# Analog Circuits Questions and Answers – Clapp Oscillator

This set of Analog Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Clapp Oscillator”.

1. Clapp oscillator is an ___________
a) LC oscillator
b) RC oscillator
c) RL oscillator
d) Crystal oscillator

Explanation: Clapp oscillator is a colpitts oscillator which has an extra capacitor series with an inductor. Hence it is an LC oscillator, with 3 capacitors and one single inductor to set its frequency, and the clap circuit is often used as a variable frequency oscillator, by making one capacitor variable.

2. Which type of feedback is used in clapp oscillator?
a) Positive feedback
b) Negative feedback
c) No feedback is used
d) Both positive and negative feedback

Explanation: Positive feedback is present in the clap oscillator, where in the three capacitors form a voltage divider which determines amount of feedback being applied to transistor input.

3. When constructing variable frequency oscillator among clapp oscillator and colpitts oscillator which one is preferred?
a) Colpitts oscillator
b) Clapp oscillator
c) Both of them have equal preference
d) None of them preffered

Explanation: The stray third capacitor in the clap oscillator doesn’t have a negative effect and the frequency obtained is instead more stable and accurate than colpitt oscillator, hence the clap oscillator is preferred for a variable frequency oscillator.

4. In clapp oscillator voltage is divided by using __________
a) Resistors
b) Capacitors
c) Inductors
d) Voltage dividing circuits are not used

Explanation: In clap capacitor voltage divider circuit is achieved by capacitor because it is a modified version of colpitts oscillator.

5. In a clapp oscillator with three capacitor C1, C2, C3, C1 is used as upper capacitor in voltage divider, C2 is used as lower capacitor in voltage divider and C3 is the third capacitor. For perfect operation which of these capacitor should have minimum value?
a) C1
b) C2
c) C3
d) All of them are equal

Explanation: In a Clapp oscillator C3 is much smaller than C1 and C 2as a result, the equivalent capacitance C is approximately equal to C3. For perfect operation C3 should have minimum value.

6. In a clapp oscillator with three capacitor C1, C2, C3, C1 is used as upper capacitor in voltage divider, C2 is used as lower capacitor in voltage divider and C3 is the third capacitor. The frequency of operation will be close to (Assume C1 parallel C2 is C3).
a)
b)
c)
d)

Explanation: Since equivalent capacitance is close to C3 and equation is similar to colpitts oscillator.

7. In a clapp oscillator with three capacitor C1, C2, C3, C1 is used as upper capacitor in voltage divider, C2 is used as lower capacitor in voltage divider and C3 is the third capacitor. For perfect operation of clapp oscillator value of C3 should be __________
a) Equal to C1
b) Equal to C2
c) Equal to C1 parallel C2
d) Very small

Explanation: For perfect operation of clapp oscillator value of C3 should be C1 parallel C2.

8. In a clapp oscillator with three capacitor C1, C2, C3, C1 is used as upper capacitor in voltage divider, C2 is used as lower capacitor in voltage divider and C3 is the third capacitor. Inductance used in the circuit is L. The frequency of operation will be __________
a)
b)
c)
d)

Explanation: The frequency of operation is given . Here effective capacitance is equal to C parallel C2 parallel C3.

9. In the following oscillator which one is more accurate?
a) Colpitts oscillator
b) Clapp oscillator
c) Hartley oscillator
d) Simple LC oscillator

Explanation: The stray third capacitor in the clap oscillator doesn’t have a negative effect and the frequency obtained is instead more stable and accurate than colpitt oscillator.

10. What will be the clapp oscillator frequency if the C1, C2, C3 of clap oscillator is 1μF, 1μF, 2μF respectively and inductance is 1μH?
a) 0.1MHz
b) 0.4MHz
c) 1MHz
d) 4MHz

Explanation: Frequency of clap oscillator is = 3.9 x 105 ie approximately 0.4MHz.
Therefore, frequency is equal to .

Sanfoundry Global Education & Learning Series – Analog Circuits.

To practice all areas of Analog Circuits, here is complete set of 1000+ Multiple Choice Questions and Answers.

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