Potentiometer taper

 
Potentiometer taper

What is potentiometer taper? Potentiometer taper is the relation between the position and the resistance of a pot. In the majority of variable resistors available this is a linear relationship, meaning that the relative position is equal to the resistance ratio. For example when the potmeter is at the middle position, the output voltage is half of the full voltage over the potentiometer. For some applications and especially audio volume control, non-linear, logarithmic tapers are used. Definition Taper is the relation between the position of the potentiometer and the resistance ratio. Types The simple linear taper is the most common form, when we plot the position against the resistance ratio we can visualize the different position-resistance relations. The graph below shows the most used tapers. The first and last few percents of travel are often only mechanical with no change in resistance. The region between 5 and 95% where the electrical resistance changes is called the electrical travel. The available travel for rotary pots is often denoted in degrees, a mechanical travel of 300° combined with a electrical travel of 270° is common. Audio taper The most used non-linear taper is the logarithmic (log) or audio taper. This is mainly used for audio volume control, to obtain a more natural ‘linear’ perception in sound intensity change when you adjust the volume. Because the human ear is sensitive to sound intensity in a logarithmic fashion, at low sound intensities a small change in intensity is perceived as a big change in loudness, while at high intensities a large change is required for the same change in perceived loudness. To compensate for the ears logarithmic behavior, audio taper pots were developed. While it is called logarithmic, it is actually an exponential curve (the opposite of the logarithmic behavior of the human ear). [… read more]