Question

A basic generalized form of comparator is:
(A) Zero- Crossing Detector
(B) Sine to Square Wave Generator
(C) Both A and B
(D) None of the above

Answer 1

We should know that a square wave is a non-sinusoidal periodic waveform in which the amplitude alternates at a steady frequency between fixed minimum and maximum values, with the same duration at minimum and maximum. In an ideal square wave, the transitions between minimum and maximum are instantaneous. On the other hand, a sine wave or sinusoid is a mathematical curve that describes a smooth periodic oscillation. A sine wave is a continuous wave. It is named after the function sine, of which it is the graph. It occurs often in both pure and applied mathematics, as well as physics, engineering, signal processing and many other fields. On the basis of this concept we have to write this answer.

Complete step by step answer
We should know that a comparator is a device that compares two voltages or currents and outputs a digital signal indicating which is larger. It has two analog input terminals and one binary digital output. The output is ideally accepted. A comparator circuit compares two voltages and outputs either a 1 (the voltage at the plus side, VDD in the illustration) or a 0 (the voltage at the negative side) to indicate which is larger. Comparators are often used, for example, to check whether an input has reached some predetermined value.
The comparator can be configured to be useful in the form of Zero Crossing Detector by just adjusting reference voltage to zero. There is sometimes a possibility that low frequency signals may consume some more time to cross zero volt because of which output voltage cannot switch over instantaneously from one saturation region to another.
Also, the noise at the op-amp input terminals may fluctuate the output between positive $(+{{V}_{sat}},-{{V}_{sat}})$ and negative saturation voltages. Hence, both the shortcomings can be resolved by using positive or (regenerative) feedback. In such a condition, a square wave generator is used.

Hence, option C is correct.

Note: We should know that a zero-crossing detector or ZCD is one type of voltage comparator, used to detect a sine waveform transition from positive and negative, that coincides when the i/p crosses the zero-voltage condition. Zero-crossing detectors are used to synchronize switching with the AC wavelength or to extract the timing signal. By using zero crossing techniques, high inrush currents can be avoided. A zero-crossing detector is a comparator with the reference level set at zero. It is used for detecting the zero crossings of AC signals.
It should also be known as the square wave generator is defined as an oscillator that gives the output without any input, without any input in the sense we should give input within zero seconds that means it must be an impulse input. This generator is used in digital signal processing and electronic applications. Square waves are used to control the timing of operations in digital systems, such as clock generators for microprocessors. They also have many uses in analogue circuits from simple lamp flashers to complex control systems as well as pulse width control systems for audio and radio applications.