Resistance–position relationship: "taper", "Linear Type Precision Potentiometer Diagram", .PDF edition of Carl David Todd (ed), "The Potentiometer Handbook",McGraw Hill, New York 1975, Electrical calibration equipment including various measurement potentiometers, The Secret Life of Pots - Dissecting and repairing potentiometers, Potentiometer calculations as voltage divider - loaded and open circuit (unloaded), https://en.wikipedia.org/w/index.php?title=Potentiometer&oldid=984418110#Rheostat, Articles containing Ancient Greek (to 1453)-language text, Short description is different from Wikidata, Creative Commons Attribution-ShareAlike License, This page was last edited on 20 October 2020, at 00:38. 2 {\displaystyle R_{2}=2\ \mathrm {k\Omega } } A logarithmic taper potentiometer is a potentiometer that has a bias built into the resistive element. The resistors are passive components manufactured specifically to … 10 Ce terme de « rhéostat » est obsolescent[3], et tend à être remplacé par le terme plus général de « potentiomètre. Low-power potentiometers, both slide and rotary, are used to control audio equipment, changing loudness, frequency attenuation, and other characteristics of audio signals. = . = Variable Resistor / Rheostat (IEEE) Adjustable resistor - has 2 terminals. Some presets are accessible by a small screwdriver poked through a hole in the case to allow servicing without dismantling. Carbon-pile rheostats are used as load banks for testing automobile batteries and power supplies. The zigzag lines with three terminals represent the American standard symbol of rheostat and the rectangular box with three terminals represents the international standard symbol of rheostat…   Through digital input signals, the resistance between two terminals can be adjusted, just as in an analog potentiometer. Wire-wound rheostats made with ratings up to several thousand watts are used in applications such as DC motor drives, electric welding controls, or in the controls for generators. Il est généralement constitué d'une résistance variable dimensionnée de manière à supporter l'intensité maximale du courant devant la traverser. Type of resistor, usually with three terminals, This article is about the electrical component. Logarithmic taper potentiometers are often used for volume or signal level in audio systems, as human perception of audio volume is logarithmic, according to the Weber–Fechner law. The service life of these types of potentiometers is typically 1 million to 20 million cycles depending on the materials used during manufacturing and the actuation method; contact and contactless (magnetic) methods are available (to sense position). A linear taper potentiometer (linear describes the electrical characteristic of the device, not the geometry of the resistive element) has a resistive element of constant cross-section, resulting in a device where the resistance between the contact (wiper) and one end terminal is proportional to the distance between them. A letter code may be used to identify which taper is used, but the letter code definitions are not standardized. Un rhéostat est une résistance électrique réglable qui, intercalée en série dans un circuit, permet d'en modifier l'intensité du courant [1].Il est généralement constitué d'une résistance variable dimensionnée de manière à supporter l'intensité maximale du courant devant la traverser. It is almost always used in a ganged configuration with a logarithmic potentiometer, for instance, in an audio balance control. k The higher the percentage, the steeper the log curve.[3].

Advantages of such sensors are that only five connections to the sensor are needed, and the associated electronics is comparatively simple. {\displaystyle R_{1}=1\ \mathrm {k\Omega } } [2] The code used also varies between different manufacturers. For low-power applications (less than about 1 watt) a three-terminal potenti… Potentiometers were formerly used to control picture brightness, contrast, and color response. This results in a device where output voltage is a logarithmic function of the slider position.

A logarithmic taper potentiometer is constructed with a resistive element that either "tapers" in from one end to the other, or is made from a material whose resistivity varies from one end to the other. Usage of a digipot is far more complex than that of a simple mechanical potentiometer, and there are many limitations to observe; nevertheless they are widely used, often for factory adjustment and calibration of equipment, especially where the limitations of mechanical potentiometers are problematic. Un article de Wikipédia, l'encyclopédie libre. L In principle any relationship is possible, but for most purposes linear or logarithmic (aka "audio taper") potentiometers are sufficient. There are a number of terms in the electronics industry used to describe certain types of potentiometers: Potentiometers consist of 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. Disconnecting those two edges, and applying voltage to the other two, formerly unconnected, provides the other coordinate. , They are usually physically much smaller than user-accessible potentiometers, and may need to be operated by a screwdriver rather than having a knob. Potentiometers are commonly used to control electrical devices such as volume controls on audio equipment. Membrane potentiometer manufacturers offer linear, rotary, and application-specific variations. Alternating rapidly between pairs of edges provides frequent position updates. R

An analog-to-digital converter provides output data. The word rheostat was coined about 1845 by Sir Charles Wheatstone, from the Greek ῥέος rheos meaning "stream", and -στάτης -states (from ἱστάναι histanai, " to set, to cause to stand") meaning "setter, regulating device", which is a two-terminal variable resistor. Basically this means the center position of the potentiometer is not one half of the total value of the potentiometer. = Contamination can potentially enter anywhere along the slot the slider moves in, making effective sealing more difficult and compromising long-term reliability. The word linear when applied to a potentiometer regardless of being a slide or rotary type, describes a linear relationship of the pot's position versus the measured value of the pot's tap (wiper or electrical output) pin. Preset potentiometers are widely used throughout electronics wherever adjustments must be made during manufacturing or servicing.

A membrane potentiometer uses a conductive membrane that is deformed by a sliding element to contact a resistor voltage divider. The voltage of the top layer provides one coordinate. Another type is the linear slider potentiometer, which has a wiper which slides along a linear element instead of rotating. There is, however, always a small amount of contact resistance. For single-turn potentiometers, this wiper typically travels just under one revolution around the contact. In addition, the load resistance is often not known and therefore simply placing a variable resistor in series with the load could have a negligible effect or an excessive effect, depending on the load.   1 V

The potentiometer can be used as a voltage divider to obtain a manually adjustable output voltage at the slider (wiper) from a fixed input voltage applied across the two ends of the potentiometer. A potentiometer is a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider. Potentiometers are rarely used to directly control significant amounts of power (more than a watt or so). {\displaystyle V_{\mathrm {S} }=10\ \mathrm {V} } On règle la résistance en déplaçant le palpeur le long des spires, par l'intermédiaire d'un curseur (palpeur en translation rectiligne) ou d'un bouton (palpeur tournant). On doit le mot rhéostat (formé sur les radicaux grecs ῥέος rheos signifiant « courant », et -στάτης « état », de ἱστάναι histanai, " fixer, assigner") à Charles Wheatstone[2], qui l'introduisit en 1843 pour désigner un dipôle ayant fonction de résistance réglable. A potentiometer with a resistive load, showing equivalent fixed resistors for clarity. There are actually two, according to the IEC (International Electrotechnical Commission). 2 There are two main functional types: volatile, which lose their set position if power is removed, and are usually designed to initialise at the minimum position, and non-volatile, which retain their set position using a storage mechanism similar to flash memory or EEPROM. Potentiometers made in Asia and the USA are usually marked with an "A" for logarithmic taper or a "B" for linear taper; "C" for the rarely seen reverse logarithmic taper. It also helps in frequency modulation of waves.

For example, a light dimmer uses a potentiometer to control the switching of a TRIAC and so indirectly to control the brightness of lamps. Each end of the resistive element is connected to a terminal (E, G) on the case.