A voltage follower, also known as a buffer circuit, is an electronic circuit that has an input and an output, and it is designed to have a unity voltage gain (gain of 1). This means that the output voltage of the buffer circuit mirrors the input voltage exactly, without amplifying or attenuating it. In other words, the output voltage "follows" the input voltage.
The primary purpose of a voltage follower circuit is to isolate or decouple the input signal from the load or subsequent stages in a larger circuit. It provides impedance matching and prevents the loading effect, where the input signal might be weakened due to the impedance of the connected load.
Here are a few key points about the use and benefits of voltage follower circuits:
Impedance Matching: When connecting two different parts of a circuit with different input and output impedance, a voltage follower can help match these impedances and prevent signal degradation. This is particularly important when driving sensitive components that might be affected by changes in input impedance.
Isolation and Loading: A voltage follower acts as a buffer between the input and the load, preventing the load from affecting the original input signal. This is especially useful when the load impedance is significantly lower than the output impedance of the signal source, as it prevents distortion or attenuation of the signal.
Signal Conditioning: In some cases, a voltage follower can provide signal conditioning by offering a high input impedance and low output impedance. This can help maintain signal integrity and reduce the impact of noise or interference on the signal.
Voltage Level Shifting: Voltage followers can also be used for level shifting purposes. If you need to shift a signal from one voltage level to another while maintaining the same waveform shape, a voltage follower can be employed.
Feedback Circuits: Voltage followers are often used as part of feedback circuits in operational amplifier (op-amp) applications. They can help control gain and stabilize the circuit's performance.
The most common type of voltage follower is implemented using an operational amplifier (op-amp) with a unity gain configuration. Op-amps are widely used in voltage follower circuits due to their high input impedance, low output impedance, and ability to provide accurate unity gain.
In summary, a voltage follower (buffer) circuit is a simple yet essential component in electronic circuits, helping to maintain signal integrity, prevent loading effects, and match impedance between different stages of a circuit.