Transistor

Complementary metal-oxide semiconductors or CMOS devices are coupled complementary MOSFETS in series, configured so that either MOSFET will conduct when the other is turned off. CMOS devices are frequently used as on-off switches in computer logic and memory circuits. CMOS devices use so little power that they allow electronic watches to operate for five years without battery replacement. CMOS devices only require a significant current when the two complementary FETs in series change their conduction state, i.e., a quick pulse of current flows only during each switching action. CMOS chips are commonly used in computer and calculator circuits, and CMOS is equally as common in consumer-type entertainment equipment.