Topic Outline
- MCQs in Theory of Sinusoidal Oscillation
- MCQs in Wien-Bridge Oscillator
- MCQs in Other RC Oscillators
- MCQs in Colpitts Oscillator
- MCQs in Other LC Oscillators
- MCQs in Quartz Crystals
- MCQs in 555 Timer
- MCQs in Astable Operation of 555 Timer
- MCQs in 555 Circuits
- MCQs in Phase-Locked Loop
- MCQs in Function Generator ICs
Start Practice Exam Test Questions
Choose the letter of the best answer in each questions.
1 . An oscillator always needs an amplifier with
- a. Positive feedback
- b. Negative feedback
- c. Both types of feedback
- d. An LC tank circuit
2. The voltage that starts an oscillator is caused by
- a. Ripple from the power supply
- b. Noise voltage in resistors
- c. The input signal from a generator
- d. Positive feedback
3. The Wien-bridge oscillator is useful
- a. At low frequencies
- b. At high frequencies
- c. With LC tank circuits
- d. At small input signals
4. A lag circuit has a phase angle that is
- a. Between 0 and +90 degrees
- b. Greater than 90 degrees
- c. Between 0 and -90 degrees
- d. The same as the input voltage
5. A coupling circuit is a
- a. Lag circuit
- b. Lead circuit
- c. Lead-lag circuit
- d. Resonant circuit
6. A lead circuit has a phase angle that is
- a. Between 0 and +90 degrees
- b. Greater than 90 degrees
- c. Between 0 and -90 degrees
- d. The same as the input voltage
7. A Wien-bridge oscillator uses
- a. Positive feedback
- b. Negative feedback
- c. Both types of feedback
- d. An LC tank circuit
8. Initially, the loop gain of a Wien-bridge oscillator is
- a. 0
- b. 1
- c. Low
- d. High
9. A Wien bridge is sometimes called a
- a. Notch filter
- b. Twin-T oscillator
- c. Phase shifter
- d. Wheatstone bridge
10. To vary the frequency of a Wien bridge, you can vary
- a. One resistor
- b. Two resistors
- c. Three resistors
- d. One capacitor
11. The phase-shift oscillator usually has
- a. Two lead or lag circuits
- b. Three lead or fagcircuits
- c. A lead-lag circuit
- d. A twin-T filter
12. For oscillations to start in a circuit, the loop gain must be greater than 1 when the phase shift around the loop is
- a. 90 degrees
- b. 180 degrees
- c. 270 degrees
- d. 360 degrees
13. The most widely used LC oscillator is the
- a. Armstrong
- b. Clapp
- C. Colpitts
- d. Hartley
14. Heavy feedback in an LC oscillator
- a. Prevents the circuit from starting
- b. Causes saturation and cutoff
- c. Produces maximum output voltage
- d. Means B is small
15. When Q decreases in a Colpitts oscillator, the frequency of oscillation
- a. Decreases
- b. Remains the same
- c. Increases
- d. Becomes erratic
16. Link coupling refers to
- a. Capacitive coupling
- b. Transformer coupling
- c. Resistive coupling
- d. Power coupling
17. The Hartley oscillator uses
- a. Negative feedback
- b. Two inductors
- c. A tungsten lamp
- d. A tickler coil
18. To vary the frequency of an LC oscillator, you can vary
- a. One resistor
- b. Two resistors
- c. Three resistors
- d. One capacitor
19. Of the following, the one with the most stable frequency is the
- a. Armstrong
- b. Clapp
- c. Colpitts
- d. Hartley
20. The material with the piezoelectric effect is
- a. Quartz
- b. Rochelle salts
- c. Tourmaline
- d. All the above
21. Crystals have a very
- a. Low Q
- b. High Q
- c. Small inductance
- d. Large resistance
22. The series and parallel resonant frequencies of a crystal are
- a. Very close together
- b. Very far apart
- c. Equal
- d. Low frequencies
23. The kind of oscillator found in an electronic wristwatch is the
- a. Armstrong
- b. Clapp
- c. Colpitts
- d. Quartz crystal
24. A monostable 555 timer has the following number of stable states:
- a. 0
- b. 1
- c. 2
- d. 3
25. An astable 555 timer has the following number of stable states:
- a. 0
- b. 1
- c. 2
- d. 3
26. The pulse width out of a one-shot multivibrator increases when the
- a. Supply voltage increases
- b. Timing resistor decreases
- c. UTP decreases
- d. Timing capacitance increases
27. The output waveform of a 555 timer is
- a. sinusoidal
- b. triangular
- c. rectangular
- d. elliptical
28. The quantity that remains constant in a pulse-width modulator is
- a. Pulse width
- b. Period
- c. Duty cycle
- d. Space
29. The quantity that remains constant in a pulse-position modulator is
- a. Pulse width
- b. Period
- c. Duty cycle
- d. Space
30. When a PLL is locked on the input frequency, the VCO frequency
- a. Is less than f0
- b. Is greater than f0
- c. Equals f0
- d. Equals fin
31. The bandwidth of the low-pass filter in a PLL determines the
- a. Capture range
- b. Lock range
- c. Free-running frequency
- d. Phase difference
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nice quiz
thanks! :)