So, I'm wanting to make a bench power supply out of an ATX PSU I've got laying around.
I'm already pretty familiar with electronics and wiring and all that so I know how to do this safely, but there's one thing I haven't been able to figure out. What would I use the -12v rail for?
>>957215
>What would I use the -12v rail for?
Circuits that require a split supply, like op-amps, or RS-232 drivers.
>>957221
Ah, okay cool. Thanks anon.
>>957215
You should also bring out the +3.3V rail, and for bonus points, if you dig into the supply itself and find the feedback divider, you could put a potentiometer in there and have some variability of the outputs. You could also cut the sense line connections on the power supply PCB and bring them out to binding posts as well, jumpering them to the appropriate output for run-of-the-mill applications, but allowing you to have remote sensing for high current-draw applications, so the supply would automatically compensate for line loss.
>>957223
Yeah, I'm actually planning to do all that. That's just a diagram I found online because I needed a picture. I haven't drawn mine up yet.
>>957215
Complementer NPN-PNP amplifier
you're gonna be like that 8yo girl that shot her gun instructor with an Uzi. an ATX supply is too powerful as a bench supply, especially for a noob. every time you plug in a transistor backwards, it's gonna explode. every short means your breadboard melts, wires turn white hot, smoke fills the room.
or, you'll blow all your electronics money on replacement fuses.
instead, get a used wall-wart, 10Vac @ 0.5A, with a couple of diodes and caps, and you have a great supply that'll handle lots of projects without any disasters. get another 5V phone charger for digital circuits.
>>957263
Hey thanks for the advice. I do know what I'm doing however. Using an ATX for my bench supply fits my needs and budget at the moment. I'd love to have a proper bench supply like I had access to in the electronics lab but I don't have that kind of money.
>>957223
>you could put a potentiometer in there and have some variability of the outputs
Be careful with this as the components in those often don't have much headroom.
>>957263
or it could be a great project to make his PSU current limiting.
>>957263
I've got a pretty old ATX power supply that i've shorted the leads on several times without consequence. Most shit nowadays has current limiting and short circuit protection. The only PSU I've ever had that failed did so when my house got hit by lightning.
>>958360
Yeah, but he's talking about YOUR circuits. PC PSU pumping 20A to your breadboard, thin wires and components = smoke.
>>958360
>I've got a pretty old ATX power supply that i've shorted the leads on several times without consequence
it's not the dead shorts across the output leads you have to worry about. example: if the 5V output can handle 20 amps, it means that it's happy to pump current into a 0.25-ohm load. so, if the combined resistance of the connecting wires, the breadboard contacts, etc, add up to 0.25-ohms then the PSU's short-circuit protection wont kick in, and you have 100W of heat being dissipated on your workbench and your circuit.
same kind of disaster can happen if your load is made up of a backwards-connected diode, or transistor junction, or a backwards op-amp, or an LED with no current-limiting resistor, etc.
Where were you when OP was wanting? I was at home watching tv when grammar called:
>english is kill
>no
