Potentiometers

A potentiometer is a three-terminal resistor with a sliding or rotating contact that creates an adjustable voltage divider. So if only two terminals are used, one end and the wiper, it will act as a variable resistor or rheostat.

This particular type of voltage measuring instrument helps in measuring electrical potential voltage. This component is an implementation of the same principle. And this is where the name come from. The potentiometers commonly help in controlling electrical devices like audio equipment or volume control. These devices operate with the help of a special mechanism. With that, you can use these devices as position transducers. Let’s say in the joysticks. At times they also help in controlling significant power (usually one more than a Watt).

Types of potentiometers

With the advancement in technology, the experts have introduced different types of circuits to meet the varying g needs of the machines and the users. There is also a wide variety of supporting tools and accessories available in the market. The same implies to potentiometers. To make the job easier for any layman, the manufacturers offer a wide variety of potentiometers in the market. Today, we will mention some prevalent potentiometers that you can use in small to large-sized circuits.

Digital potentiometer

These are three-terminal devices with two fixed end terminals. One of these wipers helps to vary the output voltage.  These potentiometers have varying applications like calibrating a system, tuning filters, adjusting the offset voltage, controlling sound volumes or controlling screen brightness. However, this potentiometer has some severe disadvantages, making them unsuitable for applications where you need more precision. Wiper contamination, size, mechanical wear, sensitivity to vibration, resistance drift, and humidity are some of the main disadvantages of these devices.

Membrane potentiometers

They use a conductive membrane that is deformed by a sliding element to contact a resistor voltage divider. The linearity can range from 0.5% to 5%, depending on the design, material, and manufacturing processes. They are impressive for the fact that here you need only five connections to the sensor. Also, the associated electronics is comparatively simple. Another advantage is that any material that depresses the top layer over a small area works impressively. However, a significant disadvantage is that you must apply sufficient force to make contact. The sensor also requires occasional calibration to match the touch location to the underlying display.

Rotary potentiometers

These potentiometers help to obtain adjustable supply voltage to a part of electronic circuits and electrical circuits. For example, the volume controllers on a radio transistor are the most common example of a rotary potentiometer where a rotary knob of the potentiometer controls the supply to the amplifier. These devices have two terminal contacts, between which a uniform resistance is located in a semicircular pattern. It also contains a middle terminal connected to the resistance via sliding contact attached with a rotary knob. As it supplies smooth voltage, it is a versatile option available in the market.

Linear taper potentiometer

Instead of a rotary movement, these devices contain a sliding contact that gets the resistor moving in a linear position. Here two ends of a straight resistor are connected across the source voltage. This sliding contact can be slid on the resistor through a track attached along with the resistor. When the terminal connects to the sliding, it is connected to one end of the output circuit. One of the terminals of the resistor is connected to the other end of the output circuit. These potentiometers are used to measure the voltage across the branch of a circuit and measure the internal resistance of the battery cell. It is also used for comparing the battery cell with a standard cell.