Question

The amplification factor of a triode is 20 and trans-conductance is 3 millimho and load resistance$3 \times 10^{4}\Omega$, then the voltage gain is.

• A. 16.36
• B. 28
• C. 78
• D. 108

Answer 1

Answer: (A)

16.36

Answer 2

Using voltage gain

$A_{v} = \frac{\mu}{1 + \frac{r_{p}}{R_{L}}}$ also $\mu = r_{p} \times g_{m}$

$\Rightarrow r_{p} = \frac{\mu}{g_{m}} = \frac{20}{3 \times 10^{- 3}}$

$\therefore A_{v} = \frac{20}{1 + \frac{20}{3 \times 10^{- 3} \times 3 \times 10^{4}}}$=$\frac{180}{11}$=16.36.