Semiconducting Devices Question 278
Question: A triode has a mutual conductance of $ 2\times {{10}^{-3}}mho $ and an amplification factor of 50. The anode is connected through a resistance of $ 25\times 10^{3} $ ohms to a 250 volts supply. The voltage gain of this amplifier is
[MP PMT 1989]
Options:
A) 50
B) 25
C) 100
D) 12.5
Show Answer
Answer:
Correct Answer: B
Solution:
Using $ A _{V}=\frac{\mu }{1+\frac{r _{p}}{R _{L}}} $ and $ \mu =r _{p}\times g _{m} $
$ \Rightarrow r _{p}=\frac{\mu }{g _{m}}=\frac{50}{2\times {{10}^{-3}}}=25\times 10^{3}\Omega $
$ \therefore A _{v}=\frac{50}{1+\frac{25\times 10^{3}}{25\times 10^{3}}}=25.$
