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Oscillators Question & Answers

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This article lists 100+ oscillators MCQs for engineering students. All the oscillators Questions & Answers given below include a hint and wherever possible link to the relevant topic. This is helpful for the users who are preparing for their exams, interviews, or professionals who would like to brush up their fundamentals on the oscillators topic.

Oscillators are devices known for converting the signals DC into AC. Any amplifier can be converted to an oscillator by giving a feedback connection. An amplifier for amplification prefers negative feedback and provided with positive feedback results in oscillations.

The signal produced at the output is continuous it can be a sine wave, square wave, or triangular wave. Based on frequency these oscillators are classified as Low-frequency oscillators, Audio frequency oscillators, and Radiofrequency oscillators.

The two main classifications of oscillators are Harmonic or linear oscillators and Relaxation or non-linear oscillators. They are used in Clock generators, Calculators, other complex peripherals, and so on.

1). What is the very first practical oscillator based on?
Hint Electric arcs were utilized for lighting
2). Oscillator circuit built by _______________.
HintOscillator circuit in the year 1892
3). Parametric oscillator circuit is developed by ________.
HintGeorge Francis FitzGerald realized if the resistance in the resonance circuit is either made to zero or else negative
4). Arc oscillator rediscovered by _____________.
HintWilliam Duddell made popular the rediscovered Arc oscillator
5). Vacuum-tube Feedback Oscillators were invented in ___________.
HintAudion an electronic amplifying or detecting vacuum tube
6). Edwin Armstrong preferred ______________feedback.
HintRegenerative receivers
7). _______________ converts Direct Current (DC) signals available from the power supply units to Alternate Current (AC) signals.
HintOscillator accepts DC voltages and generates periodic waveform
8). A _________ criterion determines mathematical condition to obtain sustained oscillations.
HintBarkhausen criterion determines
9). What are the types of oscillators based on frequency as the parameter?
HintLFO and HFO
10). The _____________ feedback is used in oscillators.
HintPositive feedback gives the highest gain
11). Which of the oscillators doesn’t come under the category of low frequency oscillators?
HintCrystal oscillators operate at high frequencies
12). Both negative and the positive feedback is present in _______ oscillator.
HintTwo transistors are present in Wien bridge oscillators
13). The filter in the RC oscillator circuit consists of ___________.
HintLow-frequency oscillators
14). Which of these oscillators doesn’t consists of LC tank circuit?
HintWien bridge oscillator consists of resistors and capacitors
15). Positive feedback results in ___________ oscillations.
HintOscillations with constant amplitude and time
16) .Microprocessors uses _________ oscillators.
HintProcessing of high-speed data
17). UJT is a ____________ oscillator.
HintUJT produces non-sinusoidal waveform
18). The very first and the mostly used circuit of Relaxation oscillator is __________.
HintAstable multivibrator was discovered by French Engineers
19). __________ Circuits are the base for the design of contemporary microwave oscillators.
HintK. Kurokawa is the person to determine
20). Multivibrators comes under the category of ___________ oscillators.
HintMultivibrators produces square wave as the output
21). Non-sinusoidal oscillators are _____________.
HintRelaxation oscillator
22). The frequency in the LC oscillator is ____________.
HintHigher frequencies
23). Which is the most stable oscillator?
HintStable frequencies can be generated using Crystal oscillators
24). If the value of capacitor is at maximum in LC tank circuit, the energy at the inductor is ____________.
HintCapacitor and the energy at the inductor are inversely proportional
25). Hartley oscillator consists of ________ inductors.
HintTwo inductors are connected in series and parallel

Oscillator MCQs for Interview

26). The phase shift obtained at the feedbacks loop is ____________ degrees.
HintSustained oscillations
27). Theoretically the gain in the oscillator must be equal to _______.
HintGain must be slightly greater than 1
28). Which oscillator used to generate 1 Mega hertz signal?
HintLC circuit
29). Which oscillators are preferred in the Timing elements?
HintOscillators have the highest stability of frequency
30). Hartley oscillator has ________ capacitors in its Tank circuit.
HintOne capacitor and two inductors
31). Operating range of frequency of Hartley oscillators is _____________.
HintRealized by using Op-amps, FET, or BJT.
32). How many capacitors are present in Colpitts oscillator?
HintTwo capacitors are in series
33). Additional capacitor in series with the inductor is placed in which oscillator?
HintFrequency stability
34). The flow of energy is unidirectional in which oscillators?
HintHarmonic oscillators possess a unidirectional flow of energy
35). In which oscillators the energy can be exchanged between passive and the active components?
HintRelaxation oscillators are capable of exchanging the flow of energy
36). The oscillations frequency in harmonic oscillator can be determined by ______________.
HintHarmonic oscillators are also known as Feedback oscillators
37). Oscillations frequency of relaxation oscillators can be determined by ___________.
HintOscillation frequency depends upon the charging and discharging
38). Harmonic oscillators generate _______ waveforms as output.
HintLow-distorted sinusoidal waveforms
39). Relaxation oscillators generate _______ waveforms as output.
HintNon-sinusoidal signals
40). The device active in the LC oscillator of transistor is _________.
HintTransistor in the oscillator
41). The drawback of LC oscillators are _____________.
HintRC oscillators
42). Inductors used in LC oscillators makes the circuit bulky and ____________.
HintExpensive due to inductors
43). RC oscillators are also known as __________________
HintOutput sine signal generated is based on the phase shift
44). Total phase shift in the RC oscillators is _______.
HintEach section of RC produces 60 degrees
45). The frequency in the Phase shift oscillators can be determined by __________ components.
HintResistors and capacitors present to determine the frequency
46). Which oscillators has fixed set of frequencies?
HintHybrid clock
47). What is the reason of failure of Crystal oscillators?
HintCrystal oscillators consist of materials made of Piezo
48). The Q factor of the Crystal oscillator is ____________.
HintUnder damped
49). The network of RC in the Wien bridge oscillators is known as ___________.
HintPhase-shift present in the network
50). The increase in the frequency makes the phase-shift ____________ in the Wien bridge oscillator.
HintIncreased frequency

Oscillator Multiple Choice Question and Answers

51). The decrease in the frequency makes the phase-shift ___________ in the Wien bridge oscillator.
HintPhase shift tends to lead
52). How many RC networks present in Twin-T oscillators?
HintTwo RC networks
53). Feedback in the colpitts oscillator is by __________ component.
HintVoltage divider in the LC circuit
54). Tank circuits in Colpitts oscillator possess ________ capacitors.
HintTwo capacitors present in the LC circuit
55). Improved performance of Colpitts oscillator in comparison to the Hartley oscillator is because of _________ components.
HintCapacitive elements in the Colpitts oscillator
56). Gain device of Colpitts oscillators behaves as _______ filter.
HintOscillation frequencies are limited to certain ranges
57). Which feedback is present in Colpitts oscillator?
Hint To satisfy the Barkhausen condition
58). What is the active element of the Colpitts oscillator?
HintAmplify the weak signals transistor is used
59). The circuit of Colpitts oscillator is capacitive and improves the __________.
HintFrequency stability
60). Oscillations classified as sustained and damped based on ___________.
HintVariations in amplitude
61). Colpitts oscillator’s frequency is ________.
HintCt determines the equivalence capacitance
62). For the feedback component used in Hartley oscillators are _____________.
HintInductors in the Hartley oscillators
63). Number of capacitors in Hartley oscillator is _______.
HintHartley oscillator consists of one capacitor
64). Number of inductors in Hartley oscillators are _________.
HintTwo inductors are present in the Hartley oscillator's
65). Difference between Hartley and the Colpitts oscillators is _________.
HintFeedback
66). Self-limiting oscillators are ___________.
HintTank circuit
67). The voltage divided in the Clapps oscillator is due to _________.
HintModified version of the Colpitts oscillators
68). Which effect is present in Crystal oscillators?
HintPiezo
69). Threshold voltage is pre-determined in ______________.
HintCapacitors present in Relaxation oscillators
70). Relaxation oscillator made up of op-amp circuit is referred to as ____________.
HintAstable multivibrator possesses two states
71). Relaxation oscillator’s op-amp circuit generates ________ signal.
HintSignal undergoes a transition between two states
72). Possibility of signaling of internal clock in the digital circuits is by ____________.
HintFor internal signaling of clocks in the circuits relaxation oscillators are used
73). VCO stands for ________________.
HintThe applied value of the voltage at the input is determined by the frequency of oscillations in the voltage-controlled oscillators.
74). The frequency of oscillations in the VCO is controlled by __________.
HintInput voltage controls the frequency of oscillations
75). Phase-shift at the tank circuit of Hartley oscillators is ____________ degrees.
HintMeet the Barkhausen criteria

Oscillators Important Questions with Answers

76). An LC circuit in the oscillator is known as ____________.
HintInductor represented as L and the capacitor represented as C
77). RFC stands for ______________.
HintRadiofrequency choke at the collector provides higher reactance
78). Clapp Oscillator preferred above __________ for the construction of Variable frequency oscillators.
HintTuning circuits present at receivers
79). How many capacitors are present in the Clapp oscillators?
HintVoltage divider circuit in the Clapp oscillator
80). Which type of feedback is present in Clapp oscillators?
Hint Positive feedback is preferred
81). The amount or the value of the feedback applied as the input at transistor is determined by ________ in the Clapp oscillators.
HintVoltage divider circuit formed with three capacitors
82). _____________ oscillator has the constant frequency in the output.
HintCrystal oscillator's main feature is the constant frequency
83). If there is no signal at input applied what triggers the operation of oscillators?
HintPresence of noise voltage
84). Harmonic oscillators are ________.
HintGenerates sinusoidal waves
85).Which of these is not considered as non-sinusoidal oscillators?
HintSinusoidal oscillators
86). If the value of capacitor is tends to be maximum the energy at the inductor reaches ___________ in LC oscillators.
HintCapacitor value and the inductor energy are inversely proportional
87). If the frequency of the crystal tends to change with temperature, the crystal is said to have __________ coefficient of temperature.
HintElectrical resistance increases with the increase in temperature
88). Basic difference between oscillators and amplifiers is ___________.
HintWithout the application of input
89). What is the limitation of Crystal oscillator?
HintLow output is the main limitation
90). Ocxo is an acronym for ___________.
Hint The top-performing quartz Crystal oscillator
91). Which oscillator is known as Meissner oscillator?
HintArmstrong oscillator is an electronic oscillator
92). __________ oscillators have transformer coupling.
HintArmstrong oscillators are less popular
93). Practically a circuit for triangular-wave is a combination of __________.
HintTriangular wave generators use fast comparators
94). __________ oscillators frequency gets varied by varying DC control voltage.
Hint Integrator used in VCO
95). Crystal oscillators are mostly found in ___________.
HintRadio transmitters
96). A GPS unit uses __________ oscillators.
HintPhase-shift oscillators utilized where the extensive frequency ranges
97). Radio receivers use ___________ oscillators.
HintHartley oscillators are used for operating at radio frequencies
98). Phase-Locked loop (PLL) uses ________ oscillators.
Hint The output signal in PLL
99). Digital systems prefer _____________ oscillators.
HintThe precise and highest stability in frequency obtained by using Crystal oscillators
100). The signal generators utilized in the general laboratories are _______ oscillators.
HintWithout input, Wien bridge oscillators produce continuous oscillations of output
101). 555 Timer consists of ________.
Hint555 Timer consists of two comparators, a flip-flop, a discharge transistor
102). The crystal in crystal oscillator acts as __________.
HintResonant circuit

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