Breakdown Diodes MCQ’s

This set of Electronic Devices & Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Breakdown Diodes”.

1. Which of the following are true about a zener diode?
1) it allows current flow in reverse direction also
2) it’s used as a shunt regulator
3) it operates in forward bias condition
a) 3 only
b) 1 and 2
c) 2 and 3
d) 2 only

2. When the voltage across the zener diode increases_________
a) temperature remains constant and crystal ions vibrate with large amplitudes
b) temperature increases and crystal ions vibrate with large amplitudes
c) temperature remains constant and crystal ions vibrate with smaller amplitudes
d) temperature decreases and crystal ions vibrate with large amplitudes

3. A zener diode works on the principle of_________
a) tunneling of charge carriers across the junction
b) thermionic emission
c) diffusion of charge carriers across the junction
d) hopping of charge carriers across the junction

4. For the zener diode shown in the figure, the zener voltage at knee is 7V, the knee current is negligible and the zener dynamic resistance is 10Ω. If the input voltage (Vi) ranges from 10 to 16 volts, the output voltage (Vo) ranges from?


a) 7 to 7.29V
b) 6 to 7V
c) 7.14 to 7.43V
d) 7.2 to 8V

5. The zener diode in the circuit has a zener voltage of 5.8V and knee current of 0.5mA. The maximum load current drawn with proper function over input voltage range between 20 and 30V is?


a) 23.7mA
b) 20mA
c) 26mA
d) 48.3mA

6. The 6V Zener diode shown has zener resistance and a knee current of 5mA. The minimum value of R so that the voltage does not drop below 6V is?


a) 1.2Ω
b) 80 Ω
c) 50 Ω
d) 70 Ω

7. In the circuit below, the knee current of ideal zener diode is 10mA. To maintain 5V across the RL, the minimum value of RL is?


a) 120
b) 125
c) 250
d) 100

8. In the given limiter circuit, an input voltage Vi=10sin100πt is applied. Assume that the diode drop is 0.7V when it’s forward biased. The zener breakdown voltage is 6.8V.The maximum and minimum values of outputs voltage are _______


a) 6.1V,-0.7V
b) 0.7V,-7.5V
c) 7.5V,-0.7V
d) 7.5V,-7.5V

9. Avalanche breakdown in zener diode is ______
a) electric current multiplication takes place
b) phenomenon of voltage multiplication takes place
c) electrons are decelerated for a period of time
d) sudden rise in voltage takes place.

10. The zener diode is heavily doped because______
a) to have low breakdown voltage
b) to have high breakdown voltage
c) to have high current variations
d) to maintain perfect quiescent point

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