Semiconducting Devices Question 112
Question: The relation between a and b parameters of current gains for a transistors is given by
[Pb. PET 2000]
Options:
A) $ \alpha =\frac{\beta }{1-\beta } $
B) $ \alpha =\frac{\beta }{1+\beta } $
C) $ \alpha =\frac{1-\beta }{\beta } $
D) $ \alpha =\frac{1+\beta }{\beta } $
Show Answer
Answer:
Correct Answer: B
Solution:
$ i _{e}=i _{b}+i _{c} $
$ \Rightarrow \frac{i _{e}}{i _{c}}=\frac{i _{b}}{i _{c}}+1 $
$ \Rightarrow \frac{1}{\alpha }=\frac{1}{\beta }+1 $
$ \Rightarrow \alpha =\frac{\beta }{(1+\beta )} $ .
