561.
Which is a fixed frequency oscillator
A
Phase-shift oscillator
B
Hartely-oscillator
C
Colpitts oscillator
D
Crystal oscillator
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Which is a fixed frequency oscillator
Phase-shift oscillator
Hartely-oscillator
Colpitts oscillator
Crystal oscillator
What percentage of feedback will cause oscillations?
0.20%
0.50%
1.50%
2%
The signal generator generally used in the laboratories is .............. oscillator
Wien-bridge
Hartely
Crystal
Phase shift
The Q of the crystal is of the order of
100
1000
50
More than 10,000
Quartz crystal is most commonly used in crystal oscillators because
It has superior electrical properties
It is easily available
It is quite inexpensive
None of the above
Oscillators must employ
Possitive feedback
Negative feedback
Neither negative nor positive feedbacks
None of the above
In Colpitts oscillator, feedback is obtained
By magnetic induction
By a tickler coil
From the centre of split capacitors
None of the above
In a phase shift oscillator, we use .............. RC sections
Two
Three
Four
None of the above
Hartley oscillator is commonly used in
Radio receivers
Radio transmitters
TV receivers
None of the above
For an oscillator to properly start, the gain around the feedback loop must initially be
1
Greater than 1
Less than 1
Equal to attenuation of feedback circuit
An oscillator produces .............. oscillations
Damped
Undamped
Modulated
None of the above
An oscillator employs .............. feedback
Positive
Negative
Neither positive nor negative
Data insufficient
An oscillator differs from an amplifier because it
Has more gain
Requires no input signal
Requires no d.supply
Always has the same input
An oscillator converts
power into d.power
power into a.power
mechanical power into a.power
none of the above
An LC oscillator cannot be used to produce .............. frequencies
High
Audio
Very low
Very high
A Wien bridge oscillator uses .............. feedback
Only positive
Only negative
Both positive and negative
None of the above
When a capacitor is used in place of a resistor in an op-amp network, its placement determines:
Open or closed-loop gain
Integration or differentiation
Saturation or cutoff
Addition or subtraction
The major difference between ground and virtual ground is that virtual ground is only a:
Voltage reference
Current reference
Power reference
Difference reference
If the input to a comparator is a sine wave, the output is a:
Ramp voltage
Sine wave
Rectangular wave
Sawtooth wave
The ratio between differential gain and common-mode gain is called:
Amplitude
Differential-mode rejection
Common-mode rejection
Phase