Lecture – 2: Power Semiconductor Devices (Switches)
Classifications of Power Electronics devices • In broad sense power electronic devices are classified in to two. These are: I. Vacuum devices: Mercury, arc rectifier, thyratron etc... Seldom used today. II. Semiconductor devices: major power electronic devices.
Classifications of Power Electronics devices based on the degree of controllability 1. Power Diodes 2. Thyristor devices 3. a) Silicon controlled rectifier (SCR) b) Static induction thyristor (SITH) c) TRIAC (Triode ac switch) d) Gate turn-off thyristor (GTO) e) MOS- controlled thyristor (MCT) f) Integrated gated-commutated thyristor (IGCTs) Power transistors a) Bipolar junction transistor (BJT) b) Metal oxide semiconductor field effect transistor (MOSFET) c) Insulated gate bipolar transistor (IGBT) d) Static induction transistor (SIT)
Classification depending on the number of terminals • In terms of their number of terminals: Power electronic devices are divided into two i. Two-terminal devices (diodes): whose state is completely dependent on the external power circuit they are connected to. ii. Three-terminal devices: whose state is not only dependent on their external power circuit, but also on the signal on their driving terminal (gate or base).