Answer: V DS = V GS - V p (or V GS - Vth).
- A V<sub>GS</sub> = 0, with the gate-source voltage held at exactly zero
- B V<sub>DS</sub> = V<sub>GS</sub> - V<sub>p</sub> (or V<sub>GS</sub> - Vth)
- C I<sub>D</sub> = 0, as if the drain current vanished largely at pinch-off
- D V<sub>GS</sub> > 0, a condition with little relation to the actual pinch-off point
Correct answer: B. V<sub>DS</sub> = V<sub>GS</sub> - V<sub>p</sub> (or V<sub>GS</sub> - Vth)
Explanation: Pinch-off: depletion region extends across channel. V<sub>DS</sub>,sat = V<sub>GS</sub> - Vth. Above V<sub>DS</sub>,sat: I<sub>D</sub> saturates (nearly constant).
Conductors have overlapping bands, semiconductors have a small energy gap that can be bridged by heat or doping, and insulators have a large gap that blocks conduction.
Concept context
Band theory, p-n junction, diodes, transistors, logic gates, and integrated circuits.