Anyone good at electronics?

chuck990 · 20 Mar 2011 at 19:36

Simple question I hope, (google hasnt helped yet but i may not have typed the right thing)

What i want is to provide +/-12 volts to a circuit i built. I think i'm right in saying that DC power supplies provide only +v and 0v so i wanted to know how to get the -v i need (for op-amps in an audio circuit, i built it for a-level coursework but now want to take it home to use and have no way to power it...)

Think i've come up with one possible solution, set up 24v worth of batteries in series and connect the middle to ground, this would work no?

p4radox · 20 Mar 2011 at 19:40

This is a useful article about virtual ground circuits:

http://tangentsoft.net/elec/vgrounds.html

I've previously used a buffer to provide the virtual ground and it worked pretty well, see the "Simple Buffered Virtual Ground Circuits" section in the link.

chuck990 · 20 Mar 2011 at 19:50

thats brilliant

thanks a lot, think i'll risk trying the bufferless circuit with just resistors, just have to make sure i keep my batteries nice and fresh

BullBoyShoes · 20 Mar 2011 at 20:32

Op-amps dont always need a dual supply, it really depends on how you have it configured in your application. care to tell us a bit more about it?

chuck990 · 20 Mar 2011 at 20:45

well im taking four inputs into a summing amp, putting the signal through variable filters (one bass cut, one treble cut) and then through a power amp (some chip with a strange collection of fets) and out in one output.

It's basically to save my lazyness, my speakers have one 3.5mm input and i have 4 things i want to run off them, with this system i have all 4 plugged in at once (with switches to turn them on/off) nad some added extras in the tone and volume controlls.

OzyOly · 20 Mar 2011 at 21:10

chuck990 said:
well im taking four inputs into a summing amp, putting the signal through variable filters (one bass cut, one treble cut) and then through a power amp (some chip with a strange collection of fets) and out in one output.

It's basically to save my lazyness, my speakers have one 3.5mm input and i have 4 things i want to run off them, with this system i have all 4 plugged in at once (with switches to turn them on/off) nad some added extras in the tone and volume controlls.

Sounds a bit like my second year Uni project. Good luck with getting it powered.

PhillyDee · 20 Mar 2011 at 23:54

Pretty sure you can make a voltage divider, currently at work, so cannot really spend time searching for what I really mean!