A device that stores electrical charge. Alternating current capacitors are used to provide reactive power which leads the real power. Direct current capacitors are used to store power by holding charge. Capacitors resist a change in voltage. The unit used to measure capacitors is “farad.” A farad, abbreviated “f” is a very large value, so the more common unit is “microfarad” (0.000001 f) or µf. The relationship between farads and voltage results in the reactive unit “VAR” or “kVAR” which is another unit capacitors are also measured in. (see: Alternating Current; Inductor; Real Power; Reactive Power; Leading; VoltAmp (Reactive); Lagging.)