deciwatt

Deciwatt (symbol dW) is a unit of power in the SI system, equal to one tenth of a watt. It is formed by applying the deci- prefix to the watt (W). Therefore, 1 dW = 0.1 W, and multiples are straightforward: 10 dW = 1 W, and 1 W = 10 dW.

In practice, deciwatt is not widely used in modern specifications. Most measurements employ watts, milliwatts, or microwatts, and RF or audio power levels are often expressed in decibels relative to a watt (dBW) or a milliwatt (dBm). Deciwatt may appear in older documentation, specialized instrumentation, or contexts where tenth-of-a-watt resolution is convenient.

Examples: an output of 0.3 W equals 3 dW, and 0.05 W equals 0.5 dW (50 mW). The deci- prefix scales consistently with other SI units, so the relationships to larger or smaller units follow the standard metric conversions (1 dW = 100 mW; 1 W = 10 dW).

See also: watt, milliwatt, decibel-watt (dBW), decibel-milliwatt (dBm), SI prefixes.