Question

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

Answer 1

Answer: (B)

27

Answer 2

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
$A =\frac{36}{1+\frac{10000}{30000}}$
$=\frac{36}{1+\frac{1}{3}}$
$=\frac{36 \times 3}{4}$
$=27$