Potentiometer Resistance Taper

Potentiometer Resistance Taper

Potentiometers come with a resistance taper- either linear or log.

This specifies how a resistance changes in value as the wiper of the potentiometer is turned. Resistance will either change linearly or logarithmically.

Linear Tapers

Linear Taper Potentiometers are potentiometers that change resistance in a linear fashion as you turn the wiper. For example, a 20% turn in the potentiometer will change the resistance 20%. It's a perfectly direct relationship, as you can see in the diagram below.

Linear taper potentiometers are the most common type of potentiometers and are used in most applications when potentiometers are used, except for audio.

Log Tapers

Log Tapers are potentiometers that change resistance logarithmically as you turn the wiper. You can see the curve on the diagram below.

The main and most common use of a log taper potentiometer is for use in audio. Ours ears perceive sound in a logarithmic fashion. If you were to use a linear potentiometer for volume control, increasing and decreasing sound, the volume changes would not turn out right. A linear taper's adjustment grows far too rapidly as the pot is turned up from zero. This means that the volume levels shoot up too high right when you beginning turning it up. Volume control then is very difficult. For linear tapers, the volume control is squeezed into the first 60 degrees or so of rotation, while the rest of the rotation has little effect of audio. Linear tapers are just not built to manage audio. Log tapers, though, are perfect for audio applications. Its characteristics are suitable to the way our ears receive increasing or decreasing sounds. It gradually increases sound as the wiper is turned.

Characteristics Curves

The characteristic curves for linear and log tapers are shown below:

Potentiometer Resistance Taper Characteristics Curves

You can see the direct relationship that linear tapers have, while you see the parabolic relationship that log tapers have.

Related Resources

Linear Taper Potentiometers

Log Taper Potentiometers

Audio Taper Potentiometers

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