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In electrical engineering, Potentiometers are devices used to measure unknown voltages by comparing them to known values. Alternatively, to put it another way, a potentiometer refers to a three-terminal device that senses potential differences by altering the resistances manually on each terminal. The voltage that is known is drawn from a cell or any source of supply.
What is a potentiometer?
A potentiometer refers to a device that detects the potential difference between two locations in electrical circuits. It is possible to determine the potential difference between two points in a circuit if we know that the potential difference between the two locations represents the effort necessary to transport a charge from one position to another. A current will flow through a point in a circuit whenever there is a potential difference between the two points. Even though it has three terminals when only two of them are used, it functions more like an adjustable resistor or rheostat. It is also known as Potentiometers or just Pots.
Potentiometer Types
Rotary Potentiometers:
The most widely used potentiometer, the wiper, travels in a circle. Potentiometers are used to provide variable voltage to a small number of circuits. The pivoting handle of a radio semiconductor volume regulator regulates the current stock toward the intensifier.
Linear Potentiometers:
The wiper travels in a straight line. Also known as a slider or fader. This potentiometer is similar to the rotating type. However, the sliding contact switched on the resistor directly. The resistor’s two terminals are connected across the voltage source. A resistor’s sliding contact can be shifted to use a resistor-related technique.
Mechanical Potentiometer
Different potentiometers exist on the market, with mechanical ones being used to modify the blockage and the device’s output. However, a mechanical potentiometer changes its opposition according to the condition. This type of potentiometer acts as a potentiometer; however, instead of rotating the handle, it may be controlled via SPI or I2C.
The main disadvantage of computerised potentiometers is that they are affected by natural variables like soil, dust, and humidity. So advanced Potentiometers (digiPOT) were created. Potentiometers can function in situations including residue, dirt, and humidity.
Digital Potentiometer:
Advanced potentiometers (digiPOTs) or variable resistors control basic indicators using microcontrollers. These potentiometers provide variable o/p opposition based on sophisticated data sources. These are sometimes referred to as RDACs (resistive advanced to-simple converters). This digit should be controlled by sophisticated signals rather than mechanical development.
Common parts of every kind of Potentiometer
Their terminals are composed of three parts: (or connection points).
Typically, they are equipped with a knob, screw, or slider that may be rotated to adjust the resistance between the centre terminal and one of the outside terminals.
The resistance between the two outside terminals is a set (constant) resistance, and it represents the highest resistance that the pot can provide. The resistance remains constant even when the knob, screw, or slider is turned.
Depending on how the knob, screw, or slider is rotated, the resistance between the centre terminal and either one of the outside terminals can range from 0 to the pot’s maximum resistance.
Components of a Potentiometer
It is made up of the following components:
Galvanometer: This is a device used to detect the presence of a little current or determine its magnitude.
Ammeter: It is an electrical gadget or equipment used to measure the flow of electric current in a circuit.
Jockey: Wire potentiometers and Wheatstone bridges employ Jockey points to create a correct connection when communication is unavailable.
Wire: Potentiometer wire is commonly made of alloys such as constantan or manganin, which have high specific resistance and a low coefficient of thermal expansion at low temperatures.
Voltage Regulators: Variable resistors, or voltage regulators, control current amounts. Change the resistance of a circuit without interrupting it with these devices.
Working Principle of Potentiometer
Its working principle is based on the fact that the drop in potential across any piece of a wire is precisely proportional to the length of the wire, given that the wire has a uniform cross-section area and that a constant current is flowing through the wire. As a result, there will be no electric current flow if there is no potential difference between any two nodes.
A potentiometer wire has high resistivity () and a uniform cross-sectional region A, and it is made of copper. As a result, it faces consistent opposition across the whole wire. Current terminology refers to the potentiometer terminal connected to the phone with a strong EMF, V, as the driving cell or the voltage source (disregarding its internal opposition). Let me represent the current flowing through the potentiometer, and R represents the total blockage caused by the potentiometer.
Following Ohm’s rule, we know that.
V = IR
We are well aware of this.
R = ρL/A
Thus,
V = I ρL/A
As ρ and A are constant and current, I am maintained constant by a rheostat; the equation is complete.
So,
L ρ/A = K (constant)
As a result of this,
V = KL
Uses of Potentiometers
Potentiometers can be used in user-controlled input applications when manual variation is required. A throttle pedal, for example, is commonly a twin gang pot intended to boost system redundancy. Joysticks, for instance, are a typical example of user-controlled input.
Pots are often used as controls in audio systems. It is employed in audio volume control systems because hearing has a logarithmic response to sound pressure. A logarithmic taper pot will naturally soften the loud to faint sounds. This is usually done with a motorised pot (with a logarithmic taper).
The most common use of potentiometers is to measure voltage. The name itself implies that. It was created to measure and regulate voltage.
These devices are employed as transducers to measure distance or angles since they translate the wiper position into an electrical output.
Pots can be used to adjust a circuit’s output. A preset pot is frequently put on the circuit board during device calibration. They are usually repaired.
A potentiometer’s key features include taper, resolution, hop-on/off resistance, and marking codes.
A potentiometer can regulate audio measure distance, angle, or voltage.
Conclusion
A potentiometer is a circuit. It compares EMF between two cells and calibrates the ammeter, voltmeter, and wattmeter. It has several uses and applications. In a circuit, a potentiometer is a device that measures the difference in potential. It is the amount of work done required to move a charge from one point to another that determines the potential difference between them. Since potential differences are there, current flows via circuits that have these differences. It’s a voltage divider with three terminals, but it may also be used as a variable resistor or rheostat with just two.
