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

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

Tardigrade Admin · Accepted Answer

Current gain, α = ( textPower gain/ textVoltage gain) = (800/840) = (20/21) Now, β = (α/1- α) = ((20/21)/1-(20/21)) = 20 As, β = (IC/IB) ∴ IC = β IB = 20× 1.2 = 24 mA ( Given IB = 1.2 mA)

Q. The power gain for common base amplifier is $800$ and the voltage amplification factor is $840$ . The collector current when base current is $1.2 m A$ is

$24 m A$

$12 m A$

$6 m A$

$3 m A$

Current gain, $α = \frac{Power gain}{Voltage gain}$
$= \frac{800}{840} = \frac{20}{21}$
Now, $β = \frac{α}{1 - α}$
$= \frac{( 20/21 )}{1 - ( 20/21 )} = 20$
As, $β = \frac{I _{C}}{I _{B}}$
$∴ I_{C} = β I_{B}$
$= 20 \times 1.2$
$= 24 m A$ ( Given $I_{B} = 1.2 m A$ )

Q. The power gain for common base amplifier is 800 and the voltage amplification factor is 840. The collector current when base current is 1.2mA is

24mA

12mA

6mA

3mA