Question

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

I have been asked this question in exam.

The doubt is from Clapp Oscillator topic in section Oscillators of Analog Circuits

Answer 1

Right answer is (c) C3

Best 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.