Use of the -12V pin on a PSU

Thread Starter

M4Xgaming

Joined Mar 15, 2021
3
Hi there, I am trying to build my own bench PSU with an old PSU from my computer and I would like to put a step up/down converter to control my voltage and current output. So the opperating voltage input for this boost module is between 10 and 40V and I think 24V is good enough for my use. Here is the question, can I use the -12V pin from my PSU as the ground and the 12V pin in positive to get 24V without any problem? Thanks for your help
 

Delta prime

Joined Nov 15, 2019
813
Hello there :)welcome to AAC,
You have a +12V Dc and -12v DC supply, it is named Dual Power Supply as we get positive and negative 12v power supply at the same time. Is this correct?
 

AlbertHall

Joined Jun 4, 2014
11,102
Note that the current available from the -12V is generally a lot less than the +12V, so the -12V supply would determine the maximum current you could get from this arrangement.

Also be aware that the computer supply will have the 0V connected to supply earth. Unless your stepup/down converter is isolated this will result in short circuits if you connect and other earthed equipment to your circuit - oscilloscope, signal generator, etc.
 

Thread Starter

M4Xgaming

Joined Mar 15, 2021
3
Note that the current available from the -12V is generally a lot less than the +12V, so the -12V supply would determine the maximum current you could get from this arrangement.

Also be aware that the computer supply will have the 0V connected to supply earth. Unless your stepup/down converter is isolated this will result in short circuits if you connect and other earthed equipment to your circuit - oscilloscope, signal generator, etc.
thanks for your help, I ll take care of that
 

MrChips

Joined Oct 2, 2009
23,069
Hi there, I am trying to build my own bench PSU with an old PSU from my computer and I would like to put a step up/down converter to control my voltage and current output. So the opperating voltage input for this boost module is between 10 and 40V and I think 24V is good enough for my use. Here is the question, can I use the -12V pin from my PSU as the ground and the 12V pin in positive to get 24V without any problem? Thanks for your help
No.
The +12V and -12V supplies on the PSU are already referenced to ground.
 
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