Category: Motor Control

MOS Controlled Thyristor Symbol

MOS Controlled Thyristor Symbol(MCT): An MOS Controlled Thyristor Symbol is a thryristor-like trigger-into-conduction device that can be turned on or off by a short pulse on the MOS gate. It is a high power, high frequency, low conduction drop switching device and shows a tremendous promise for next generation power electronics. The device was announced […]

Static Induction Thyristor

Static Induction Thyristor(SITH): An Static Induction Thyristor or SI-thyristor is a self-controlled GTO-like on-off device commercially introduced in Japan in 1988. Similar device, known as field-controlled thyristors (FCT) or field-controlled diode (FCD), were developed in USA. The device symbol is shown in Fig. 11.10. It is essentially a P+ NN+ diode. Similar to SIT, SITH […]

Static Induction Transistor Symbol

Static Induction Transistor Symbol(SIT): An Static Induction Transistor Symbol is a high-power high-frequency device and is essentially the solid state version of triode vacuum tube. It was commercially introduced by Tokin Corp, Japan, in 1987. The device symbol is shown in Fig. 11.9. The triode-like characteristics make the device suitable, both in active and switching […]

IGBT Transistor Circuit

IGBT Transistor Circuit or Insulated Gas Bipolar Transistor: An IGBT Transistor Circuit or Insulated Gas Bipolar Transistor is basically a hybrid MOS-gated turn on/off bipolar transistor that combines the features of MOSFET (voltage control features), BIT (fast acting features and high power capability) and thyristor. The device is also known as MOSIGT, COMFET (conductively modulated FET), or […]

Power MOSFET Symbol

Power MOSFET Symbol: The power metal oxide semiconductor field-effect transistor (MOSFET) is a device derived from the field effect transistor (FET) for use as a fast-acting switch at power levels. Unlike the bipolar transistor which is current controlled, the MOSFET is a voltage controlled device. The main terminals are the drain and source, the current […]

Power Darlington Transistor Circuit

Power Darlington Transistor Circuit: Power Darlington Transistor Circuit – A Darlington-connected transistor pair is shown in Fig. 11.6. The current gain of the power transistor can be considerably improved if the base drive Base current is obtained from another transistor. This is called a Darlington arrangement. The driver transistor can be incorporated on the same […]

PNP Power Transistor Circuits

PNP Power Transistor Circuits: PNP Power Transistor Circuits are now available in ratings suitable for motor control. This device is a 3-layer p-n-p (or n-p-n) structure, as shown in Fig. 11.5. This type of transistor is known as a bipolar junction transistor (BJT). In normal operation the emitter-base junction is forward-biased and the collector-base junction […]

Gate Turnoff Thyristor Symbol

Gate Turnoff Thyristor Symbol: A Gate Turnoff Thyristor Symbol (GTO), unlike the SCR, has the additional capability that it can be turned off by injecting negative gate current pulse. This is because of its highly interdigitated gate emitter which permits the diversion of PNP collector current by the gate and thereby break up the current […]

Silicon Controlled Rectifier Construction and Working

Silicon Controlled Rectifier Construction and Working: This semiconductor switching device is also known as a thyristor. It is a 4-layer, 3-junction, bistable (ON and OFF) semiconductor switch. The terminal to the outer p­layer is the anode, the terminal to the outer n-layer is the cathode and the terminal to the inner p-layer is the gate […]

Semiconductor Rectifier Diode Definition

Semiconductor Rectifier Diode Definition: Semiconductor Rectifier Diode Definition – The main devices normally employed for motor control are diode, silicon-controlled rectifier (SCR) or thyristor, triac, diac, power transistor, etc. These devices are categorized as per their structure: 2-layer devices such as diode (silicon rectifier), S­layer devices such as transistors, 4-layer devices such as thyristors etc. […]