Q1Power Electronics
Question
2 marks
Plot I-V characteristics of SCR.
Answer
The SCR I-V characteristic has a forward blocking region, a breakover point, a forward conducting region with low voltage drop, and a reverse blocking region.
Failed to load diagram: No description
- Forward Blocking (OFF state): With positive VAK and gate not triggered, only a small leakage current flows until the breakover voltage VBO is reached.
- Forward Conduction (ON state): After triggering (gate pulse or VBO exceeded), the SCR latches ON with a low forward drop of ~1-2 V.
- Holding Current IH: Minimum anode current to remain in the ON state.
- Reverse Blocking: With negative VAK, the SCR blocks like a reverse-biased diode (VRRM = reverse repetitive maximum voltage).