digital to analogue converter all in one chip, all your micro does is talk to it over a SPI interface to set up what frequency/waveform you want.
Nice, nice, this definitively sounds like something I would want to do. Thanks, I'll look into this.

>>1301166
Hello probable same fag.

>>1301150
capacitors divide ac potential much like resistors divide dc potential. worth noting that cap tolerance is typically wider than resistor tolerance so derate appropriately.

>>1301191
ten burgerbux though

>>1301228
it's cheaper in bulk or from china, can get a dev board with the chip + reference crystal on an easy 0.1" header for just over 3 clap coins on ali https://www.aliexpress.com/item/AD9833-Programmable-Microprocessors-Serial-Interface-Module-Sine-Square-Wave-DDS-Signal-Generator-Module-GY-9833/32837306889.html

>>1301228
The capacitor tolerances don't matter. It's basically a series of rectifiers and all the capacitors are charged to the same voltage, if the output is unloaded. If it's loaded, they charge to some lesser voltage.

>ten burgerbux
It's quite reasonable for the performance. If you're happy with much lower frequency range, you can emulate the digital part of the chip with your MCU and use it to drive a suitable DAC. Or a PWM, if you're destitute.

hello, how do these devices work? is it simply a voltage reading? or is it more complicated than that?

does it need to be connected in series or parallel to the load, thanks

https://www.amazon.com/12V-Lead-Acid-Battery-Tester/dp/B01M4J6FJ4/ref=sr_1_4?s=industrial&ie=UTF8&qid=1514033785&sr=1-4&keywords=12v+battery+indicator

>>1301264
>is it simply a voltage reading?
At that price and size, yes.
Volt meters are connected in parallel.

>>1301273

thanks man, i figured as much, im planning a small project (my first real project) its a really simple switch panel to control flow from a battery that will be in my backpack to go to the night vision goggles on my head, and another switch to illuminate an IR light if i need it, as well as a battery indicator that can be turned on/off (for total darkness)

should be simple enough. honestly. will keep you nibbas updated

>>1301276
Cool project stalker anon

>>1301276
>hauling around a lead-acid battery on your back while stalking
enjoy your workout, hope you don't get chased by the cops

>>1301288

>hauling around

because small 7AH alarm batteries are so heavy?

>>1301290
>only six pounds
carry on then

>>1301145

I'm trying to repair a small fridge I found, the starting relay is bad, there is no shorts in the compressor.

So I found this off an old fridge, already tested it out with my fridge which is 120v. The relay/overload says 220v so I'm guessing it won't work with 120v right? Tbh I already tested it, doesn't turn on, but figured I would ask you guys. Last time I was trying to get it too work, I believe the light turned on in the fridge

>>1301447
That's a capacitor, not a relay. Are you trying to use that part to replace one in a different fridge? If so, make sure the actual capacitor value (15 uF for the one in your image) on the part you're replacing matches the new part.

That is because Vpp=250V*2sqrt(2)=707V

>>1301449
>That is because Vpp=250V*2sqrt(2)=707V

noted for future reference.

>>1301447
That's a run capacitor the refrigerator uses to lower electrical consumption of the compressor. that looks like it is good for a 1/4 hp thru 1 hp compressor. if you want to check and see if the compressor is good, put current (115v) to the common post (c)and the run post (r) and then short the start post (s) to the run, only momentarily. if the compressor starts its good, if not chuck it. ( c on top, r on right, s on left)

>>1301489
>a run capacitor the refrigerator uses to lower electrical consumption of the compressor.
Run capacitors are used to offset the phase of one coil for a 2-phase induction motor, its impedance making that set of motor coils take less current is not an intended function of the capacitor, but I imagine the number of turns on those coils are adjusted for this. Larger single-phase induction motors often have a start capacitor which turns off after a short while because it makes the motor less efficient, while the motor continues to run on a single set of coils.

Does anyone have an opinion on air vs iron core induction? Specifically in regards to the construction of speaker crossovers.

Need some advice to a project im thinking. I need a way to read my sauna temp from the cabin about 30 yards away. The sauna has electricity but I dont want to add any cheap chink dc supplies there. Also the circuit should be able to withstand moisture and heat. The heat sensing component should read atleast 120 celcius. I dont want to use an arduino. Thanks

>>1301668
>not using chink supplies
then buy something upscale from mean well
>withstand moisture and heat
then mount it outside
>read 120 celsius
then use a type K thermocouple and specialized ADC
>don't want to use an arduino
then use an esp8266 with a decent external antenna

>>1301668

wireless BBQ thermometer.

>>1301648
Look into core hysteresis, it's something that I'm pretty sure you don't want and it strikes different core materials at different high frequencies. Finding a core that works with audio frequencies shouldn't be a problem, but ferrite, powdered, laminated, solid silicon steel, soft iron, etc. are all things to look into.

>>1301072
What do you use for making circuit drawings?
They're always really nice.

>>1301730

a professional draftsman using custom software.

>>1301697
Thanks senpai

Want to make pic related, have it build on a breadboard to experiment with. The LEDs fade out but they turn on basically instantly. Is there a simple way to also make them fade in?

Diagram in next post

>>1301769

>>1301769

put a cap across each of the LED sections. value determined experimentally: around 470uF is my guess. so, you need 3 aluminum caps; make sure you get polarity right.

>>1301769
That's cute

How often do you order custom PCB for personal projects?

>>1301772
thanks a lot, why aluminum though? I only have electrolytic at hand. Is it because the discharge through the LED's internal resistance is hard on the capacitor?

>>1301777
i've ordered 8 different boards over the past year or so. two had design flaws that i couldn't fix or didn't care to fix, one wasn't producible because i couldn't solder the leds i designed it around without melting some of them. two are waiting on assembly and two more i just haven't bothered programming.

>>1301780
>aluminum though? I only have electrolytic at hand
aluminum = electrolytic

>>1301777
once a year or so but I've only just experienced the pleasure and ease of solder paste stencils. might have to step it up a bit

>>1301783
>aluminum = electrolytic
aluminum ⊂ electrolytic

>>1301841
pedants deserve cancer

>>1301843
This is a thread for noobs. You don't want someone reading your post and thinking any electrolytic capacitor must be aluminum. They have different applications.

>>1301843
pedants ⊂ cancer

>>1301769
>turn on basically instantly
Cs are in series, put them in parallel, closer to sine wave.

>>1301782
and here's #9

>>1301925
the eternal dilemma between fast shipping and boards that aren't fucking purple

>>1301772
Turns out I need more than 1000µF in parallel with each section of 6 LEDs which is just too much to be practical.
>>1301873
This is perfect but can't be done on the tree PCBs

Can you guys tell me what is this thing

pic related

>>1302106
More pics

>>1302108

People always warn abput caps carrying a lethal charge. Where is the line between lethal and non lethal? Like would a 600V 3900uF fuly charged cap kill you?

>>1302106
>>1302108
>>1302109

>>1302161

>>1302051
>just too much to be practical.

if you mean size-wise then know that you can get some pretty tiny 1000uF caps @ 6V if you pull them from motherboards or newer gadgets. like this 470uV @ 6.3V one i pulled yesterday from a dead stereo. (i have lots of 1000uF ones but dunno where i put them.)

>>1302051
>can't be done on the tree PCBs
Maybe there's room for feedback.

>>1302112
It depends on a lot of things. If the current goes through two fingers on the same hand, for instance, it can't kill you but may burn you badly.
Your body has a resistance, the capacitor has a voltage, the current is equal to the voltage divided by the resistance. If the current is too high (something on the order of 100 milliamps) across your heart, it's likely to be fatal.

What should I use for a multi-talker, multi-listener bus for home automation?
At my old place I used simple signaling, one wire per signal. When I ran out of wires in a cat5 cable, I added more cables. This is inelegant and I want to do it right at my new place.
I first wanted to use CAN bus, but there's more overhead in that than I expected, and it's way more than I need. I don't need it to be very fast, I don't need to send long and complicated messages. Most signals are just on/off for relays, or two bytes for a temperature reading.
I just need a low-speed bus with some method of making sure stations don't talk over one another. I'm considering using the CAN transceivers (which I already have) and rolling my own simple ascii-based protocol, in which a station that has a message to transmit while another station is transmitting on the bus simply waits a randomly-determined amount of time after the other station finishes transmitting. The chances of two beginning their transmission at the same time should be negligible.
there's probably a better solution, right?
I'll probably have four or five stations at first, each with a microcontroller communicating with the bus and breaking out a few GPIO lines to whatever it's monitoring and controlling. Could have up to 10 stations in the future. so not a very large network.
Yes I know what an esp8266 is, but I am absolutely not doing this with wifi.

>>1302239
You might want to check out LIN, it's even more limited in speed/bandwidth, but it's ultra low cost and very easy to use: 1-wire, ~20kbit/s. Should cover your needs imho.

>>1302245
Almost but not quite. One master, multiple slaves, no arbitration. I need any station to communicate directly with any other, without having to be polled by the master.

>>1302249
>https://en.wikipedia.org/wiki/List_of_network_buses
Perhaps I2C? Minding the relatively short max length..

>>1302161
Thanks

>>1302254
Definitely not I2C, but that list of busses is quite helpful.

>>1302239
CANbus is all about short messages and multi-master operation, though. What micro are you using for this, and is there a variant available with a CAN controller onboard, or can you add $2 for an MCP2515 type of controller?
If you're not adamantly opposed to over-the-air comms, you might consider nRF24 stuff which is cheap and easy to use.

>>1302171
neat, I'll try to find some of those
>>1302183
I guess it might be doable with a clusterfuck of jumper wires to add the series resistors and circumvent the PCB's traces. By the way, will I need to read a bigboy EE book like Sedra & Smith to be able to analyze circuits like these? The most I can deal with currently is pure RLC networks, but I'd love to understand why >>1301873 and >>1301770 produce the waveforms they do.

>>1302257
>MCP2515
that actually might solve my problem.
I have a few atmega328 chips, so I'm going to use those at least for the first couple of stations.
I am adamantly opposed to radio here. In my experience if I want anything to actually work when I need it, it has to be hard wired.
nRF24 does look pretty cool though.

>>1300007
bro get some jumper wires wtf are u using paper clips and solder wire or some shit?

>>1302414
Those leads are just capacitor/resistor leads, and the thick one is from a diode that I clipped off after soldering it onto a PCB. I typically use solid-core wire for my breadboard wiring (because I can make it really neat looking, like whatever the fuck pic related is (from google)), but sometimes I use trimmed component leads for something to clip an alligator probe onto since I don't have parrot-style clips.

>>1302437
Oh and all the wires you can see except the one on row 16 are still part of components, but I tend to use trimmed component leads for adjacent connections because I have plenty of them and it's not worth the hassle to trim and strip the ends of 2cm of solid core copper.

>>1302439
Quite right anon, quite right, noting wrong with using what's handy and available.

>>1302437
>putting this much effort into a breadboard test

>>1302444
>(because I can make it really neat looking, like whatever the fuck pic related is (from google))
>(from google)

>>1302455
and?

>>1302460
Oh I thought you were implying that it was mine. My mistake. And yes, that is rather a lot of effort.

>>1300371
to add to this:

if you want to efficiently fuel your electronics hobby, learn to start ordering shit early from aliexpress. i literally just bought 40 555 timers for $1.70. 1 fucking 70. free shipping. only caveat is that it takes 30ish days to get here.

i am fine waiting that since I don't need them currently. this is obviously an easy way to just buy a whole bunch of shit that you don't need but just package up shit and sell it on ebay if you need to clean house.

>>1300371
fuck i was also going to say: don't get a fancy variable power supply. just buy a buck/boost converter with some extra features like current limiting and short circuit protection. you arguably won't need that much current and i am currently using a $25 buck/boost converter that can do 0-38V and 0-6A (prob won't deliver 6A but I've never tried and havent needed to). this can power most DC electronics and unless you need AC current, a DC-DC buck/boost converter will handle most beginner's power supply needs.

pic related, it's my current buck/boost converter.

>>1302437
That sexy wire routing...

>>1300564
not shilling for this ebayer but i bought said soldering tips off ebay...

and holy shit these have been fucking magical. i definitely do not have a hakko iron and use some cheap $25 ebay iron that these happen to fit on. the tips that came with my iron pitted like fucking hell after maybe 3-4 uses. i would tin the tip, use it for 15 minutes, clean the tip and retin, and notice that a huge chunk of the tip was now missing.

ive been on the same tip for months now and while i don't solder everyday nor do i extensively do electronics work but i've definitely done enough work with 1 tip to ruin 4 of my older tips. the tip i'm using now still has not pitted anywhere and it still looks brand new if i tin it.

the heat transfer on the very tip is kinda bad but i think that is due to my actual iron and not the tip. i've considered trying to shove something conductive into the tip of the iron so that the ceramic heating element might make better contact/heat transfer to the tip of the iron. bad idea?

I don't know if I should ask here or /sqt/ but you guys seem to know more of electronics.

I just randomly stumbled on this video:
https://www.youtube.com/watch?v=Hwr7jRg0ykg

So I was thinking, the way he wraps the coil, he goes to one end and then wraps in right back, but would the result be more efficient if he ran the wire back to the beginning and winded it to the end the same way the first one was?

I.e. not from point A to point B back from B to A but from point A to B and then again A to B.

Merry Christmas /diy/.

>>1302486
no. the winding direction (ccw/cw) of the coil matters but not whether you wind it up or down the stator. having a single wire going back and then being wound over again shouldn't harm the operation of the solenoid but will distort the winding and the resultant field slightly for no benefit.

stupid question:

do i need enameled copper wire for making coils? or can i use bare copper wire?

>>1302536
enamel is only used because it permits tighter windings than standard insulation. you can use bare copper if you're not going to have two turns touching each other.

>>1302437
if you want cheap solid core wire, you can usually find it under 'telephone wire' in hardware shops. i picked up like 20ft of dual strand solid core 20 awg wire. fits perfectly into breadboards. i think it was like $0.35/ft.

>>1302239

I know you say multi-master, but if you can tweak your design for single master, I highly recommend RS485. It does not get much simpler or lower overhead, or more industrial, and modbus is an easy to implement standard wire protocol.

>>1302548
>solid core 20 awg wire. fits perfectly into breadboards

20 gauge wire will stretch out the springs on a breadboard, just like a big nigger dick stretches out your white boipussy. 24 gauge is what you want. it also happens to be how actual telephone wire is sized.

What is a directional coupler and how does it work?

What is a 3dB hybrid coupler and how does that differ from a directional coupler?

>>1302587
how many points is this assignment worth?

>>1302548
>$0.35/ft
That's awful, more than $1 a metre. I got a "Economy Breadboard Jumper Kit" bundle for $0.12/ft at my local overpriced electronics shop, and I'm sure I could do better online, provided shipping is free for that amount (was 2m of 5 different colours each).

>>1302581
Is that what twisted pair typically is in that 30m reel of Cat5e I've got lying about?

>>1302605
Uh, zero? In case you haven't realized it's Christmas today, finals ended last week so this can't be schoolwork. This information is purely for a personal project.

>>1302612
>finals ended last week
Wow, sucks to be in the northern hemisphere. I've been on holiday for almost two months and boy has it been sunny. Nothing quite like getting a sunburn over a Christmas barbecue.

>>1302618
I'll make sure I brag to you about my holiday when July comes around. By the way, we get three months in Freedomland, really 3.5 since most spring semesters end in the first or second week of May.

Just got a Rigol DS1054Z and I'm stoked to get it back to my projects. What's some cool stuff I can do with it that I might not know about, besides the bandwidth hack?

>>1302621
Pretty much the same here, we start again in the beginning of March.

>>1302439
mein neger

>>1302587
magic

>>1302609
two strands, bill
I bought a 100ft spool of 24awg solid core ages ago and I don't care so much about presentation or exact length. reusing my wire carefully, there's still more than half left.
>cat5e
solid TP network wire is typically 24awg or 26awg.

>>1302644
better gifts and holiday than fireworks
t.slightly surprised nobody in my white-trash neckinnawoods shot off fireworks for Christmas

Is there a way to calculate the total current output of a source for a certain period of time in LTspice?

Lets say 9V battery total current draw over 30 seconds?

>>1302550
It really needs to be multi-master. Remote stations should be able to signal each other in response to events, like a button press, temperature change, or motion detection, without having the master poll them regularly.
also, that way, parts of the system could still work if the main controller is down.

really stupid question but i'm shit at electricity

why is the output voltage 0? surely for curent to flow in a circuit there has to be a voltage between any two points (current wont flow from 0V to 0V)

>>1302862
the output voltage should be less than one but greater than zero in your case. regardless though just because the nodes you've chosen to probe don't have a measurable voltage across them doesn't mean there's no voltage differentials, it just means you're probing a meaningless spot.

>>1302862
In real life that voltage will not be zero. the diode has a voltage drop across it.
But you can have a current with zero voltage. Remember that current times resistance, if your resistance is 0, there's no voltage either. nothing actually has zero resistance except superconductors, but in most small-signal circuits you can assume that wire has no resistance. If you measure the voltage between two points on the same wire, you get 0 or very very close to 0, even though there's current flowing through the wire.

>>1302865
why should it be less than 1? shouldn't voltage slowly decrease from 5V to 0 (disregarding the drop across the resistor) as you travel around the circuit? (with respect to ground terminal)

>>1302867
no, that will only happen when measuring across a uniform resistance like a wire short. it's the basis on which potentiometers operate. in this case you have a nonuniform resistance that'll suddenly drop ~4.3v between its terminals, a magic semiconductor that will drop ~0.7v, and then very small (immeasurable for you) voltage gradients as you described as you probe across the rest of the wiring. you're not strictly wrong, that effect is just completely swamped by the components.

>>1302867
a diode has a forward voltage drop. It's dependent on the current through the diode, but not linearly. For most common diodes it's about 0.7 volts. The voltage across the resistor is then 5 - 0.7, 4.3 volts.
4.3 across the resistor, 0.7 across the diode. the voltage drops from 5 down to 0.

>>1302872
So IRL Vout would be 0.7V, but because this is an ideal diode, it's 0?

>>1302874
Yes. if you're going to assume it's an ideal diode, then all the voltage is dropped across the resistor and the diode has 0 volts across it.
There are no ideal diodes, though, if you make a habit of assuming they're ideal you're going to have troubles.

>>1302875
alright, i get it

thanks /diy/

Why the fuck can't I get this LED to work? Am I retarded?

This is an oddly specific question but I still hope someone with greater experience then mine will be able to help me.
So I've connected digital outputs of my arduino uno to a DAC http://www.. ti.com/lit/ds/symlink/dac0832.pdf , and as in the typical application I've connected the 2 outputs to an op amp http://www.. ti.com/lit/ds/symlink/lm741.pdf .
I'm basically trying to make a function generator but the output is severely jittery and unstable. I've read that one of the causes of unlinearity is the voltage offset of the op amp, but connecting the 10k potentiometer to the offset null pins as suggested in the data sheet and nudging it literally does nothing. What could be the cause of this?

>>1302916
Remember, all the points in one row are on the same potential, so the way you put your resistor you've effectively shorted it. Two different ends of the resistor should go into different rows of the breadboard.

>>1302624
Pls respond

I know some of you guys have a DS1054Z

>>1302916
That's not how breadboard works.
Power supply rail is separated btw.

>>1302918
single or dual supply?
clean power supply(ies) and reference, of course?
what's your write sequence look like?
what's your other Iout tied to?

>>1302920
>>1302924
How come this one still doesn't work then?

>>1302928
That's a tough one. Maybe it's because your power supply isn't connected to the circuit.

>>1302928
where are you connecting power to your load? you need a jumper from the power rails to the main body of the breadboard. the power rails connect vertically (assuming you are looking at the board so that it is longer than it is wider).

the main body has rails that go perpendicular to the power rails but they never intersect. you must bring the connections from the power to the body.

>>1302928

>>1302926
>single or dual supply?
im doing dual supply of the op amp I've made a +9V and a -9V rail on my breadboard using two 9V batteries
>clean power supply(ies) and reference, of course?
power supplies are from the batteries and so I though they were clean but I've tried putting 0.1uF capacitors as decouplers at all the supply pins and there's no improvement. The only improvement I get is from connecting 2 0.1uF caps in parallel from Iout1 pin to ground. My reference is GND pin from the arduino and two ends of two batteries, connected of course, so I can create those rails.
>what's your write sequence look like?
I'm just switching the output of the 8 pins through the PORTD byte, from 0x00 to 0xFF for the square signal, and cycling through a lookup table through a for loop for saw and sine signals
> what's your other Iout tied to?
I've tied Iout1 to the non-inv input and Iout2 to the inv input of the op amp as sudgested in the data sheet
Thanks for looking into this anon.

>>1302928
>>1302933

pic related. ignore the push button and i excluded a resistor since i have a boost/buck converter that can deliver 2.2V

>>1302936
batteries are pretty clean.
>2 0.1uF caps in parallel
that's a lot more cap than you should need
>reference
are you creating a good solid GND reference? pic related
>switching 8 pins
not sequencing ILE, WR1, WR2? does that even work? is the 0830 the part you're using?
>tied
are you tying one of the Iouts to your ground reference?

>>1302941
What's that thing you use to supply power to the whole board? Looks handy.

>>1302949
if you're talking about the blue thing, that's just an arduino pin extension. it connects to my arduino and allows for more pins to attach to GPIO pins. it actually does plug into the power rails and can deliver power from the arduinos 5V Vcc.

but i wasn't using that for this. i was simply using a buck/boost converter which steps up/down from my 9V power source to 0-38V.

my buck/boost converter is actually already posted above so i cant post it again but it's just a small little device that i paid $25 for

>>1302949
there are breadboard-ish power supplies, like pic related

>>1302946
>not sequencing ILE, WR1, WR2? does that even work? is the 0830 the part you're using?
ive just tied wr1 wr2 cs and xfer to ground, while tying ile to high
My setup is basically pic related

>>1302964
except I've also setup an 10k potentiometer, with the middle pin connected to -9v and the outer pins to offset null pins of the op amp

>>1302964
hunh. okay, I guess they are transparent latches
the only other thing I can think of is, are you using the "Rfb" feedback resistor built into the chip?

>>1302973
Yea using that too. I just don't get the source of all that jitter and noise. All the similar projects I've found online just plug in the dac write a few lines of code and it turns out great while i get a complete mess of a signal.

REEEEEEEEE I think I'm about to give up

>>1302978
Check your polarity.

>>1302980
I don't have a multimeter and don't know how that would help.

>>1302982
Diodes only conduct in one direction

>>1302978
looking at my arduino, i think you've hooked it up slightly wrong. i think you're on the digital side and there is no vcc on my arduino on the digital side. digital GPIO pins do output power but only if they're programmed to. go to the pins on the other end of the board where it should have 5v VCC and a couple of GND pins. i'm basing this on the fact that your pins are connected on the side of the reset button but your arduino layout might be different from mine (but i think they're usually mostly similar in layout).

if that doesnt work...

make sure that the LED's positive (cathode leg which is usually LONGER than the anode) leg is connected to the vcc of the power source and that the negative goes to gnd.

make sure the resistor isn't restricting too much power. LEDs have a minimum Vf required to turn on.

make sure the LED isn't burnt out.

make sure the arduino is actually delivering power. you'd need a multimeter for this but you stated that you don't have one. you can actually make a voltmeter with an arduino but that might be just another problem for you at this point in time.

>>1302986
HOLY SHIT.
I'm fucking retarded.

>>1302987
so you got it working? i couldn't see your problem earlier but that seemed to be the issue after seeing it with the arduino on screen.

>>1302986
>positive (cathode leg which is usually LONGER than the anode
anon pls

>>1302988
Yep, plugged into the wrong side, thanks.

>>1302989
anon is right sorry im retarded cathode = negative & anode = positive. luckily the wording shouldn't have too much bearing on the rest of the post

Has anyone here used the DSO DS211 oscilloscope? I got one for Christmas, and I'm trying to update the firmware on it, but it's not letting me put the files on it, it just fails, restarts, and now it won't boot. Anyone have any ideas, or did I get a bad one?

How do I avoid ending up with lopsided pins like this when soldering pins onto a board that only as pins on one side?

I tried putting folded papers under the side that has no pins (it's impossible to find a material that is exactly the thickness of the height required to make the pins stand at 90 degree angle), but then I had the pins lopsided on the other side as the paper unfolded the second I stopped pressing down on the board and then unfolding paper pushed the board up.

what

>>1303204
put a solder blob on the copper side under one pin. then put the headers in their holes and push on them lightly using your fingernail on the plastic body. then just tap the blob with your iron. the headers will move into place and be held there as the blob solidifies. you can then do the rest of the pins.

my attempt at making a 12v to 200v boost converter from shit i had sitting around. it "worked", but the fet was too high resistance so it only managed to get up to ~180v with load and then slowly dropped as the fet heated up. i might be able to solve the issue by doubling the switching frequency to 200kHz, but i haven't thought it through and it's late. at least i got to light up a nixie, if only for a few seconds.

>>1303241
>solder blob
Are you talking about solder paste?

>>1303247
no, literally just feeding solder onto the pad to form a blob. it's to free your hand from having to hold solder so you can push the headers into place with it while you apply the iron. you can also use an alligator clip to hold them if the orientation lets you, but i prefer my method.

>>1302624
Measure, view, record and analyse waveforms, are you expecting magic?

>>1303197
try a different host OS? the FAT DFU is kinda picky on some of those ARM SoCs iirc

>>1303244
obvs you should heatsink that better, as in use more paperclips

>>1302916
yes

>>1303244
im no expert, but common problem is that the fets dont turn off fast enough.

some switching controllers dont sink the capacitive charge of the fet fast enough so it droops out in stead of cuting quickly, meaning heat dissipation is increased.
some designs have dedicated bjts or even darlingtons just to sink the shit out of that fets gate.

>>1303244
>>1303327

here is an example.

you might already be doing this, hard to tell in the pic.

>>1302946
>batteries are pretty clean.
well there is no supplied noise, that is true.
but with the significant output impedance of batteries, voltages slew and crosstalk happens easily without a decent set of caps.

>>1303244
please tell me you're using a schottky for your freewheel diode

tips on cutting perf boards? i usually use my dremel but it creates a fuckload of dust. sometimes i score it with a razor but it doesnt work well all the time

>>1303327
the gate drive is fine, especially at 100kHz. it's just a 5 ohm fet which means it's probably 10 ohms at temperature. i think i'll just solder a few onto each other.

>>1303358
not at 200v i'm not. it's just a fast recovery diode.

>>1303372

i use side cutters to start the cut, then just snap by bending.
when i need a complex shape, then i use a coping saw, hacksaw, or jigsaw.

I have an appliance which stops operating when the battery voltage drops below ~8,0 Volts. I'm looking for a low-power boost converter IC for regulating the voltage a 9-Volt battery at a constant level as its discharged.
I currently have MAX1723 and NCP1402SN50T1 but those have max. input voltage of just 6 V which is too low for a 9 V battery.
Any recommendation for a boost IC? Small size & internal switching transistor would be preferred.

>>1303373
>200V schottky
kek, good call. if the inductor is saturating, turning the freq up will help, at the cost of slightly increased switching losses, where parallel FETs would help.

>>1303433
MT3608 takes up to 24V input for up to 28V output and is easily available on our dear leader ali.

>>1303372
if they aren't the double-sided kind you could use a paper cutter, either the guillotine kind to chop (fast) or the rolling blade kind to score a break line (slower).

>>1303244
I built this >>1303329 basically with a few small modifications and it works pretty well. I made the output variable and it can do from 70-270V. My only gripe with it is it can't supply much current. At about 170-180V I was pulling ~20-30mA max. Those bar tubes take about 10mA full scale and I'd like to run 10 of them plus some regular numerical tubes. I need 100mA, 200mA to be safe and I've yet to find a good DC-DC converter that will do that. I'm looking at flyback converters but I'm having trouble finding suitable off the shelf transformers and I'm not really experienced with designing my own. Not to mention to get the max output current I want I was looking at max input currents of something like 7A at 12V which is too high to be acceptable. I'll probably just have to give up and multiplex the bars.

>>1303459
i ordered >>1301925 which uses a 1:4 C8100 flyback available off digi. designing your own is easy if you're not picky about insulation but it's more expensive than that one.

>>1303465
c8100 comes back with a lot of results and the manufacturer uses a different PN so the digikey number is 308-2269-1-ND

>>1303465
>>1303467
i keep forgetting things in my posts. the easy way to design a flyback transformer is to simply calculate the core's energy storage at your maximum on-time, plus margin, and then multiply that by your switching frequency to get its maximum theoretical power throughput. most ferrites sold on digikey are EPCOS cores. EPCOS provides coefficients K1 through K4 in most of their E core datasheets which can be used to calculate the cores' maximum stored energy, which is constant regardless of turn count.

for example, take an EFD20 core set with a 1mm total gap. if you plug the datasheet K coefficients for 100C into provided formulas, you can find that the core has a maximum stored energy of 620uJ. assume a 30% debit for saturation, so 434uJ. if you multiply that by a 250kHz switching frequency you get a maximum output power of 108W using that transformer. to minimize core heating (don't bother with steinmetz losses) and account for inefficiency you can apply another 50% debit and feel safe using that core for a 50W converter. the turn count in flybacks is flexible so it's just an optimization for leakage inductance vs interwinding capacitance, reflected voltage, overall efficiency, etc. you can do these calculations for any core without using those mfr specific coefficients but it's more annoying.

>>1303465
>>1303467
I will look into this though I kind of wanted a transformer with two secondaries, the normal HV one and one center tapped secondary with a 2:1 ratio so I can take my +12VDC and make it a split +/-12V supply. I'm also not sure about how to do feedback and maintain isolation. I know feedback windings are used and maybe opto-isolators too but I'm not really sure how to implement it.

>>1303496
i looked into full isolation for that core in particular and it would need a secondary dc-dc with a 60v+ input if you wanted an isolated 12v rail and it's just not practical at that point to use an existing core. if you're just pulling your input off a wall wart you don't necessarily need further isolation. i didn't bother in that board. feedback windings are only necessary if you're isolating and even then they're really just "aux power windings" because they don't provide great regulation on their own so you want an optocoupler anyway. tertiary windings are inherently only quasiregulated but you can roughly calculate the turn count relative to the secondary: (12V+margin)/Vsec_min*Nsec.

pic is an example of "good" isolated feedback, essentially using an op amp on the secondary side to adjust an arbitrary feedback voltage until it gets the output it wants. in this case the tl431 is essentially just that op amp in a more convenient configuration. there's plenty of great whitepapers and ti's flyback controller datasheets if you want better information.

I just got my first oscilliscope, a rigol DS1054. I'm not sure if this is normal but when doing my probe compensation, the compensation signal has noise on the bottom of the wave form but not the top. So on the top a have a really smooth, thin line, and on the bottom I have a really fat noisy line. Any tips?

>>1303566
i have a z but i don't see a difference.

broke my boost/buck converter :(
now it delivers 10v regardless of being turned on or off and it wont go under 10v. also the power setting on it no longer works. anyone have any idea on what it could be? alum capacitors seem fine. thats about all i know

pic related its my converter.

>>1303568
forgot the z, so the noise on the top of the signal is within a range of less than 100mv, where the bottom is over 200mv. Seems like something might be funky, maybe im missing something though, same thing on all of my channels and probes

>>1303578
Switched probe to 1x and now the top and bottom are the same, that mean anything?

>>1303578
i'm getting 20mvpp both pulled high and low. it's a fairly high impedance signal, do you have your scope next to your spark gap generator?

>>1303459
get a 1:1 isolation transformer and just rectify.
lots of 300v for free.

>>1303593
you mean 180v

>>1303584
Nothing nearby, so with 10x i'm getting 60mv at the top and 180mv at the bottom, on 1x im getting 1v on each

>>1303595
how the fuck do you get 180v? halfwave?

220v*1.41 -~1.2v = 309v.
you'll probably get a little lower. but ish 300 depending on a few factors.

>>1303595

oh i get it, you're on the 120v pleb mains.

>>1303601
Mains in Ameriland is 120Vrms or about 170Vp. Also I'm designing this to run off a 12VDC supply so I can use it in the car if I so desire. I can't get 170VAC in there without an inverter.

>>1303605
bro just make an inverter and rectify that

>>1303606
>build something more complex than a DC-DC converter that effectively does the same thing

For what purpose?

>>1303606
yeah, that's dumb

>>1303576
did some more research. there are 4 ICs on this board: 2 MBR1060 schottky diodes, an RU7088 N-channel power MOSFET, and an XL4016E1 step down IC.

the issue is that 10v is constantly outputting from this as soon as its plugged in, not when the start button is pressed. also does not go below 10V. i'm guessing something is wrong with the step down converter (the XL4016E1) but i'm not too sure. i've already ordered all the parts from aliexpress. anyone have any ideas?

Waiting on components like... ZZzzzzZZZZ

found a broken cap in an old TV. i have caps coming in tomorrow in the exact measurement which is 680uf 16v. i was curious though, could i replace it with something like a 220uf 16v cap? or maybe like a 470uf 25v?

i didnt want to ruin my chance to fix it so im still going to wait for the cap that is exactly 680uf 16v but how can i tell how much capacitance/voltage i need for a cap? ive heard you can get away with replacing it with a higher voltage but does this mean i need to find one with lower capacitance? is the end result ultimately based on something like the potential energy inside the cap?

>>1303627
unless you know more about the application you shouldn't replace a capacitor with anything of a lower capacitance. you can give it a shot in this case as it's unlikely to be the end of the world if a 5v rail has more ripple on it or a small overshoot on startup. for reference, a typical 680uF electrolytic can be as low as 430uF before falling out of spec when accounting for tolerance and age. so if you replace it with a new 470uF you'll still have a good chance of being within the design specifications until that cap too ages.

in the synth diy community, there are so many cucks trying to sell shit as if it was gold.

look at this "patching system"
https://www.patch-point.com/dr-wiener-diy-kits/landscape-allflesh

26$ for some jacks and a little plated pcb material?

>>1303629
so how does the voltage come into play? you said the 470uf cap would be fine but it is rated at 25v. does that not matter to a degree?