Question

The emitter current IE in a transistor is 3mA. If the leakage current ICBO is 5µA and α=0.98, calculate the collector and base current.

(a) 3.64mA and 35µA

(b) 2.945mA and 55µA

(c) 3.64mA and 33µA

(d) 5.89mA and 65µA

The question was asked during an online exam.

This intriguing question comes from The Common Base Configuration topic in section Transistor Characteristics of Electronic Devices & Circuits

Answer 1

The correct option is (b) 2.945mA and 55µA

The best I can explain: IC=αIE + ICBO

=0.98*3+0.005=2.945mA.

IE=IC+IB . So, IB=3-2.495=0.055mA=55µA.