Question

The V-I characteristic of a diode is shown in the figure. The ratio of forward to reverse bias resistance is :

• A. $100$
• B. ${10}^{-6}$
• C. $10$
• D. ${10}^6$

Answer 1

The correct option is B ${10}^{-6}$

$V=IR$

$R_f=\frac{V_f}{I_f}=\frac{0.7}{10\times {10}^{-3}}=7\times {10}^{-5}$

In the similar way, $\frac{0.75}{15}=5\times {10}^{-5}$

and $\frac{0.8}{20}=4\times {10}^{-5}$

$\therefore R_f=\frac{0.7-0.75}{(10-15)\times {10}^{-3}}=10$

and $R_b=\frac{V_B}{I_B}=\frac{10}{{10}^{-6}}={10}^7$

$\therefore \frac{R_f}{R_b}=\frac{10}{{10}^7}={10}^{-6}$