This question already has an answer here:

My AC adapter reads... Output: +12V DC symbol 12.5A Input: 100-240V~ 50-60Hz 2.5A

I would like some clarification on if i'm reading/understanding this correctly. The input is the range in which the brick will work when I plug it into the wall and the output is what the brick pushes out for the computer (what the computer need to draw to power on when I turn it on). If say I were to have 20 of these same computers plugged in would I trip a standard 120V / 20A breaker in my home?

I know you add the Amps and make sure the total doesn't go over the 20A but am I using the 2.5A that the brick pulls or the 12.5A. Kind of a stupid question but its something that's always confused me when I look at it.


marked as duplicate by Leon Heller, Daniel Grillo, Passerby, Ricardo, Scott Seidman Feb 25 '15 at 19:50

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • \$\begingroup\$ This is definitely on topic but mostly a dupe \$\endgroup\$ – Passerby Feb 25 '15 at 16:00

For worrying about the circuit breaker limit it is the 2.5 amp rating that matters. Thats the maximum amperage it will draw at 120V. Typically it will draw significantly less than that.

The total power is Volts * Amps. Which is why the lower voltage output can provide more current. The total power coming in and going out stays the same, minus the inefficiencies of the power brick itself.


Not the answer you're looking for? Browse other questions tagged or ask your own question.