technical terms
VAC
VAC stands for Voltage in Alternating Current. VAC describes a periodic switch in the polarity in equal shares in the negative and positive range. The average over time for the alternating current is thus nil. A typical example of a sine wave-shaped alternating current is the 230V domestic power network.
Watt
Watt is a unit of power and is expressed with a capital W. The Watt is an SI unit and is named after physician James Watt. In physics equations the power in watt is indicated through the letter "P".