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WorksheetsLarge signal Amplifier
Total questions: 20
Worksheet time: 10mins
A power Amplifier in which the transistor is ON for full cycle (360 degree) of a signal input is
Class A
Class B
Class C
Class AB
The Class A amplifie has
high efficiency and high distortion
loe efficiency and high distortion
low efficiency and low distortion
low efficiency and low distotion
In Class A amplifier , the worst case distottion occurs with
transformer coupling
maximum input signal
high load resistance
zero signal input
The ratio of signal power delivered to load to dc power supplied to the amplifier is
gain factor
Loss factor
converison factor
none of these
When compared to Class B amplifier, Class A power amplifer
has more efficiency
has less distortions
is not susceptable to power supply hum
has less efficency,less distortions and susceptable to power supply hum
If a transistor audio amplifieris found to have over all efficiency of 70% it is called
Class B push pull amplifier
Single stage Class C amplifier
transformer coupled Class a amplifier
direct coupled Class A amplifer
The output of a Clas B amplifier
consist of positive half cycle
is distortion free
is like the output of fule wave rectifier
comprises of short duration current pulses
The amplifier that suffers mainly from the problem of cross over distortion is
Class A
Class B
Class AB
Class C
A push pull amplifier
reduces even harmonics in the output
is the first stage of audio amplifier
reduces odd harmonics in the output
uses single transistor
Heat sinks are used with power amplifier
reduce harmonics in the output
increase the collector discipation rating of the transistor
increase the output power
reduce the heat losses in the transistor
In Class A conduction extends 360 degreebecause Q-point is
is located at the load line
located at or near cutt off points
located near saturation points
reduces the heat losses in the transistor
Consider the following statements: A ClassBb amplifer
1.is biased just at cutt off
2.has high therotical efficiencyof 78.55becuse its quscient current is low
3.is biased at mid-point of load line
2 and 3 are correct
1 alone is correct
2 alone is correct
1 and 2 are correct
In Class C amplifier
efficiency and distortions both are maximum
efficiency is minimum but distortion is maximum
efficiency is maximum but distortion is minimum
In a transistor push-pull amplifer
there is no dc present in the output
there is no distortion in the outputn
there are no even harmonics in the output
there are no odd harmonics in the output
What is the main source of distortions in a push pull amplifier
fundamental component
Second harmonics
Third harmonic
All even harmonics
Class AB operation is often used in power amplifier inorder to
get maximum efficiency
remove even harmonics
cross over distortions
reduce collector dissipation
Consider the following staements regarding Class b amplifier (complementry symmetry type)
1.The efficency of the amplifier is higher than that of Class A amplifier
2. The poweroutpt is low
3.Cross over distortion is present
4. The stand by power dissipation is absent
which of the follwing statement is correct ?
1,2,3
1,2,4
1,3,4
2,3,4
In case od Class A amplifer ,the ratio (efficiency of tranformer coupled /efficiency of transformer less amplifier) is
2.9
1.36
1
0.5
A Class A transformer coupled , transistor power amplifier is recquired to deliver a power outputof 10 watts. The maximumpower ratingof the transistor should not be less than
5W
10 W
20W
40W
Crossover distortions behavious is a charecteristics of
Class A output stage
Class AB output stage
Class B output stage
Common base outptut stage
