Question

1. Explain what is the function of Op amplifier?
2. What is the function of voltage follower?

Answer 1

An Operational Amplifier or op-amp is a voltage amplifying device designed to be used with external feedback components such as resistors and capacitors between its output and input terminals. It is a high-gain electronic voltage amplifier with a differential input and usually a single-ended output. These feedback components determine the resulting function or “operation” of the amplifier and by virtue of the different feedback configurations whether resistive, capacitive or both, the amplifier can perform a variety of different operations, giving rise to its name of “Operational Amplifier”.

A voltage follower (also called a unity-gain amplifier, a buffer amplifier, and an isolation amplifier) is an op-amp circuit which has a voltage gain of 1.

This means that the op-amp does not provide any amplification to the signal. The reason it is called a voltage follower is that the output voltage directly follows the input voltage, meaning the output voltage is the same as the input voltage.

Whenever we are sending a voltage signal from one subcircuit to another, we have to consider the output impedance of the source subcircuit and the input impedance of the load subcircuit. The source’s output impedance and the load’s input impedance form a voltage divider, and consequently, voltage transfer depends on the ratio of input impedance to output impedance. Effective voltage-transfer requires a source circuit with low output impedance and a load circuit with high input impedance.

A voltage follower has low output impedance and extremely high input impedance, and this makes it a simple and effective solution to problematic impedance relationships. If a high-output-impedance subcircuit must transfer a signal to a low-input-impedance subcircuit, a voltage follower placed between these two subcircuits will ensure that the full voltage is delivered to the load.