Question

What are the diodes(D1 &D2) used in a comparator circuit ?
A) Clip diodes
B) Clamp diodes
C) PIN diodes
D) Fast recovery diode

Answer 1

Hint:For finding the type of diodes, we will define the comparator circuit first and its working.
Then we will find the function which diodes perform in the comparator circuit, after that we can easily make out the diodes used in the comparator circuit.

Complete step by step solution:
Comparator circuit: The comparator is an electronic decision making circuit that makes use of an operational amplifier having very high gain in its open-loop state, that is there will be no feedback resistor.

The comparator compares a signal voltage on one input of an op amp with a known reference voltage on the other input. Comparator usually has two inputs, one is constant reference voltage and the other is a time varying voltage signal .

When the non inverting input is larger than the inverting voltage the comparator produces a high output voltage +Saturation. When the non-inverting input is less than the inverting input the output voltage will –Vsaturation .

          

The above circuit diagram shows the diodes D1 and D2 .These two diodes are used to protect the op-amp from damage due to increase in input voltage. These diodes are called clamp diodes because they clamp the differential input voltage to either 0.7V or -0.7V .

Thus option 2 is correct.

Note:Most useful application of a comparator circuit is a humidity monitoring system of soil based on wireless sensor networks. The system is designed for developing an automatic irrigation system that can control the switching operation of the pump motor depending upon the moisture content in the soil.