# And then it doesn’t quite reach

Which of these would be the best description of this text on a computer power supply: INPUT 100-120V ~

A) The power supply is auto switching

B) The input voltage is direct current

C) The power supply provides multiple voltage rails

D) The input voltage can range between 100 volts and 120 volts

E) The power supply outputs direct current

F) My biggest problem is finding the cord

#### The answer: D) The input voltage can range between 100 volts and 120 volts

The INPUT text is specifying the type of power that’s expected to be provided to the power supply, and in this case the input voltage is between 100 and 120 volts. The squiggly tilde (~) is the symbol for alternating current, or AC. AC is the common voltage type that we use in our standard wall power receptacles, and the power supply will output DC (direct current).

##### Want to know more? Watch “Computer Power Specifications.”

Each PC power supply lists a number of different specifications. In this video, you’ll learn how to interpret power supply specifications and how to avoid a voltage mismatch when connecting your computer to a new power source.