Charge transport in a pnp transistor is carried out by______________?
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Answer: D. holes
Explanation
A pnp transistor consists of an n-type base sandwiched between two p-type semiconductor regions. In p-type regions, the primary charge carriers responsible for electrical conduction are missing valence electrons called holes. Therefore, current transport across the junctions of a pnp transistor is carried out predominantly by holes. Transistors rely on the controlled injection and collection of charge carriers across semiconductor junction barriers. Doping semiconductor material with trivalent impurities creates an abundance of holes functioning as positive charge carriers. In contrast, npn transistors utilize free electrons as their primary majority charge carriers during operation.
Acceptor ions are fixed impurity atoms embedded in the crystal lattice and do not move to transport charge. Donor ions remain fixed within n-type semiconductor crystal structures and do not contribute to mobile charge transport. Free electrons serve as the primary majority charge carriers in npn transistors rather than pnp devices.
- Subject
- Engineering
- Category
- Electrical Engineering
- Topic
- —
- Difficulty
- medium
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