# RF Oscillators MCQ’s

This set of RF & Microwave Circuit Design Multiple Choice Questions & Answers (MCQs) focuses on “RF Oscillators”.

1. The transfer function of an RF oscillator is given by:

a) A/ (1-AH (ω))

b) A/ (1+AH (ω))

c) A/ (-1+AH (ω))

d) 1/ (1-AH (ω))

2. The criterion on which oscillations are produced in the oscillator circuit is called:

a) Shannon’s criteria

b) Barkhausen criteria

c) Colpitts criteria

d) None of the mentioned

3. _________ is a non linear circuit that converts DC power to an AC waveform of desired frequency based on the oscillator design.

a) Attenuator

b) Amplifier

c) Oscillator

d) None of the mentioned

4. The necessary condition for oscillation in a Colpitts oscillator is:

a) C_{2}/C_{1}=g_{m}/G_{i}

b) C_{1}/C_{2}=g_{m}/G_{i}

c) C_{2}/C_{1}= g_{m}*G_{i}

d) None of the mentioned

5. The necessary condition for oscillation in a Hartley oscillator is:

a) L_{1}/L_{2} = g_{m}/G_{i}

b) L_{1}/L_{2} =G_{i} /g_{m}

c) L_{2}L/L_{1} = g_{m}/G_{i}

d) None of the mentioned

6. Hartley oscillator has inductance values of 12 mH and 4 mH in the feedback section and a capacitor of 4 nF. Then the resonant frequency of the circuit is:

a) 19.89 kHz

b) 25 kHz

c) 45 kHz

d) 12 kHz

7. Colpitts oscillator operating at 50 MHz has an inductor in the feedback section of value 0.10µH. then the values of the capacitors in the feedback section is:

a) 100 pF, 100 pF

b) 100 pF, 50 pF

c) 70 pF, 130 pF

d) 80 pF, 60 pF

8. An inductor is operating at frequency of 50 MHz. Its inductance is 0.1 µH, and then the series resistance associated with the inductor is: (Qo=100)

a) 0.31 Ω

b) 1.32 Ω

c) 1 Ω

d) 1.561 Ω

9. Colpitts oscillator in the feedback section has an inductance of 4 mH and capacitors of 12 nH and 4 nH. Then the resonant frequency of Colpitts oscillator is:

a) 50.4 kHz

b) 35.1 kHz

c) 45.9 kHz

d) None of the mentioned

10. For Colpitts oscillator, the capacitors C_{1} and C_{2} in the feedback network are 1 µF and 25 µF respectively. Then the β value of the transistor is:

a) 35

b) 000.76

c) 25

d) 0.0025