A bipolar junction transistor is a type of transistor that uses both electrons and electron holes as charge carriers.

A heterojunction bipolar transistor is a type of bipolar junction transistor that uses different semiconductor materials for the emitter and base regions, creating a heterojunction.

An insulated-gate bipolar transistor is a three-terminal power semiconductor device primarily forming an electronic switch.

Bipolar transistors must be properly biased to operate correctly.