For the SCR shown, if a forward voltage is applied to the anode and cathode, with the gate open, then which of the following is true?

Question

Question

This question was previously asked in

MPPGCL JE Electrical 28 April 2023 Shift 1 Official Paper

Answer 1

Silicon Controlled Rectifier (SCR)

The given device is a Silicon Controlled Rectifier (SCR), which is a four-layer (PNPN) semiconductor device with three junctions:

J₁ (P-N junction at the anode side), J₂ (N-P junction in the middle), J₃ (P-N junction at the cathode side).

Explanation:

Since the anode (P) is positive relative to the next N-layer, J1 is forward biased.
The junction J₂ has an N-layer at a higher potential than the P-layer. This makes J₂ reverse biased.
The lower P-layer is at a higher potential than the N-layer of the cathode. Thus J3 is forward biased.