Electronic Devices Question 189
Question: The amplification factor of a triode is 20 and trans-conductance is 3 milli mho and load resistance $ 3\times 10^{4}\Omega $ , then the voltage gain is
[RPMT 1996]
Options:
A) 16.36
B) 28
C) 78
D) 108
Show Answer
Answer:
Correct Answer: A
Solution:
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.
