Question

A zener diode of zener voltage 30 V is connected in a circuit as shown in the figure. The maximum current through the Zener diode is:
 

• A. \( 5 \) mA
• B. \( 14 \) mA
• C. \( 9 \) mA
• D. \( 7 \) mA

Hint:

The zener diode maintains a constant voltage in reverse bias.
- Use Kirchhoff’s Current Law (KCL): \( I_{\text{total}} = I_Z + I_L \).

Answer 1

The Correct Option is A

The zener diode operates in reverse bias, and its voltage remains constant at 30V. The current through the zener diode depends on the resistor values in the circuit. 1. Given data: - Input voltage \( V_{\text{in}} = 50V \) - Zener voltage \( V_Z = 30V \) - Resistors: \( R_1 = 5k\Omega \), \( R_2 = 2k\Omega \), \( R_L = 6k\Omega \) 2. Current through \( R_1 \) (Supply Current): \[ I_{\text{total}} = \frac{V_{\text{in}} - V_Z}{R_1} \] \[ = \frac{50 - 30}{5k} \] \[ = \frac{20}{5000} = 4 \text{ mA} \] 3. Current through Load \( R_L \): \[ I_L = \frac{V_Z}{R_L} = \frac{30}{6k} = \frac{30}{6000} = 5 \text{ mA} \] 4. Current through Zener Diode: Using Kirchhoff's Current Law (KCL), \[ I_{\text{total}} = I_Z + I_L \] \[ 10 = I_Z + 5 \] \[ I_Z = 5 \text{ mA} \] Thus, the correct answer is \(\boxed{5 \text{ mA}}\).