Glossary


TERMS AND ACRONYMS CONTINUED..
See below for the special

VDE (Verband Deutscher Elektrotechniker): A German organization testing for public safety.

Volt: Unit of measurement of electromotive force, electric potential or potential difference (V).

Voltage converter technically has the same definiton as the switching power supply, except the term converter is usually used for a single-stage DC-DC SMPS. A typical
off-line switching power supply may consist of several cascaded voltage converters. The term converter may also imply an incomplete PSU, which may need additional components (filters, protective devices, housing, etc.) to make a complete PSU.

Warm up drift: The change in output voltage that occurs during warm-up from turn on of a cold supply until about 30 minutes after turn on. Warm-up drift is measured at constant load, input line, and ambient temperature and is primarily due to internal components reaching thermal equilibrium.

Warm up time: The time needed, after turn on, for the power supply to reach thermal equilibrium with a constant load. Usually estimated to be about 30 minutes.

Watt: Unit of measurement of power equal to 1 joule/sec (W). DC power can be calculated by multiplying voltage and current.