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In a conventional reverse blocking thyristor
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- external layers are lightly doped and internal layers are heavily doped.
- external layers are heavily doped and internal layers are lightly doped
- the p-layers are heavily doped and the n-layers are lightly doped
- the p-layers are lightly doped and the n-layer are heavily doped.
Correct Option: D
In many choppers and inverter circuits, an antiparallel diode is connected across an SCR in order to allow a reverse current flow due to inductive load and to improve the turn-off requirement of commutation circuit. The diode clamps the reverse blocking voltage of the SCR to 1 or 2 V under steady-state conditions. However, under transient conditions, the reverse voltage may rise to 30 V due to induced voltage in the circuit stray inductance within the device.
