Utmel Electronics, one of the best electrical parts distributors, provides a wide range of the best variable resistors and potentiometers. You can order pots with 1/4", 1/8" and 6mm shafts, 10k variable resistors, 100k variable resistors, 100 ohm potentiometers, PC mount, precision and trimmer potentiometers, as well as slide pots and faders with reasonable price and fast shipping. These potentiometers components and variable resistor products, with a resistance as high as 560KΩ or as low as 10Ω, come from the leading electronic components manufacturers.

What is a Variable Resistor

A variable resistor is a kind of resistor, which is able to change the value of resistance from 0 ohm to a certain value. And generally, variable resistors are used as voltage regulators and volume controls.

Types of Variable Resistors

According to resistors applications and settings, there are 4 variable resistors types as the following: Potentiometer Variable Resistors, Digital Variable Resistor, Rheostats and Trimmer Potentiometers.

Potentiometer Variable Resistors

As the most common Variable Resistor, the Potentiometer has 3 terminals. And 2 of 3 terminals are connected to the ends of a resistive element, however, the 3rd terminal is connected to an adjustable wiper, which can set the resistive divider ratio.

Digital Variable Resistor

As one of Variable Resistor types, Digital variable resistor has the ability to change electrical resistance in precise stages. And it is frequently controlled by simple up/down signals or by digital protocols like I2C. Similar with potentiometers and rheostats, Digital potentiometer changes resistance value through an integrated control unit rather than manually. And this integrated control unit receives a signal from a computer-based microcontroller, analyzes the input signal data and then utilizes it to direct the motions of a wiper similar to those used in mechanical variable resistors.

Rheostats

Rheostats are constructed similarly to potentiometers, however they are utilized as a variable resistance rather than a potential divider. Instead of the three terminals that potentiometers have, Rheostats have only two terminals: One connection is established at the resistive element's one end, while the other is made at the variable resistor's wiper. Because of the high current flowing through this type of variable resistor, heavy-duty wire-wound resistive elements are usually used. Rheostats were once employed in series with a load, such as a light bulb, as a power control device. Rheostats are no longer often used for power regulation since they are inefficient.

Trimmer potentiometers

Trimmer potentiometers, also known as trim pots, are similar to potentiometers in that they are only meant to be calibrated and set a very limited number of times by the user - often just a few times over the component's lifetime. Trimmer Pots are commonly found in huge pieces of equipment that are modified by engineers, such as audiovisual goods.

What is a Potentiometer?

A potentiometer is a voltage divider that consists of a three-terminal resistor with a sliding or revolving contact. It operates as a variable resistor or rheostat when just two terminals are utilized, one end and the wiper moves.

The resistive element may be thought of as two resistors in series (total potentiometer resistance), with the resistance ratio of the first resistor to the second resistor determined by the wiper position. The output voltage of the potentiometer is determined by the position of the wiper when a reference voltage is placed across the end terminals.

Potentiometers are frequently referred to as potmeters or pots. The single-turn rotary potmeter is the most popular type of potmeter. This sort of pot is employed in a variety of applications, including audio volume control (logarithmic taper). Potentiometers are made out of a variety of materials, including cermet, conductive plastic, carbon composition, metal film and wirewound.

How Does a Potentiometer Work?

Let's have a look at how do potentiometers do. You will always measure the maximum value (rated value) of that Potmeter if you measure the resistance between the outside terminals. In the case of a 10K ohm POT, for example, the complete 10K will be read between the outside terminals.

However, if you test the resistance between one of the outside terminals and the Wiper terminal, you'll receive a number that varies with the Wiper's location. In the instance of a 10K potentiometer, it might range from 0K ohm to 10K ohm.

You may utilize the potentiometer as a basic Variable Resistor, commonly known as a Rheostat or a Voltage Divider, depending on the terminals used.

Only two of a Potentiometer's terminals may be used as a Rheostat: one is the Wiper, and the other is one of the two outer terminals. The POT is used as a two-terminal variable resistor in this situation.

By spinning the Wiper, the resistance value rises or lowers.

Potentiometers can also be used as voltage dividers, which is a valuable use. A Voltage Divider Circuit, as you may recall, is made up of two resistors linked in series. A voltage is delivered to the resistors' ends, and the output voltage is measured across a resistor.

This straightforward circuit converts a high voltage to a low voltage. You can make a similar voltage divider using a potentiometer by connecting all three terminals.

The wiper is linked to the outer terminal of the POT, which is connected to GND of the input supply, and the output voltage is measured between the wiper and the outer terminal, which is connected to GND of the input supply.

Because you can change the resistance of a POT, you can change the Voltage Divider's output voltage. As a result, this is a variable output voltage Voltage Divider. For more information on voltage dividers calculator, if you create a voltage divider circuit and would like to calculate the voltage.

Potentiometer Types

The types of Potentiometers are available, such as Linear potentiometers, Rotary Potentiometers, logarithmic potentiometer, digital potentiometer and manually adjustable potentiometer.

Rotary Potentiometers Types: Single-turn Pot, Multi-turn Pot, Dual-gang Pot, Concentric Pot and Servo Pot.

Types of Linear potentiometers: Slide Pot, Dual-slide Pot, Multi-turn Slide and Motorized fader.

How to Read a Potentiometer Variable Resistor?

Unlike fixed resistors, Potentiometer has a wide range of resistance values. However, a broad range of values is unnecessary, due to a potentiometer resistor is variable. While potentiometers manufactures will manufacture these potmeters with every resistance value you commonly need. Therefore, the majority of potmeters fall into the following range of multiples(common potentiometer values): 10 ohm, 20 ohm, 22 ohm, 25 ohm, 47 ohm and 50 ohm. Meanwhile, the most frequent number for potentiometers is 10k ohm (10 kΩ), however other popular values include 1k ohm (1 kΩ), 5k ohm (5 kΩ), and 100k ohm (100 kΩ).

And similar with 3-digit SMD resistor coding system, Potentiometer also use a readable string to display the value of resistance. Take a 1 kΩ potentiometer as the example, its resistor code is 102, which means 10 Ω x 10^2 = 1 kΩ. Because the first digit (1) indicates the resistance value and the last digit (2) indicates the multiplier (x2).

The resistance code of a 2.5k ohm (Ω) Potentiometer is 252.
502 is the resistance code of a 5k ohm (Ω) Potentiometer.
The resistance code of a 10k ohm (Ω) Potentiometer is 103.
203 is the resistance code of a 20k ohm (Ω) Potentiometer.
The resistance code of a 50k ohm (Ω) Potentiometer is 503.

Applications of Potentiometers

Potentiometers can be used in a variety of applications and industries, such as user controlled inputs (throttle pedal in automotive applications and joysticks for machine control ), audio volume control (faders, logarithmic taper, dual-gang potentiometer), position/angel transducer to measure distances or angles (Sensors), trimpots for fabrication and calibration (such as presets, trimming potentiometers/trimmers).

Guide to Buy Potentiometer and Variable Resistors

Top 10 Potentiometer Manufacturers

The top 10 famous variable resistors are Amphenol, ALPS, Bourns, Inc., CTS Corporation, Honeywell, Panasonic, TT Electronics, Vishay, Ohmite, Nidec Copal Electronics.