BJT have three terminal emitter, base and collector. The collector current is the output current. The collector current (Ic) is controlled by base current hence BJT is called current controlled device.
Description : Is BJT unipolar or bipolar Why?
Description : A bipolar junction transistor (BJT) is used as a power control switch by biasing it in the cut-off region (OFF state) or in the saturation region (ON state). In the ON state, for ... base-collector junction is reverse biased (D) both the base-emitter and base-collector junctions are forward biased