spänningsfollower

A spänningsfollower, also known as a voltage follower or unity gain buffer, is a type of buffer amplifier where the output voltage is equal to the input voltage. It has a voltage gain of one, hence the name "unity gain." This circuit is typically constructed using an operational amplifier (op-amp).

The primary function of a spänningsfollower is to provide impedance transformation. It presents a very high input impedance to the source signal, drawing minimal current from it. Simultaneously, it offers a very low output impedance, allowing it to drive loads that would otherwise be difficult for the original source to handle without significant signal degradation.

In a typical op-amp configuration, the output of the op-amp is directly connected to its inverting input. The input signal is applied to the non-inverting input. The op-amp's high open-loop gain, combined with this feedback arrangement, forces the output voltage to closely match the input voltage.

Spänningsfollowers are widely used in electronic circuits to isolate different stages, buffer sensor outputs, and interface high-impedance sources with low-impedance loads. They are essential for preventing loading effects that can alter the signal being measured or processed. While the voltage gain is unity, the current gain is very high, making it an effective power buffer.