Question

If collector current is $120mA$ and base current is $2mA$ and resistance gain is $3$, what is power gain?

• A. $180$
• B. $10800$
• C. $1.8$
• D. $18$

Answer 1

The correct option is B $10800$

$I_c=120mA$, $I_b=2mA$ $\Rightarrow$ $I_e=I_b+I_c$ (emitter current)
$\Rightarrow$ $I_e=120+2=122mA$
Resistance gain $=3$
d.c power gain $={\left(currentgain\right)}^2\times resistancegain$
$={\left(\frac{I_c}{I_b}\right)}^2\times resistancegain$
$={\left(\frac{120}{2}\right)}^2\times 3={\left(60\right)}^2\times 3=3600\times 3=10800$