Question

What is the difference between a voltage follower and a buffer amplifier?

Answer 1

A voltage follower and a buffer amplifier essentially refer to the same type of circuit, but the terminology might be used in different contexts. Here’s a breakdown:

Voltage Follower:

1. A voltage follower is a specific type of op-amp circuit where the output voltage exactly follows the input voltage.
   

1. Its main purpose is to isolate the input and output, meaning it does not draw significant current from the input and thus prevents the circuit connected to the input from being affected by the load.
   

1. The voltage gain is 1 (or unity), meaning the output voltage is equal to the input voltage.
   

1. It is used to prevent signal loss or interference and provide high input impedance and low output impedance.
   

Buffer Amplifier:

1. A buffer amplifier is a more general term used for any amplifier that isolates its input from its output.
   

1. Like a voltage follower, a buffer amplifier typically has a unity gain (gain of 1), but the term "buffer" can refer to any amplifier used to "buffer" or isolate stages in a circuit.
   

1. The term buffer amplifier is often used in a broader range of applications, not limited to just op-amps.
   

Key Points of Difference:

1. Terminology: A voltage follower is a specific type of buffer amplifier, typically using an op-amp. The term buffer amplifier can apply to various amplifier types (not necessarily limited to voltage followers).
   

1. Purpose: Both serve to isolate and prevent loading effects between different stages of a circuit, but "buffer" may imply broader usage.
   

In simple terms, a voltage follower is a buffer amplifier with specific characteristics (using an op-amp and unity gain). So, you can think of all voltage followers as buffer amplifiers, but not all buffer amplifiers are voltage followers.