Lec_Presentation_SCR [P1].pdf - Thyristors Dr A S Nazmul...

Thyristors
Dr. A. S. Nazmul Huda
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Thyristors are classified as follows:
1. Phase-controlled thyristors [or Silicon-controlled rectifiers (SCRs)]
2. Fast switching thyristors
3. Gate-turn off thyristors (GTOs)
4. Bidirectional triode thyristors (TRIACs)
5. Reverse-conduction thyristors (RCTs)
6. Static induction thyristors (SITHs)
7. Light-activated silicon-controlled rectifiers (LASCRs)
8. FET-controlled thyristors (FET-CTHs)
9. MOS-controlled Thyristors (MCTs)
10. MOS turn-off thyristors (MTOs)
11. Bidirectional phase-controlled thyristors (BCTs)
12. Emiter turn off (control) thyristors (ETOs)
13. Integrated gate-commutated thyristors (IGCTs)

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A thyristor is a solid state power semiconductor device.
 It has four alternating layer and three junctions J
1
, J
2
, J
3
of N type
semiconductor and P type semiconductor material.
 A thyristor has three terminals. Namely anode, cathode and gate.
 Thyristor acts as a bistable switch, conducts when its anode is made
positive with respect to cathode and gate signal (between gate terminal and
cathode terminal) is applied. [
conducting when the gate receives a current trigger, and
continuing to conduct until the voltage across the device is reversed biased, or until the voltage is
removed (by some other means)]