# Oscillators – 2 MCQ’s

This set of Electronic Devices & Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Oscillators – 2″.

1. What is the minimum frequency at which a crystal will oscillate?
a) fundamental
b) seventh harmonic
c) second harmonic
d) third harmonic

2. A circuit that can change the frequency of oscillation with an application of a dc voltage is sometimes called___________
a) a crystal oscillator
b) a voltage-controlled oscillator
c) an astable multivibrator
d) a Hartley oscillator

3. For a phase-shift oscillator, the gain of the amplifier stage must be greater than ________
a) 19
b) 30
c) 29
d) 1

4. In order to start up, a feedback oscillator requires______
a) unity feedback equal to 1
b) negative feedback less than 1
c) positive feedback greater than 1
d) no feedback

5. An input signal is needed for an oscillator to start.
a) True
b) False

6. At series resonance, the impedance of a crystal is________
a) minimum
b) maximum
c) equal
d) Zero

7. The Nyquist plot combines the two Bode plots of gain versus frequency and phase shift versus frequency on a single plot.
a) True
b) False

8. The lead-lag circuit in the Wien-bridge oscillator has a resonant frequency at which the attenuation is_________
a) 1/2
b) 1/4
c) 1/5
d) 1/3

9. The twin-T oscillator produces a ________ response.
a) low-pass
b) high-pass
c) band -pass
d) band-stop

10. Which of the following improvements is (are) a result of the negative feedback in a circuit?
a) Higher input impedance
b) Better stabilized voltage gain
c) Lowered frequency response
d) Higher input impedance & Better stabilized voltage gain