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What's the difference between a rheostat and a potentiometer?

vitaliiokolos

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Newbie here. I've been trying for a few days now to understand the difference between a rheostat and a potentiometer but to no avail. I've tried to read about it on Wikipedia and even this article with a video about rheostats https://www.derf.com/rheostat-overview-article-and-video-explanation/ but they don't really explain the difference in layman's terms.. Too many long words :) Could somebody here please explain the difference like I'm 5? Any and all help will be much appreciated. Thanks in advance
 

betwixt

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They are the same thing.
Potentiometer is the name given to the smaller scaled devices such as volume controls, Rheostat is more often used when it is a larger device that handles significant power like motor control or industrial lighting controls. Most potentiometers use carbon tracks, rheostats tend to use resistance wire, sometimes wound on a heat sink or even water cooled. There is no real border between them and the construction of each overlaps to some extent.

Brian
 

vitaliiokolos

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Thanks for your really fast and exhaustive reply, Brian. I guess I can tell the difference now )
 

reza147

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They are the same thing.
Potentiometer is the name given to the smaller scaled devices such as volume controls, Rheostat is more often used when it is a larger device that handles significant power like motor control or industrial lighting controls. Most potentiometers use carbon tracks, rheostats tend to use resistance wire, sometimes wound on a heat sink or even water cooled. There is no real border between them and the construction of each overlaps to some extent.

Brian
Hello, do not worry, there are good friends here to guide you. The potentiometer and the rheostat are both variable resistors, except that the potentiometer is used to control the voltage or potential and the rheostat is used to control the current. Because rheostats are a type of high power potentiometers. These two usually have two fixed heads and one sliding head. Depending on the type of application in the circuit can be used in different situations. 1- If we connect two fixed ends to the current circuit, then it is a fixed resistor and the sliding motion has no effect on the circuit. 2- If we connect a fixed end and a sliding end to the power circuit, then by moving the slider on one side, the resistance will decrease and in the opposite direction, the resistance of the circuit will increase, as a result, the current will increase and decrease. 3- If we connect two fixed ends directly to the power generator and connect the sliding head to the electrical circuit, then with the movement of the slider, the potential difference between the two ends of the electrical circuit will change, as a result, the current intensity will also change.
 

c_mitra

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Could somebody here please explain the difference like I'm 5?
Rheostats are variable resistance; you use them when you want to adjust some resistance value in some application. It has a movable terminal and one fixed terminal.

Potentiometers are three terminal devices and you apply a fixed potential between two ends and pick up a variable voltage at the middle (wiper) terminal. They work as voltage divider.

Construction wise, they are very similar. A potentiometer can be used a low power rheostat. A rheostat with three terminals can be used as a potentiometer. So we need not bother much except to make sure that the current and voltage ratings suit the application.

But we should call the device appropriately: if we are using a two terminal device that is being used as a variable resistor we should call that a rheostat. If the device is being used as a voltage divider, we should call it a potentiometer.

The name potentiometer came from the lab instrument in which a uniform resistance wire is used across a fixed voltage and an unknown voltage is compared with the voltage at different points on the wire. They are also called meter bridge because the wire was 1 meter long and fixed parallel to a meter scale.
 

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