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]

Potentiometer

 
Potentiometer

What is a potentiometer? A potentiometer is a manually adjustable variable resistor with 3 terminals. Two terminals are connected to both ends of a resistive element, and the third terminal connects to a sliding contact, called a wiper, moving over the resistive element. The position of the wiper determines the output voltage of the potentiometer. The potentiometer essentially functions as a variable voltage divider. The resistive element can be seen as two resistors in series(potentiometer resistance), where the wiper position determines the resistance ratio of the first resistor to the second resistor. A potentiometer is also commonly known as a potmeter or pot. The most common form of potmeter is the single turn rotary potmeter. This type of pot is often used in audio volume control (logarithmic taper) as well as many other applications. Different materials are used to construct potentiometers, including carbon composition, cermet, wirewound, conductive plastic or metal film. Potentiometer definition A potentiometer is a manually adjustable, variable resistor with three terminals. Two terminals are connected to a resistive element, the third terminal is connected to an adjustable wiper. The position of the wiper determines the output voltage. Types of potentiometers A wide variety of potmeters exist. Manually adjustable potmeters can be divided in rotary or linear movement types. The tables below list the available types and their applications. Besides manually adjustable pots, also electronically controlled potentiometers exist, often called digital potmeters. Rotary potentiometers The most common type of potentiometer where the wiper moves along a circular path. Type Description Applications Single-turn pot Single rotation of approximately 270 degrees or 3/4 of a full turn Most common pot, used in applications where a single turn provides enough control resolution. Multi-turn pot Multiple rotations (mostly 5, 10 or 20), for increased precision. They are constructed either with a wiper [... read more]