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Question 20242
JEE Physics · Hard

Semiconductors: NMOS vs PMOS MCQ

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NMOS vs PMOSHardQuestion 20242

Question

In an n-channel MOSFET (NMOS), current flows in the channel when:
  1. A
    Gate voltage is negative relative to source
  2. B
    Gate voltage exceeds threshold voltage V_th (positive)
    Correct
  3. C
    Drain voltage is zero
  4. D
    Source voltage is highest

Correct answer

Gate voltage exceeds threshold voltage V_th (positive)

Explanation

NMOS (enhancement mode): applying positive V_GS > V_th inverts the p-type substrate under the gate, creating an n-channel through which electrons flow from source to drain. Below V_th: channel is absent → off. Enhancement mode devices are OFF by default and turned ON by applying V_GS > V_th.

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