Which one of the operations of $n-p-n$ transistor differs from that of $p-n-p$ transistor?

Which one of the operations of $n-p-n$ transistor differs from that of $p-n-p$ transistor?
  1. The emitter-base junction is reversed biased in $\mathrm{n}-\mathrm{p}-\mathrm{n}$ transistor.
  2. The emitter injects minority carriers into the base region of the $p-n-p$ transistor.
  3. The emitter injects holes into the base of the $\mathrm{p}-\mathrm{n}-\mathrm{p}$ transistor and electrons into the base region of $n-p-n$ transistor.
  4. The emitter injects holes into the base of $\mathrm{n}-\mathrm{p}-\mathrm{n}$ transistor.

Solution

In p-n-p transistors holes are majority charge carriers in emitter hence, the emitter injects holes into the base and in n-p-n transistors electrons are majority charge carriers in emitter hence, the emitter injects electrons into the base region.

Asked in: MHT CET 2023 (10 May Shift 2)

Practice more Semiconductors questions on Aicharya