So I have this power supply that gives me these outputs.
Is there any way I can turn this into a -16 and a +16 Volts outputs?
pls respond
>>971388
Making the ASSUMPTION that the +16V rail can sink current as well as source it, simply use the 16V rail as GND. GND becomes -16V and +32V becomes +16V.
But that isn't a good assumption to make because odds are it can't, so...yeah, check first.
>>971409
how the fuck do I check that?
>>971413
Even if it does work that way, which it probably will, you might have issues with grounding and such. I made a little +-12V supply from a similar power brick (mine was 15v and 32v) and some regulator ICs. It worked until I tried to use a circuit that was grounded via an audio jack plugged into my computer. Since the computer's 0v reference is actually the -12v rail on the regulator, you get a short. The regulators probably saved me from putting -12v into my sound card.
>>971417
I just need to power an op amp.
I don't know why these fucking things need to have a negative voltage.
It's a pain in the ass.
>>971420
Use two 9V batteries. Also, depending on what you're doing, you can just take the op amp "ground" from the center node between two resistors in series across a single supply, from which you also power the op amp.
![Image37[1].gif](https://i.imgur.com/sAtECvJ.gif "Image37[1].gif")
>>971423
I'm doing this shit.
Batteries will drain fast and the other thing you mentioned won't work.
>>971417
you're wrong and retarded
You can do +16, -16 and +32, -32.
You can use a regulator to reduce +32 to -16 but i dont recomend it.
The first option will work better
>>972324
how
>>971420
If it is for an op amp then use the +16 and add 2 capacitors, so it will be ±16. And forget about the +32 rail.
>>972328
Something like this.
FORGET about the existance of the +32 rail.
>>972329
Where do I put the capacitors?
Something like this.
Sorry for shitty diagram.
>>972332
you sure that will work?
>>972342
Try it.
Almost Every amp that needs a negative and positive voltaje, will have that kind of power supply.
>>972332
>shitty
>toilet paper
>>972354
Does the ground node have to be connected to an actual ground though?
And what kind of capacitors are those?
Do they have to be electrolytic?
>>972371
Yes, the chasis.
And yes.
>>972372
I don't have a chasis.
Can I use my house's ground?
Keep it without a ground. It should work fine
![1444671216525[1].gif](https://i.imgur.com/hLeSUxq.gif "1444671216525[1].gif")
>>972379
Thanks friend.
I owe you one.
>>972332
You need some fairly low-resistance resistors in parallel with each of those capacitors to make sure the center terminal is exactly half way between the two "real" rails. Also, I hope your drawing is not actually what you built, because you've got "-16v" and "gnd" on the same wire on the bottom, and "gnd" again on the intermediate wire, which would just short that to the bottom wire as well. Use different labels if you're going to have a virtual ground so that it's not so confusing.
Forget it I found two 12 V power supplies that I can work with.
I'll try to delete the thread now.
![tS1_UYIp[1].jpg](https://i.imgur.com/4uVjegx.jpg "tS1_UYIp[1].jpg")
I can't delete the thread.
What would you like to discuss now?
>>972332
Uhh....
How has nobody else noticed that this will only give +/-8V?
>>972407
Unless one of them is a positive ground. ie -12V supply, that isn't going to help you. If you try to stack them you will just short one of them because you'll be connecting the 12V rail of one of them to the ground of the other, and if they are grounded in any way to the mains, it will result in a short.
Try this. You need the resistors to actually set the voltage at the center terminal midway between the rails, the capacitors just serve to stabilize the voltage the same way filter caps in power supplies work. The resistors will probably be need to be reduced in value if your motor is sinking or sourcing any kind of current through the 0V terminal. Those resistors set the maximum current that can flow through the virtual ground. for 1k resistors, it tops out at +-16 mA, assuming a 32V supply.
![pos_neg_volt_diagram_2[1].jpg](https://i.imgur.com/5UggKqu.jpg "pos_neg_volt_diagram_2[1].jpg")
>>972412
I'm doing this and it gives me a positive and negative output.
So it works.
>>972422
Then both of those supplies must be floating. I guess if it works, it works. Have you tried actually hooking it up to the circuit though?
>>972423
Not yet.
They're just common chargers I found.
I don't know what you mean by floating supplies.
But if it doesn't work I'll try the other thing you mentioned.
swap the polarity between the 16v and ground . :)
>>972373
Yes, that's how ground works.
>>972438
No, that's earth.
>>972425
I don't know if floating is the right word, actually, that may describe something else.
I was trying to type a big thing out and draw a picture, but this article describes it better: http://powersupply.blogs.keysight.com/2014/03/what-is-floating-power-supply-output.html
> Americans talking about grounding
Please stop.
The power supply' floating' means its fully isolated from mains supply, neither output is referenced to either input. Take a standard transformer with two windings, there is no reference from input to output. Say the output was a billion volts, you could safely touch one output wire because you would supply the reference (0v hopefully) to the winding, the other end would be a billion volts with respect to you.
There is no such thing as 0v really, you pick the 0v, any voltage you measure is the difference between the two points your measuring.
Ground or earth is just convenient because its literally the ground and provides a reference for cross country power lines and shit. If your supplies weren't isolated or floating you couldn't connect then like that because they would short out.
A voltage divider(two resistors) won't work for any significant load because the current drawn will change the voltage ratio.
Ideally a centre tapped transformer gives you a dual rail supply if you use the centre tap as your 0v or 'ground'
A single winding transformer will also work if you use capacitors to create a virtual reference (check out voltage multipliers, is the same thing really) but the available current is half because each will only charge every cycle instead of half cycle.
You can just buy a switching regulator that gives you a dual rail reference with none of this fannying about.
>>971565
He may be right.
Many microchips use a +/- 12v supply. The +12 powers the chip, and the -12 gets used to bias the logic gates for a 24v range of potential.
That said, most modern computers no longer need the full 24v range.
>>971420
> I don't know why these fucking things need to have a negative voltage.
The ones shown in your circuit don't. But your circuit needs a voltage which is half-way between the two rails.
The easiest way to achieve this is to just get a small IC power amplifier, bias it so that its output is half-way between the rails, and use the output as "ground" in your circuit.
Basically what >>972330 and >>972412 are trying to do, but with a far lower impedance while wasting less power.
Actually, for >>971425 you don't even need a power amp; an op-amp would suffice.
