The Measurement Shop's Guide to Potentiometers

What is a potentiometer?

A potentiometer, also called a potmeter or pot, is a variable resistor or voltage divider that you can manually adjust with three terminals used to control voltage. This blog will discuss the types of potentiometer, answer the question "how does a potentiometer work" and give insight on what you can use them for.

How does a potentiometer work?

Potentiometers consist of three pins or terminals that that connect to a resistive element and adjustable wiper. Two of the terminals (blue and green) connect to the resistive element whilst the wiper connects to the third terminal.  The wiper travels along a strip when you turn the dial and the movement differs depending on whether you are using a potentiometer with linear or rotary movement.

What can you use a potentiometer for?

You would typically use a potentiometer as a voltage divider. However, they are particularly useful in circuits to effectively control current by changing resistance in certain ways. 

A common use for potentiometers is for volume/ sound control on musical instruments such as guitars. However, many rely upon them as part of complex electrical circuits in engineering, automotive and industrial applications.

How to wire a potentiometer

Before starting you will need to ensure that you have all the appropriate tools to hand, and have a clear working area. Place the potentiometer on a flat surface with the shaft facing upwards. Tools you will need: a length of wire, soldering tool, voltmeter, rotating dial.

1. Locate the three terminals – Potentiometers consist of three terminal points, you will need to identify each point before continuing. We recommend labelling each point with either a number or the relevant colour to avoid confusion.
2. Attach the first terminal – To provide the grounding of the pot, use terminal one. Solder one end of the wire to terminal 1 and the other to the component’s chassis. By grounding the potmeter, you will be able to reach zero when at the minimum position.
3. Wire the second terminal – The second terminal is for the potentiometers input, therefore connect the output line from the given circuit. Solder the wire onto the terminal following the same method as before.
4. Wire the third terminal – The third terminal is for the potentiometers output, therefore you should connect this to the circuit's input. Solder the final wire following the same steps as before.
5. Test the potentiometer – Once you've attached all thew wires, use a voltmeter to test that the potentiometer works. To do this, connect the leads of the voltmeter to the input and output terminals (2 and 3) and turn the shaft. By turning the shaft, the reading on the voltmeter should change.
6. Carefully place the potentiometer inside an electrical component – After you have successfully tested the pot you can position this as needed into an electrical component. At this stage you can also connect a dial for voltage control if desired.

Please see Wikihow’s article on wiring a potentiometer to learn more.

Types of potentiometer

There are many types of potentiometer to choose from; however we have produced a brief list of some of the most popular potentiometer types available:

Industrial

Industrial potentiometers are heavy-duty devices constructed with durable metal or plastic casing. This makes them capable of withstanding rigorous use in tough engineering applications. These potentiometers are built-to-last and provide added protection over other types of potentiometer. They are often used in severe working conditions and military-grade engineering.

Automatic/ digital

An automatic digital potentiometer, or auto pot, is a device that has been customised to allow you to control a voltage splitter with digital signals. As these devices are not controlled mechanically, they can be configured to ‘sweep’ in a linear or logarithmic fashion.

Micro/ mini

Mini or micro potentiometer is a small, practical electronic component used to control voltage. These potentiometers easily fit into small electrical components and are often attached to circuit boards.

Multi-turn

Multi-turn potentiometers operate on a rotary, gear function in order to select multiple levels of precision and resistance. These potmeters are typically used for measuring angles, distances and rotations.

Trimmer

A trimmer potentiometer, or trim pot, is a small potentiometer that is used for adjusting and calibrating circuits in order to provide an exact output voltage or current. Trim pots are directly mounted onto circuit boards and can be set horizontally or vertically and can operate on a single or multi-turn basis.

Linear/ slide

Linear or slide potentiometers refer to digital potentiometers where the wiper moves across a linear path rather than through a rotary motion. Resistance output varies according to the displacement or potion of the slide or wiper.

Motorised

Motorised potentiometers are devices that operate on a slide movement which is driven by a belt small motor system. These devices are particularly useful for jumping back to pre-set positions and are often used in tension motors, flow meters and speed controls.

Rotary

Rotary potentiometers are used to convert rotary movement into a proportional voltage. These potentiometers are used for vehicles with four wheel steering control, for example, road sweepers as well as foil packaging machines used in product manufacturing.

Stereo

Stereo potentiometers are compact electrical devices used to control audio voltage for use in automotive audio systems, lighting controls, video equipment and synthesizers.

Volume

One of the most common potentiometer types. Volume or audio pots are used to for volume control (logarithmic taper) in electrical-based musical instruments such as guitars.

Dual

Dual potentiometers, also known as dual-gang pots, feature two potentiometers combined on the same shaft. This enables parallel setting of two channels. These devices are commonly used for balance controls.

Precision

Precision potentiometers are designed for control applications where precision, accuracy and a high-level of readability are required. They are commonly used for lighting controls, speed controls, medical equipment, joysticks and position sensors.

Taking care of potentiometers

Potentiometers can be sensitive electrical devices, therefore you will need to ensure that all electrical components and wires are regularly checked and cleaned in order to increase longevity.

Cleaning a potentiometer

1. Ensure all wires have been disconnected and all electrical devices connected to the potentiometer have been switched off and removed.
2. Spray the potentiometer with a standard alcohol-based cleaner that does not leave a film (therefore we advise against using any lubricant-based products).
3. Rotate the potentiometer to remove any dust/ material build-up
4. Once rotated spray again with the cleaner and repeat until the whole potentiometer has been covered.
5. Once covered, leave the potentiometer to dry completely.
6. After cleaning, add dielectric grease to ensure easy, unhindered movement.

(Note: rather than spraying, it is possible to soak or submerge the potentiometer instead before rotating, however please ensure that any internal electrical components have been removed before doing so.)

Buying a potentiometer

When buying a potentiometer, you will need to ensure that you have considered all the necessary questions to do with operation, intention and budget. We have provided a brief checklist of things to consider before buying a potentiometer.

• Intention

When choosing a potentiometer to buy, you will need to consider how you intend to use the device. For example, if you are working in harsh warehouse environments, an industrial potentiometer would be a suitable choice, however if you are looking at steering control then you may require a rotary potentiometer.

• Construction

How and what the potentiometer is constructed from can impact how the device can be used. There are many types of construction used for potentiometers including lightening protection, high-grade temperature resistance, waterproof plastic housing, non-conductive housing etc.

• Specifications

When buying a potentiometer, it is important to check the individual specifications of each model as resistance, rotation and electrical range will differ. We recommend choosing a model with slightly more range or resistance than needed to ensure that you are fully covered here.

• Cost

One of the main considerations to make before buying any product. We recommend forming a budget that allows you to buy a potentiometer that will meet all your needs for the foreseeable future rather than the here and now.

TMS potentiometers for sale

IGP Heavy Duty Geared Potentiometer

Novotechnik's IGP heavy-duty geared potentiometer has a maximum angular rotation of 3800° that can be converted into a voltage proportional to the angle of rotation. Gearwheels or chain drives can be used to directly drive the shaft where necessary.

SP2800 Automotive/ Industrial Rotary Potentiometer

Automotive rotary potentiometer for industrial engineering. The SP2800 is an industrial-grade potmeter with high-grade, temperature-resistant plastic construction. This device is used to convert rotary movement into a proportional voltage and is perfect for four wheel steering control.

P2200 Low Torque Rotary Potentiometer

Novotechnik’s P2200 rotary potentiometer features exceptionally low torque that is perfect for applications where the repercussions of the driving shaft could lead to measurement faults. Excellent linearity, good repeatability and unrestricted continuous rotation.

P6500 Standard Potentiometer

A standard long-life, precision potentiometer for measuring control applications. Novotechnik’s P6500 is constructed from an al metal case with conductive resistance element and elastomer-damped wipers.

AWS 360ZE Heavy Duty Potentiometer

The AWS 360ZE is a heavy duty potentiometer that comes with durable, waterproof casing. This model is perfectly suited to industrial plants and heavy engineering.

IPE6000 Heavy Duty Potentiometer

Novotechnik's IPE6000 potentiometer is a heavy-duty device equipped with a signal interface integrated in the case. This model has been fitted with an electronic system using SMD technology for control of the supply voltage and transformation of angle-proportional voltage into an output current.