# Power Supply Question

#### smgvbest

Joined Dec 29, 2005
2
Hi everyone,

I seem to have forgoten some very basic stuff and need someone to jog my memory

If you have a power supply providing say -12V @ 1Amp and +12V @ 5Amp

You then connect -12V to the negavtive input on your device and +12V to the Positive input on the device to get 24V

What is the total current capable of being supplied to the device?
If both supplied equal current such as 1amp then answer would be 24V @ 1amp

But they're not, so how do you figure the total available current that can be supplied by the Power Supply?

Thank you

#### peajay

Joined Dec 10, 2005
67
> What is the total current capable of being supplied to the device?

6 amps...

> If both supplied equal current such as 1amp then answer would be 24V @ 1amp

Oh, well, if you're going to do it that way...

You can get 5A out of the +12v, and 1A out of the -12v, which is 6A total, which you could get if you drained both voltages to ground. If you're draining one into the other, then you're limited by whichever has the smallest current rating. So you'll get 1 amp if you connect something between -12 and +12 and ignore the ground, since attempting more current would exceed the rating on the -12v.

#### alim

Joined Dec 27, 2005
113
Originally posted by peajay@Dec 29 2005, 02:27 AM
> What is the total current capable of being supplied to the device?

6 amps...

> If both supplied equal current such as 1amp then answer would be 24V @ 1amp

Oh, well, if you're going to do it that way...

You can get 5A out of the +12v, and 1A out of the -12v, which is 6A total, which you could get if you drained both voltages to ground. If you're draining one into the other, then you're limited by whichever has the smallest current rating. So you'll get 1 amp if you connect something between -12 and +12 and ignore the ground, since attempting more current would exceed the rating on the -12v.
[post=12750]Quoted post[/post]​
Hi, To get 24volts you will would have connected the coils in series, in a series circuit the current is the same,thus while one is capable of 5amps you are limited to 1 amp,the capability of the lower one.alim