Question

In the circuit shown, assume the diode to be ideal. When $V_i$ increases from $2V$ to $6V$, the change in the current is (in $mA$):

• A. zero
• B. $20$
• C. $80/3$
• D. $40$

Answer 1

The correct option is B $20$

Given : $R=150\Omega$

As the diode is ideal, thus potential difference across the diode is Zero.

Let the current in the circuit be $I$

$\therefore$ $V_i-3=IR$

$V_i-3=150I$ $⟹$ $I=\frac{V_i-3}{150}$

Current in the circuit is zero i.e $I_1=0$ for $V_i\le 3$

For $V_i=6V$, current in the circuit $I_2=\frac{6-3}{150}=0.02$ $A$

Thus change in the current $\Delta I=I_2-I_1=0.02-0=0.02A$

$⟹$ $\Delta I=20$ $mA$