DC Polarity Question

Thread Starter

arfinator

Joined Nov 21, 2010
1
Hey, guys!

This is my first post here, thought I have looked around quite a bit. Everything on here has helped immensely!

I have a AC/DC transformer that outputs both 12VDC and -12VDC relative to the ground. Can I use the -12VDC output without changing anything, or do I need to include something to change that to +12V?

If so, how might I do that?

Thank you so much, and I look forward to your response.

Hess

Please note that as of right now, this is an entirely theoretical project. I plan to have it looked over to ensure my safety and the safety of other users before it is put into practice. :)
 

thatoneguy

Joined Feb 19, 2009
6,359
If it is a dual output power supply, you should have a black jack (-12V), green jack (ground), and Red jack (+12V), or colors similar to that. If you measure between the red and black jacks, a DMM will show 24V.

Usually, -12V is only 1.5A, while +12V can be 1.5 to 40Amps (depending on if you are using an ATX computer supply or basic hobby type supply) The max current from -12V is the limitation on using the 24V supply.

If not interested in "bridging" for 24V, then ensure both -12V and +12V are regulated, you can do this by measuring voltage without a load and writing it down, then hooking up a 12V light bulb, and the voltage should be within 0.1V of unloaded for a regulated supply.

If this doesn't match what you are looking at, please post a photo.
 
Top