What is meaning of the switching transistor?
Switching transistor : When a transistor is used as switch, it is called as switching transistor.
Give reason: The transistor has high efficiency as a switch in the OFF
and Saturation condition.
Transistor OFF state
The collector leakage current flow through transistor during its OFF state therefore the power loss is small as compared to full load current. Due to this reason its efficiency is high during OFF state.
Transistor saturation state
The
power loss during saturation condition is quite low because of small knee
voltage.
At which state the transistor operates like switch?
Transistor as switch
Cut off
The transistor operates like an open circuit.
Saturation
The
transistor operates like short circuit. Therefore, the transistor operates like
switch in the cut off and saturation region.
Which is stable region for operation of the transistor?
Active
region
What is meaning of the multi - vibrator?
Multi – vibrator : It is an electronic circuit which generates non – sinusoidal waveforms.
Which type of feedback is used in the multi – vibrator circuit?
Positive
feedback
How many stages the multi – vibrator consists of?
The
multi – vibrator circuit consists of two stage amplifiers in which output of
the one amplifier feedback to the input of the other amplifier.
Which type of waveform the output of the multi – vibrator consists of?
The
output of the multi – vibrator should be square or rectangular waveform which
depends upon circuit conditions.
Describe the different types of multi – vibrator.
Types of multi – vibrator
Astable
(Free running)
Monostable
(One shot)
Bi
– stable (Two shot or flip flop)
Explain the term: Astable multi – vibrator
Astable multi – vibrator
It
is multi – vibrator in which the operation of two states changes automatically.
However, the time of operation of a state depends upon circuit parameters. It
is also called as free running multi – vibrator.
Explain the term: Monostable multi – vibrator
Mono stable multi – vibrator
It
is multi – vibrator which has one stable state and quasi stable i.e., half
stable. One transistor is in ON state whereas the other transistor is in OFF
state. When the input pulse is applied the circuit changes its state. It is
also called as one shot multi – vibrator.
Explain the term: Bi – stable multi – vibrator
Bi – stable multi – vibrator
It
is multi – vibrator which has two stable states. One pulse is used to generate
half cycle of the square wave and another pulse is used to generate next half
cycle of the square wave.
Which multi – vibrator generates square wave without any external pulse?
Astable
or free running multi – vibrator
Which multi – vibrator has no stable state?
Astable
or free running multi – vibrator
Write the expression of frequency for the square wave Astable multi –
vibrator
Frequency
of square wave = 1 / T
Where T = 1.4RC
Which multi – vibrator has only one stable state?
Monostable
multi – vibrator
Which multi – vibrator has two stable states?
Bistable
multi – vibrator
Describe the function of feedback capacitors in the Bistable multi –
vibrator.
Function of feedback capacitors
To
improve the switching characteristics
To produce distortion less square wave output
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