Multivibrator Interview Short Question

1	What is meaning of the switching transistor?
	Switching transistor When a transistor is used as switch, it is called as switching transistor.
2	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.
3	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.
4	Which is stable region for operation of the transistor?
	Active region
5	What is meaning of the multi - vibrator?
	Multi – vibrator It is an electronic circuit which generates non – sinusoidal waveform.
6	Which type of feedback is used in the multi – vibrator circuit?
	Positive feedback
7	How many stages the multi – vibrator consists of?
	The multi – vibrator circuit consists of two stage amplifier in which output of the one amplifier feedback to the input of the other amplifier.
8	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.
9	Describe the different types of multi – vibrator.
	Types of multi – vibrator Astable ( Free running ) Monostable ( One shot ) Bi – stable ( Two shot or flip flop )
10	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.
11	Which multi – vibrator generates square wave without any external pulse?
	Astable or free running multi – vibrator
12	Which multi – vibrator has no stable state?
	Astable or free running multi – vibrator
13	Write the expression of frequency for the square wave Astable multi – vibrator
	Frequency of square wave = 1 / T Where T = 1.4RC
14	Which multi – vibrator has only one stable state?
	Monostable multi – vibrator
15	Which multi – vibrator has two stable states?
	Bistable multi – vibrator
16	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