JEE MainPhysicsSemiconductors
In a Zener diode voltage regulator circuit, the Zener diode has a breakdown voltage of 6 V and a maximum power dissipation rating of 0.24 W . The series resistance is 100 and the load resistance is 300 . What is the maximum unregulated input voltage V_ in that can be applied without damaging the Zener diode?
Options
- A10 V
- B12 V
- C8 V
- D16 V
Correct answer
B. 12 V
Step-by-step solution
The maximum current the Zener diode can safely carry is determined by its power rating: I_ z,max = P_ Z,max V_z = 0.24 6 = 0.04 A = 40 mA Since the Zener diode is in parallel with the load, the voltage across the load is regulated at 6 V . The current through the load resistor R_L is: I_L = V_z R_L = 6 300 = 0.02 A = 20 mA The total current flowing through the series resistor R_s is the sum of the Zener current and the load current. To find the maximum allowable input voltage, we use the maximum Zener current: I_s