Negative grounding: In most types of electronic equipment the negative terminal of the dc power supply is intentionally connected to the metal frame or housing of the electronic equipment. The frame is also connected to the earth or ground (sometimes using the green wire in the power cord). A power supply typically uses a transformer and various electronic rectifiers and filters to convert 110 volt alternating current power into a direct current at a constant voltage (typically 5 volts) needed by the electronic equipment. It would be more descriptive to call this device a