Potentiometer, principle, types, uses

What is potentiometer?

A potentiometer, often referred to as a potentiometer, is an electrical component used to change the resistance in a circuit. It is a three-pole device with a sliding or rotating contact that can be adjusted to regulate the voltage or current in a circuit.

Who devolped potentiometer?

The development of the potentiometer is credited to Johann Christian Poggendorf, a German physicist who invented it in 1841. Initially, Poggendorf created a potentiometer as a device for measuring electrical potentials (voltages). His design consisted of a taut wire of equal resistance, along which a sliding contact could be moved to measure the potential difference between various points.

Since Poggendorff's first invention, the potentiometer has been further developed and improved by various scientists and engineers. Over time improvements have been made in terms of materials used, methods of construction and adding features such as multiple bends or digital control. These advances expanded the scope and capabilities of potentiometers in the field of electronics.

On which principle the potetiometer works?

The potentiometer works on the principle of voltage division. When voltage is applied to the two outer terminals of the potentiometer, some of that voltage is removed from the wiper terminal. The magnitude of the discharged voltage is determined by the position of the cursor along the resistive element.

A fixed voltage is applied across the ends of the potentiometer's resistive element. It can be thought of as a voltage divider where the resistive material provides a continuous range of resistance. As the scraper moves past the resistance element, the resistance ratio between the scraper conductor and one of the outer conductors changes.

According to Ohm's law (V = I × R), the voltage across a resistor is directly proportional to the current flowing through it and the amount of resistance. In the case of a potentiometer, as the slider is moved, the effective resistance between the slider's terminal and one of the outer terminals changes. This also causes the voltage at the wiper connection to change proportionally.

By adjusting the position of the slider, it is possible to change the output voltage of the potentiometer within the range determined by the applied voltage. This voltage can then be used for various purposes, such as controlling other components in the circuit, measuring voltage levels, or providing user-configurable parameters.

In general, the principle of voltage division allows potentiometers to provide a variable output voltage depending on the position of the cursor along the resistive element, allowing precise control and measurement of the electrical potential in the circuit.

Types of potentiometer:

Different types of potentiometers are available for different applications and mechanical configurations. The main types of potentiometers are:

Rotary Potentiometer:

This type, also known as knob potentiometer or rotary potentiometer, has a rotating shaft and a round resistance track. The wiper moves in a circular pattern as the shaft rotates. Rotary potentiometers are typically used for applications that require continuous adjustment, such as volume control on audio devices or tuning controls on a radio.

Linear Potentiometer:

Linear potentiometers have a linear resistive element, often in the form of a strip or track. The wiper rides on a linear guide for linear adjustment. They are often used in applications that require linear position sensing, such as motorized sliders or faders on mixing consoles.

Trimmer Potentiometer:

Trimmer potentiometers, also known as trim pots, are miniature potentiometers designed for fine tuning or calibration. They are often used during the manufacturing or assembly process to set or fine-tune some parameters of electronic circuits. Trimmers are usually pre-installed and then soldered or mounted directly to the PCB.

Multi-turn potentiometer:

Multi-turn potentiometers are designed to provide precise and precise adjustment over multiple revolutions of the shaft. They usually have multiple resistor and wiper traces, allowing for high-resolution tuning. These potentiometers are often used in applications where precise and precise control is required, such as scientific instruments or measurement equipment.

Digital Potentiometer:

Digital potentiometers are electronic devices that digitally simulate the operation of a potentiometer. They use electronic switches and resistive networks to provide adjustable resistance. Digital potentiometers can be controlled digitally via a microcontroller or other digital interface, making them ideal for applications requiring automatic or remote control.

These are some of the most commonly used types of potentiometers. Each type has its own characteristics, advantages and suitable applications, creating a wide range of control and measurement possibilities in electronic circuits.

Uses:

Potentiometers are widely used in various electronic and electrical systems. Here are some common uses for potentiometers:

Volume control:

Potentiometers are commonly used in audio systems to control the volume level. It allows users to adjust the resistance and therefore the level of the signal passing through the circuit, resulting in a change in the intensity of the sound.

Brightness control:

Potentiometers can be used in lighting systems, displays or monitors to adjust brightness levels. By changing the resistance, you can control the current to the light source, which leads to a change in brightness.

Speed control:

Potentiometers are used in motor control circuits to control the speed of electric motors. By changing the resistance, it is possible to change the voltage or current supplied to the motor, thereby controlling the speed of rotation.

Sensors and Measurements:

Potentiometers can be used as position sensors in robotics, joysticks or control buttons. The position of the scraper along the resistive element provides feedback on its physical position or displacement, allowing for accurate measurement and control.

Calibration and adjustment:

Potentiometers, especially potentiometers, are used to calibrate and fine tune electronic circuits. It allows you to fine-tune parameters such as voltage, current or frequency to achieve the desired performance or calibration accuracy.

Temperature control:

Temperature control systems can use potentiometers to adjust temperature set points. It allows users to set the desired temperature by changing the resistance and then controlling the heating or cooling elements.

Oscillator Frequency Control:

Potentiometers can be used to adjust the frequency of oscillators, such as those in radio transmitters or synthesizers. By changing the resistance, the timing components of the oscillator circuit can be changed, resulting in frequency adjustment.

User Interface Controls:

Potentiometers are commonly used in various user interface controls such as knobs, sliders, or rotary knobs on electronic devices. They provide users with a convenient and intuitive way to interact and set parameters in electronic systems.

These are just a few examples of the many uses for potentiometers. Their versatility, ease of use, and ability to provide variable resistance or voltage regulation make them valuable components in a wide variety of electronic systems and devices.