User Manual

Nomenclature
There are a number of terms in the electronics industry used to describe certain types of
potentiometers:
 slide pot or slider pot: a potentiometer that is adjusted by sliding the wiper left or right (or up
and down, depending on the installation), usually with a finger or thumb
 thumb pot or thumbwheel pot: a small rotating potentiometer meant to be adjusted
infrequently by means of a small thumbwheel
 trimpot or trimmer pot: a trimmer potentiometer typically meant to be adjusted once or
infrequently for "fine-tuning" an electrical signal
Potentiometer construction
Single-turn potentiometer with metal casing removed to expose wiper contacts and resistive track
Potentiometers comprise a resistive element, a sliding contact (wiper) that moves along the element,
making good electrical contact with one part of it, electrical terminals at each end of the element, a
mechanism that moves the wiper from one end to the other, and a housing containing the element
and wiper.
Many inexpensive potentiometers are constructed with a resistive element formed into an arc of a
circle usually a little less than a full turn and a wiper sliding on this element when rotated, making
electrical contact. The resistive element, with a terminal at each end, is flat or angled. The wiper is
connected to a third terminal, usually between the other two. On panel potentiometers, the wiper is
usually the center terminal of three. For single-turn potentiometers, this wiper typically travels just
under one revolution around the contact. The only point of ingress for contamination is the narrow
space between the shaft and the housing it rotates in.
Another type is the linear slider potentiometer, which has a wiper which slides along a linear element
instead of rotating. Contamination can potentially enter anywhere along the slot the slider moves in,
making effective sealing more difficult and compromising long-term reliability. An advantage of the
slider potentiometer is that the slider position gives a visual indication of its setting. While the setting
of a rotary potentiometer can be seen by the position of a marking on the knob, an array of sliders
can give a visual impression of, for example, the effect of a multi-band equaliser (hence the term
"graphic equaliser").
The resistive element of inexpensive potentiometers is often made of graphite. Other materials used
include resistance wire, carbon particles in plastic, and a ceramic/metal mixture called cermet.
Conductive track potentiometers use conductive polymer resistor pastes that contain hard-wearing
resins and polymers, solvents, and lubricant, in addition to the carbon that provides the conductive
properties.