Zener diode as a voltage regulator — NEET & JEE Questions

Question 1 · difficulty L1 · recall

A Zener diode used as a voltage regulator is normally operated in

• A. reverse breakdown
• B. forward bias below knee only
• C. zero bias
• D. open circuit with no current

Question 2 · difficulty L1 · understanding

The main purpose of a series resistor in a Zener regulator is to

• A. increase Zener voltage without limit
• B. limit current
• C. short the supply
• D. make the diode forward biased

Question 3 · difficulty L2 · understanding

In its regulation region, the voltage across an idealised Zener diode is approximately

• A. proportional to current like an ideal resistor
• B. zero
• C. constant at VZ
• D. equal to the supply regardless of series elements

Question 4 · difficulty L2 · application

A 6 V Zener is connected as a shunt regulator with adequate current. The regulated output is approximately

• A. 0.6 V
• B. 12 V
• C. zero
• D. 6 V

Question 5 · difficulty L2 · understanding

A Zener diode used as a voltage regulator is normally operated in

• A. reverse breakdown region
• B. forward bias below threshold only
• C. zero-bias condition only
• D. open-circuit mode

Question 6 · difficulty L3 · application

If input voltage rises moderately in a properly designed Zener regulator while load is fixed, the extra current mainly

• A. flows through the Zener
• B. forces output to rise by the same amount
• C. stops all current
• D. reverses the load current

Question 7 · difficulty L3 · application

If load current increases while input voltage remains fixed, Zener current generally

• A. increases by exactly the same amount
• B. decreases
• C. remains fixed regardless of load
• D. becomes forward current

Question 8 · difficulty L3 · application

An ideal Zener diode has breakdown voltage 6 V and is regulating properly across a load. The load voltage is approximately

• A. 3 V
• B. 6 V
• C. 9 V
• D. 12 V

Question 9 · difficulty L3 · application

Why is a series resistor connected with a Zener regulator circuit?

• A. To limit current through the Zener diode and drop excess supply voltage
• B. To short-circuit the load
• C. To increase the Zener breakdown voltage indefinitely
• D. To force zero current through the circuit

Question 10 · difficulty L4 · analysis

A 12 V source feeds a 6 V Zener through 300 Ω with no load. Approximate Zener current is

• A. 2 mA
• B. 40 mA
• C. 20 mA
• D. 60 mA