Hello readers welcome to the new post. In this post, we will learn What is a Potentiometer. The potentiometer is an electronic component used for measuring and controlling of resistance of the circuit. In this, post we will learn different parameters about potentiometers such as construction, types, uses, working principles, and applications. So let’s get started What is a potentiometer?
What is a Potentiometer?
- The potentiometer is an electrical component used for varying the resistance of the circuit. It has a resistive element that is long shape and thin and generally comes with a cylinder shape that is made with carbon, ceramic, or conductive plastic. On it wiper connected that moves over its length or cylinder shape structure
- Wiper is made of metallic material contact that varied with the use of a knob or lever to change the position of the resistive component.
- The resistive component is divided into three parts that are two endpoints and a wiper terminal
- When voltage is provided at two ends of points current flows through the resistive component and voltage loss about the element is directly proportional with resistance in the wiper and end terminal.
- With changes the position of wiper resistive element resistance in the wiper and end terminal is changed providing vols and current in the circuit or varied
- The main reason to use this component in circuits is their application to control volume and tone controls in audio amplifiers. They also control contrasts and brightness in display devices and position sensors in robots and automation systems.
- It is also used in scientific instruments to measure and control electrical signals that are oscillations and signal generators
Construction of a Potentiometer
- There are main parts of the potentiometer resistive element, a wiper, and two terminals. Carbon is used to make resistive elements and can be linear or rotary in shape.
- The wiper is generally created with conductive material moving about the resistive elements making a variable voltage divider.
- The two terminals are connected to the end point of the resistive element while wiper terminals provide output voltage.
Types of Potentiometers
main types of potentiometers are that are rotary, linear, multi-turn, and digital.
Linear Potentiometer
- This type of potentiomer has a resistive element in a straight line offering linear changes in resistance. it is used in volume controls, faders, and linear position sensors. This potentiometer is similar but the difference is that instead of rotary motion the sliding contact gets moved on the resistor linearly.
- The two ends of the straight resistor are connected with the source voltage. The sliding contact can slide on the resistor through a track connected with a resistor. The terminal connected with sliding is connected to one point of the output circuit and one with terminals of resistors is connected to the other end of the output circuit.
- This potentiometer is used for measuring voltage about the circuit branch, to measure the inner resistance of the battery cell for comparison battery cell with the standard cell. It is used in the equalizer of music and sound mixing systems.
Rotary Potentiometer
- It has a resistive element in a circular shape that offers circular changes in resistance. it is mostly used in switches, knobs, and rotary position sensors. Rotary potentiometer used for getting adjustable supply voltage to electronic circuits and electrical circuits. The volume controller of the radio transistor is a common example of a rotary potentiometer where rotary knob controls supply to the amplifier.
- This potentiometer comes with 2 terminal contacts between which uniform resistance is positioned in semi semi-circular pattern. The device also comes with a middle terminal that is connected to resistance through sliding contact connected with the rotary knob.
- Through a rotating knob, we can move sliding contact on semi-circular resistance. The voltage is taken between resistance end contact and sliding contact.
- The potentiometer is also called POT. POT is used in substation battery charges for adjusting the charging voltage of the battery. There are many uses of rotary potentiometers where smooth voltage control is needed.
Multi-turn Potentiometer
- The multi-turn potentiometer has a resistive element that rotates many times and offers a high resolution of resistance variation.
- it is used in accurate instruments like oscilloscopes, and position sensors.
Digital Potentiometer
- it is an electronic component that controls the functions of a mechanical potentiometer. It comes with a set of resistive elements and switches which used to regulate in digital form.
- It is used in audio and video instruments and industrial control systems
- The digital potentiometer is 3 terminal instruments, two fixed-end terminals, and one wiper terminal that is used for changing output voltage.
- Digital potentiometer comes with different uses such as celebrating systems, adjusting offset voltage, tuning filters, controlling screen brightness, and controlling sound volume
- The mechanical potentiometer has many disadvantages that make it not useful for uses where accuracy is needed.
- Size, wiper contamination mechanical wear, and resistance drift humidity are some disadvantages of a mechanical potentiometer. To minimize these disadvantages digital potentiometer is the best to house as it has high accuracy.
Advantages of Digital Potentiometers
- It offers reliable operation
- it has high accuracy
- It is small in size, multiple potentiometers can be configured on one chip.
- it has very little resistance drift
- It does not have a moving part
- it has less effect on environmental conditions such as vibrations, humidity, shocks, and wiper contamination.
- Its tolerance is ±1%
- Its dissipation power is low about tens of milliwatts
Disadvantages of Digital Potentiometers
- It is not best for high-temperature conditions and high power uses.
- Due to the parasitic capacitance of electronic switches, there are bandwidth factors that are in digital potentiometers. That is the highest signal frequency that can cross-resistance terminals that less thatn 3 dB attenuation in the wiper. The transfer equation is like to low-pass filter.
- The nonlinearity in wiper resistance added harmonic distortion to the output signal. The total harmonic distortion or THD defines the degrees to which the signal is degraded after crossing the resistance
Potentiometer Driver Cell
Potentiometers measure voltage by comparing measuring voltage with voltage about the resistance of the potentiometer. For the operation of a potentiometer, there should be a voltage source connected to the potentiometer circuit. This cell offers a voltage source to drive a potentiometer called a driver cell.
The driver cell provides current through the resistance of the potentiometer. The multiple of current and resistance of the potentiometer offer full-scale voltage of the device. By adjusting this voltage we can vary the sensitivity of the potentiometer.
It is normally done by adjusting the current through resistance. The current passing through resistance if regulated by the rheostat connected in series with the driver cell. So it is known that the voltage of the driver cell should be higher thatn the voltage measured.
Uses of Potentiometers
- Potentiometers provide different uses in electronics, such as volume control, light dimming, joystick controls, temperature control voltage division, and signal attenuation
How to Select a Potentiometer?
- There are some factors follow for the selection of a potentiometer
- Resistance value: it comes with different values of resistance. Choose the value of resistance that is according to the project’s need
- Power rating: the power rating is the value of power handled by the device without getting damaged. Make sure the selected potentiometer has such rating that can handle the power of the circuit connected.
- Taper: It defines that resistance changes by turning the knob. The most used taper types is linear and logarithmic. Choosetaper that has larger turns. Several turns define how rotations are needed to move from low to high resistance value
- Size: The size of potentiometers is also the main factor for their selection. It must be according to the circuit need
- Environmental factors: Also consider some environmental factors such as temperature, vibration humidity. So use such a meter that can handle all these parameters
Working Principle of Potentiometers
- Working principle based on variable resistance concept. In a potentiometer, a resistive component comes with uniform resistance over its length. It is made of carbon, cermet or conducive plastic
- The wiper is connected with a resistive element and moves over its length. It is made with the conductive material of any metal and connected with a third terminal.
- For understanding the working of this device take an example circuit with a battery, potentiometer, and resistance.
- The resistance between the wiper and one end point of the potentiometer reduces when the wiper moves to that point and the resistance between the wiper and other points decreases.
- So the voltage across resistance changes and the voltage at the output of the potentiometer varies. By setting the position of the wiper we can regulate the output of the potentiometer
- The potentiometer can be used in AC and DC circuits. In DC circuits it is used as a variable resistor and in AC circuits it is operated as a variable voltage divider
- quality of resistive element size and wiper type and mechanical stability of the potentiometer define the accuracy and regulation.
- High-quality potentiometers come with less tolerance and good linearity and can come with correct and precise voltage control
Applications of Potentiometer
Volume Control
- The linear potentiometer is used as a volume control in speakers and amplifiers. The wiper of the potentiometer is attached to the input of the amplifier or speakers and the output is attached to the terminals. By adjusting the position of the wiper volume of sound can be increased or decreased
Light Dimmer
- it is also used in light-dimming circuits. The rotary potentiometer is used as a dimmer switch in lamps and lighting systems. The potentiometer is attached with a triac that controls the current that flows in the lamp. By varying the position of the wiper brightness of the light can be varied
Joystick
- It is used as a joystick for video games and other uses. The rotary potentiometers are used to measure the position of the joystick and send feedback to the controller. The position of the joystick can be used for regulation of the motion of characters or objects in-game
Temperature Control
- The linear potentiometer is used for temperature measurement and the output voltage is given to control the heating or cooling system. Changing the positions of the wiper, the temperature can be set at the required value
Signal Attenuation
- The linear potentiometers are also used to control the amplitude of the signal and decrease the noise level of interference in the signal. The potentiometer is configured with the input of the amplifier or receiver and the output is attached to the terminals
Potentiometric Sensors
- They are used as potentiometer sensors in different projects. The potentiometer sensors measure the displacement, position, or angle of an object by converting it into a change in resistance. It is attached to an object and the wiper is attached to the voltage source the changes in displacement or position of object registration of the potentiometer vary with changes in the output voltage
Potentiometer as a Voltage Divider
- The potentiometer is used in electronic circuits as a variable resistor. it comes with a resistive track which varies with turning the knob or slider, which varies the resistance between two terminals.
- When connected as a voltage divider potentiometer is used to produce voltage output from the fixed voltage input
- it is connected as a series combination with load, input voltage is provided about two outer terminals of the potentiometer.
- The load is between the wiper terminal and one of the external terminals of the potentiometer.
- With varying positions of wiper resistance between the wiper and external terminals can be changed varies voltage about the load.
- The voltage of the load can be measured through the voltage divider formula:
Vout = Vin * R2 / (R1 + R2)
- Here Vin is the input voltage R1 is the resistance between the wiper and one external terminal, R2 is the resistance between the wiper and the 2nd external terminal and Vout is the voltage of the load
- Varying the position of wiper ratio R2 to (R1 + R2) changes that varies output voltage Vout. Potentiometers are used in electronic circuits as variable voltage are used like in audio volume controls, dimmer switches, and variable power sources
Potentiometers as a Variable Resistor
- Potentiometer has a resistive length which can change by turning the knob or slider that varies resistance between two terminals.
- The resistance of the potentiometer can be varied to a certain value by rotating the knob or slider. It makes it beneficial in different applications where variable resistance is required, like volume controls or tone controls for audio equipment.
Potentiometer vs Voltmeter
Difference Between Potentiometer & Voltmeter
Potentiometer | Voltmeter |
---|---|
It is an electronic component that is used as a variable resistor. | It is an electronic instrument used for voltage measurements |
It has a resistive track that can change by turning the knob or slider | It has a display that indicates the voltage measured |
It can work as a voltage divider to generate a variable voltage | Cannot produce a voltage output |
Often used in electronic circuits where variable resistance is needed | It is used to measure the voltage of the circuit elements |
It works based on the zero-deflection method | It based on the deflection method |
Its sensitivity is high | it is low sensitive component |
It is attached in series to load for making variable voltage | It connected to a parallel for voltage calculation |
It is used for the adjustment of LED brightness and speed of the motor | It can vary circuit parameters |
It can be used for calibration of an ammeter and voltmeter | It measures the emf |
Advantages of Potentiometers
- It has a simple structure and is easy to use.
- Potentiometers have high resolution and accuracy making them best for precision projects
- They come with different ranges of resistance and provide a broad range of voltage
- They come in different types and sizes so provide flexible designs.
Disadvantages of Potentiometers
- it can be affected by temperature and humidity that causes changes in resistance values
- They can produce noise and interference in circuits if not properly configured and protected
- They have a limited lifespan, especially for high-power projects
Conclusion:
Potentiometers are the main component of electronic circuits since they provide a fast and simple technique to measure resistance in a circuit. it is best for projects like volume controllers, and precision instruments, and comes in in a variety of forms and sizes. You can use this device according to your project need and before using it must know about its construction, uses, workings, and applications of potentiometers..
Read Also:
FAQs
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Write the Difference Between a Potentiometer and a Rheostat.
- The potentiometer has 3 terminals with variable voltage output and the rheostat has two terminal resistors having variable resistance output. Potentiometer used to voltage control and rheostat control current in the circuit
Read Also https://www.theengineeringknowledge.com/difference-between-potentiometer-and-rheostat/
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Potentiometers Used in High-Power Applications.
- Potentiometers are used in high-power projects but have a limited lifespan since they cause noise and interference
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Write the Working Principle of a Potentiometer.
- The working of a potentiometer based on changes in resistance about the length of a resistive element that is regulated through a change in the wiper
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How to Select the Right Type of Potentiometer for My Application?
- We can select the right potentiometer by measuring factors like resistance value, power rating, tolerance, and type of application.
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Write the Main Types of Potentiometers Used in Electronic Circuits.
- The main types of potentiometers used in electronic circuits are multi-turn, rotary potentiometers, and linear potentiometers.
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What is a potentiometer used for?
- The potentiometer is used as a voltage divider or variable resistor in a circuit. Some uses are dimmer switches for lights, brightness controls in TVs, and faders in audio instruments.
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What is a potentiometer a device used to?
- The potentiometer is used for measuring electrical potential. It is one type of uniform high-resistance wire connected with insulating support, marked with a linear measuring scale