Question

For a common base connection, the values of constant collector current and base current are $5mA$ and $50$$\mu A$ respectively. The current transfer ratio $\left(\alpha \right)$

• A. $0.89$
• B. $0.95$
• C. $0.99$
• D. $0.101$

Answer 1

Answer: (C)

$0.99$

Given that:
$I_c=5mA$
$I_b=50\mu A=50\times {10}^{-3}mA$
Hence,
current gain is
$\beta =\frac{I_c}{I_b}$

$\beta =\frac{5}{50\times {10}^{-3}}=100$

Therefore,
$\alpha =\frac{\beta }{1+\beta }$

$\alpha =\frac{100}{1+100}$

$\alpha =\frac{100}{101}=0.99$