8 Voltage Follower
Figure 8-1 displays an op amp in voltage follower configuration, also known as a unity-gain buffer or voltage buffer. The non-inverting (+) input is connected to a pin, and the output is connected to the inverting (-) input.
The output voltage is equal to the input voltage, giving the transfer function:
The configuration does not provide any amplification thus the voltage gain is equal to
1.
The voltage follower is mainly used for converting a high input impedance to a low output impedance. It is often found in the sample and hold circuits as an input to analog to digital converters (ADC) or buffers for logic circuits.