Question

In which of the following are operational amplifiers (op-amps) used?
A. Oscillators
B. Filters
C. Instrumentation circuits
D. All of the above

Answer 1

Hint: In this question we have to use the knowledge of operational amplifiers and the fields of usage of it. We have to consider the options and then see which of the fields id operational amplifiers used.

Complete step by step answer:
For finding if the operational amplifiers are used in any of the options, first let’s discuss some points of operational amplifiers.
An operational amplifier is a solid-state device which is capable of sensing and amplifying direct current and alternating current signals. It is an Amplifier which takes two inputs (differential inputs) and a single output. The two differential inputs are the positive and negative power supply Often known as dual power supply. Op-amp allows the output voltage to vary positive and negative with respect to ground. It has a very high input impedance and produces negligible current at the inputs.
It also has a very high gain. The output impedance of the amplifier is also very low and it does not affect the output of the amplifier by loading.
If we consider the first option that is the Oscillators, there is a need of phase shift so as to produce oscillations, for this a negative gain operational amplifier and a three section RC network is used. The connection of the phase shift network from the operational amplifier is done back to inverting input.
Hence, the op-amps are used in Oscillators.
Considering the second options, the Filters. In Filters there is a need for active components. Here the Operational amplifier is used as active components. Hence, OP-amps is also used in Filters.
Now the third option i.e. Instrumentation circuits, in such circuits Instrumentation amplifiers is a type of
differential amplifiers which have been outfitted with input buffers amplifiers. Hence here also the operational amplifiers are used.

So, the correct answer is “Option D”.

Note:
for attempting questions like these properties of circuits like operational amplifiers is very important. Students should know which property is utilized in which field and then only one will be able to answer such questions.