How can you test the output of a power supply?



During normal troubleshooting of a desktop computer, you suspect that the power supply may not be providing enough output to support all of the installed peripherals. What tool can you use to test the output of the computer’s power supply?

A) Multimeter

B) Loopback plug

C) Torx screwdriver

D) Non-static vacuum


The answer: A) Multimeter

The multimeter is the Swiss Army knife of power troubleshooting. If you ever need to know what’s happening with power, the multimeter is probably the best tool in your toolbag.


The incorrect answers:

B) Loopback plug
A loopback plug is used to redirect signals from a communications port back into the same port, allowing you to test that the port can send and receive properly. Loopback plugs aren’t used with power, since you really don’t want power looping back into itself (it could cause the Enterprise to explode!).

C) Torx screwdriver
Specialized screwdrivers might assist you with replacing power supplies, but they won’t help you determine the amount of power output.

D) Non-static vacuum
You should always keep your system free of dust, but the vacuum won’t help you troubleshoot power problems.

Want to know more? Watch “The CompTIA A+ Toolbag.”


Every CompTIA A+ technology professional needs a tool bag with the right mix of diagnostic tools, specialty tools, and cleaning products. In this video, we’ll walk you through the must-have tools that you’ll need for everyday troubleshooting and preventive maintenance.