Question

In the $CB$ mode of a transistor, when the collector voltage is changed by $0.5$ volt, the collector current changes by $0.05 \,mA$. The output resistance will be :

• A. $10\, k \Omega$
• B. $20\, k \Omega$
• C. $5\, k \Omega$
• D. $2.5\, k \Omega$

Answer 1

Answer: (A)

Here: $\Delta V_{ c }=0.5$ volt,
$\Delta I_{c}=0.05\, mA =0.05 \times 10^{-3} A$
Output resistance is given by
$R_{\text {out }} =\frac{\Delta V_{c}}{\Delta I_{c}}$
$=\frac{0.5}{0.05 \times 10^{-3}}=10^{4} \Omega=10\, K \Omega$