How to Check the Voltage Level on a Computer Power Supply

Connect your computer power supply to a wall outlet and monitor the voltage with a multimeter.

The power supply for your computer transmits electrical current directly from an outlet to your computer or laptop battery. The voltage of such a power source is a measurement of the energy per electrical charge of the device with a live current, or the energy transmitted between two points on the circuit when the power supply is plugged into an electrical source such as an outlet. With a multimeter, you can observe and measure the voltage of your computer's power supply.

Things You'll Need

• Multimeter

Instructions

1. Switch your power supply to the correct mode on the multimeter's dial. This setting can be determined by inspecting the "Input" and "Output" fields on the primary box of the power supply. The "Output" field indicates whether the device has an output of AC (alternating current) or DC (direct current).

2. Connect the probes to your multimeter. The red and black cables and ports are color-coded for your protection.

3. Disconnect the power supply from your computer. Connect the power supply to a wall outlet.

4. Touch the multimeter probes to the opposite end of the power supply, or the end that is normally plugged directly into your computer.

5. Observe the reading on your multimeter. Do not be alarmed if the voltage for the power supply is a little higher than the specified voltage that is listed on the power supply. A slight overcharge of the current is completely normal.

Tips & Warnings

• The multimeter can be an extremely dangerous tool if misused. Do not, under any circumstances, touch one of the multimeter probes to anything else when observing the voltage of your power supply.

References

• Lady Ada: Multimeter Tutorial