Question

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

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

Answer 1

The correct option is B $20$

When the potential of the point is $2V$, the diode is in reverse bias, and hence the current in the circuit is zero.

When the potential of the point is $6V$, the diode is in forward bias, and provides zero resistance. Hence the diode can be replaced by a wire, and the current in the circuit becomes $i=\frac{6V-3V}{150\Omega }$

$=0.02A=20mA$