The power supply transforms the electrical current, stepping it down from line current to whatever is required by the computer. A |voltage selector switch| on the back of the computer regulates this operation. Often, the |internal fan| is built into the |power supply unit|, as the device can become quite warm. The unit is enclosed in a housing to minimize risk of accidental contact with any of its components. Even so, it is safer to disconnect the |power cable| entirely, not merely shutting the computer off, whenever opening the computer chassis.
