In common base circuit of a transistor , current amplification factor is `0.95`. Calculate the emitter current , if base current is `0.2` mA

Options

A. 2 mA
B. 4 m A
C. 6 mA
D. 8 mA

Answer

B

Explanation

Given `alpha = 0.95 , I_(b) = 0.2` mA
As `" " alpha = (I_(c))/(I_(e)) = (I_(e) - I_(b))/(I_(e)) = 1 - (I_(b))/(I_(e))`
`implies (I_(b))/(I_(e)) = 1 - alpha = 1- 0.95`
`implies (I_(b))/(I_(e)) = 0.5 implies (0.2)/(0.05) mA = I_(e)`
`implies I_(e) = 4 mA`