Function of op-amp Configurations

Basic Understanding of Op-Amps

An op-amp, or operational amplifier, is typically a high-gain electronic voltage amplifier with differential input and, typically, a single-ended output.
The basic function of an op-amp is to amplify the differential input voltage while rejecting noise signals that are the same on both inputs.
An op-amp can be used in a variety of ways in electronics and control systems. The output voltage waveform from the op-amp is directly proportional to the input voltage waveform.

Different Op-Amp Configurations

Inverting amplifier: The output is an inverted and amplified version of the input signal. It’s often used in audio amplifiers and signal processing circuits.
Non-inverting amplifier: In this setup, the output is a non-inverted (i.e., it preserves the input signal’s phase) and amplified version of the input signal.
Summing amplifier: This takes multiple input signals and combines them into a single output signal. It is the electronic equivalent of an electrical circuit’s ‘summing point’.
Differential amplifier: A differential amplifier magnifies the difference between two inputs and is important in eliminating ‘noise’ that may appear across both inputs from an output signal.
Voltage follower or Buffer amplifier: This configuration produces an output signal identical to the input. It’s ideal for isolating stages from each other in a circuit or providing a high impedance input.
Integrator amplifier: This configuration can integrate the input signal over time. Uses of integrator amplifiers include analog computing, ramp generators and waveform generators.
Differentiator Amplifier: This type of op-amp produces an output that is proportional to the rate of change of the applied input. Differentiator amplifiers are used for wave shaping and frequency modulations.

Key Points for Op-Amp Configuration

Each configuration serves a different purpose and will be used in different parts of a system depending on what needs to be achieved.
Different configurations will result in different output signals from the op-amp.
Op-amp configurations can be ‘mixed and matched’ within a system to get the desired output.
Whatever the configuration, the gain of an op-amp is very high. However, in practice, this gain is often reduced and controlled by using negative feedback.
Operating parameters of op-amps such as input and output impedances, gain, bandwidth, and power supply rejection ratio can all change, depending on the configuration it is used in.

Practising design and evaluation of different op-amp configurations can aid in understanding how different configurations affect the amplified output. It also helps understand how op-amps can be used in a variety of applications throughout analogue controller designs.