Question

The power gain for common base amplifier is 800 and the voltage amplification factor is 840. The collector current when base current is 1.2 mA is
A. 24 mA
B. 12 mA
C. 6 mA
D. 3 mA

Answer 1

Correct Answer - A
Current gain, `alpha=("Power gain")/("Voltage gain")=800/840 =20/21 `
Now, `beta=alpha/(1-alpha)=((20//21))/(1-(20//21))=20`
As, `beta=I_C/I_B`
`therefore I_C=betaI_B=20xx1.2=24 ` mA (Given `I_B` =1.2 mA)