Insulated-gate bipolar transistors (IGBTs) are high efficiency and fast switching three-terminal power semiconductor devices primarily used as electronic switches. They are used in switching power supplies in high power applications such as variable-frequency drives (VFDs), electric cars, trains, lamp ballasts, and air-conditioners as well as in switching amplifiers -- sound systems and industrial control systems. IGBT arrays contain multiple devices in one package in full- or half-bridge configurations.