1. Monostable multivibrator may be used to generate
A monostable multivibrator may be used to generate pulses whereas an Astable multivibrator may be used to generate a square wave.
2. A 1 μs pulse can be converted into a 1 ms pulse by using
A monostable multivibrator
An astable multivibrator
A bistable multivibrator
A J – K flip-flop
Answer.1. A monostable multivibrator
Given that the 1 μs pulse is converted into a 1 ms.
This is pulse widening. This can be achieved with the help of the monostable multivibrator.
3. The pulse width out of a one-shot multi-vibrator increases when the
Supply voltage increases
Timing resistor decreases
Timing capacitance increases
Answer.4. Timing capacitance increases
The pulse width of a one-shot multivibrator depends on the formula,
τ = 1.1 RTCT
Hence, the timing cycle of the monostable multivibrator is determined by the timing capacitor, CT, and the resistor RT until it resets or returns to the original state.
It remains in the original stable state indefinitely until another input pulse or trigger signal is received. Hence, it has only one stable state.
4. Which of the following is not the other name for the Monostable Multi-vibrator circuit?
Square wave generator
Answer.4. Square wave generator
Square wave generator:
It is defined as an oscillator that gives the output without any input.
This generator is used in digital signal processing and electronic applications.
The square wave generator is also known as an Astable multivibrator or free-running.
The frequency of the square wave generator is independent of the output voltage.
So, a square wave generator is an astable multivibrator and not monostable multivibrator.
5. Which among the following multivibrators is unstable in any state?
Both astable and bistable multivibrator
Answer.1. Astable multivibrator
An Astable multivibrator is such a circuit that it automatically switches between the two states continuously without the application of any external pulse for its operation, i.e. it is unstable in any state.
As this produces a continuous square wave output, it is called a free-running multivibrator.
6. The formula for the frequency of a 555 astable multivibrator
1.44/(RA + 2RB)C
(RA + 2RB)c/1.44
(RA + 2RB)C
None of the above
Answer.1. 1.44/(RA + 2RB)C
Time period high of 555 timers is given by
THigh = 0.693(RA + RB) C
Tlow = 0.693 RBC
Thus, total time period T is given by
T = THigh + Tlow
T = 0.693 (RA + 2 RB) C
f = 1/T = 1.44/(RA + 2RB)C
7. Schmitt trigger can be used as a
Square wave generator
All of these
Answer.4. All of these
A Schmitt trigger is basically an inverting comparator circuit with positive feedback.
The purpose of the Schmitt trigger is to convert any regular or irregular-shaped input waveform into a square wave output voltage or pulse.
Thus, it can also be called a squaring circuit and can be used as a square wave generator.
When the input is below a different (lower) chosen threshold, then the output is low, and when the input is between the two levels, the output retains its value.
This dual-threshold action is called hysteresis and implies that the Schmitt trigger possesses memory and can act as a bistable multivibrator (latch or flip-flop).
8. The bistable multivibrator
has two stable states
has one stable state
is free running
none of the above
Answer.1. has two stable states
A Bistable multivibrator has both the two states stable. It requires two trigger pulses to be applied to change the states. Until the trigger input is given, this multivibrator cannot change its state.
9. A monostable multivibrator is frequently used
in memory and timing circuits
for regeneration of distorted waves
in counting circuits
for producing triangular waves
Answer.2. for regeneration of distorted waves
The Monostable Multivibrator circuit has only ONE stable state making it a “one-shot” pulse generator
Monostable multivibrators can consider as triggered pulse generators
It is used as delay and timing circuits
It is used for the generation of clock pulse
It is used for the regeneration of distorted waves
It is also used in analog systems to control an output signal frequency
10. A monostable multivibrator requires
no driving pulse for generation of output cycles
one driving pulse for each output cycle
two driving pulses for each output cycle
four driving pulses for each output cycle
Answer.2. one driving pulse for each output cycle
A Monostable multivibrator has a stable state and a quasi-stable state. This has a trigger input to one transistor. So, one transistor changes its state automatically, while the other one needs a trigger input to change its state.