Q. In a triode valve, the plate resistance is 10000 $\Omega$ and the anode load resistance is 30000 $\Omega$. If the amplification factor is 36, then the voltage gain is
A) 9
B) 27
C) 36
D) 108
Explanation
(b) Voltage amplification (gain) is given by
$A = \frac{\mu}{1 + \frac{r_{p}}{R_{L}}}$
where $\mu\ $is amplification factor, $r_{P}$ is plate resistance and $R_{L}$ is load resistance.
Given, $\mu = 36,$ $r_{P} = 10000\ \Omega$, $R_{L} = 30000\ \Omega$
Putting in the relation, we obtain
$A = \frac{36}{1 + \frac{10000}{30000}} = \frac{36}{1 + \frac{1}{3}} = \frac{36 \times 3}{4} = 27$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.