Question

The current gain of a transistor in a common emitter configuration is 50. If the emitter current is 5.5 mA, find the base current.

(a) 0.203 A

(b) 0.107 mA

(c) 0.107 A

(d) 0.203 mA

The question was posed to me in semester exam.

I'd like to ask this question from Semiconductor Electronics in chapter Semiconductor Electronics : Materials, Devices and Simple Circuits of Physics – Class 12

Answer 1

Correct choice is (b) 0.107 mA

The explanation: The expression for current gain is given as:

β=\(\frac {I_C}{I_B}\)

IC=50IB

Since, IE=IB+IC ➔ IE=IB+50IB

IE=51IB

IB=\(\frac {I_E}{51}=\frac {5.5}{51}\)=0.107 mA