Mostly used to regulate the current flow by adding/subtracting resistance from the circuit, these resistors are available in many shapes and sizes. Some of the applications are listed below, categorically: Pots can be used in a circuit, to tune them to get the desired output. Draw a circuit diagram used to compare the emfs of two primary cells. Circuit diagram. Now a closer look into the figure, we can see that at the current position of wiper, there are two resistive paths just like the resistor is split into two resistors. of two cells and potential difference across a resistor. (b) In a potentiometer, a standard source of emf 5V and negligible internal resistance maintains a steady current through the potentiometer wire of length 10m. Our webiste has thousands of circuits, projects and other information you that will find interesting. (electromotive force) of two cells, to measure the internal resistance of a cell, and potential difference across a resistor. Now that we have discussed the working principle, lets now learn how this passive device is constructed. Geometry of the resistive strip whether it is an arc or a straight strip, decides the geometry of the potentiometer. Sep 14,2020 - Describe a potentiometer Related: NCERT Solutions - Current Electricity? The positive terminal of the cell of emf E and internal resistance r is connected to the higher potential terminal A of the potentiometer, the negative terminal is connected through a center-zero galvanometer to a pencil jockey. We have a resistive track whose complete resistance will be equal to the rated resistance value of the POT. Learn about Potentiometer Working topic of Physics in details explained by subject experts on vedantu.com. In a potentiometer, the entire input voltage is applied across the whole length of the resistor, and the output voltage is the voltage drop between the fixed and sliding contact as shown below.A potentiometer has the two terminals of the input source fixed to the end of the resistor. Calculate the total series resistance, the current flowing through the series circuit and the voltage drop across the 50 ohm resistor. This article deals with the working principle, construction and application of a potentiometer. Voltage drop across R2 = 50Ω can be found by voltage division rule, that iseval(ez_write_tag([[300,250],'circuitstoday_com-leader-1','ezslot_4',113,'0','0'])); Here we see if we change the value of either R1 or R2the value of the voltage across any one of the resistors will be in the range of 0-10V, provided that the total resistance of the circuit remains constant. The name itself has that implication. How can the sensitivity of a potentiometer be increased. The current flowing through the circuit will be I = V/R =10/200 = 0.05A. The working principle can be made clearer, by solving the example below. In the circuit diagram shown below, the terminals of the potentiometer are marked 1, 2 and 3. Potentiometer working can be explained when the potentiometer is understood. Out of its three terminals, two of them are fixed and one  is a varying (linear / rotary) terminal. (a) Working Principle of Potentiometer Principle:Consider a long resistance wire AB of uniform cross-section. Let us assume a 10k potentiometer, here if we measure the resistance between terminal 1 and terminal 3 we will get a value of 10k because both the terminals are fixed ends of the potentiometer. It is very easy to understand the purpose of these terminals by looking at the diagram below. State the principle of potentiometer. Mostly the potentiometers what we find has a wiper that rotates over an arc shaped resistive material, there is another type of pot where the wiper slides linearly over a straight resistive strip. Now, let us place the wiper exactly at 25% from terminal 1 as shown above and if we measure the resistance between 1 and 2 we will get 25% of 10k which is 2.5K and measuring across terminal 2 and 3 will give a resistance of 7.5K. Potentiometer is a device used to compare the e.m.f. across total length L of the wire AB. In many cases, a ohm, 1/4-watt resistor and a 5K-ohm potentiometer will work well.As the symbol suggests a potentiometer is nothing but a resistor with one variable end. It is defined as a three-terminal resistor having either sliding or rotating contact that forms an adjustable voltage divider. Thank you for your answer. E 4.1(a). The pin diagram of the Trimpot potentiometer is shown below. Instead of long wire small pieces of wire is taken and each of those pieces are fixed parallel to each other on a platform. Higher the length, higher is the resistance, provided the material of the resistor and its cross-sectional area remains same. The potentiometer is a device used to measure the internal resistance of a cell and is used to compare the e.m.f. The potentiometers or the “pots”, as it is commonly known in the electric circles, is a three terminal variable resistor. potentiometer pdf, potentiometer ... potentiometer class 12, potentiometer pinout, cbse 2020 question. NCERT Solutions for Class 12 Physics Chapter 3 Current Electricity includes all the important topics with detailed explanation that aims to help students to understand the concepts better. Discuss your doubts related to CBSE or NIOS boards with us and other users through Discussion Forum and get the proper suggestions. Download Free solutions of NCERT physics Class 12th from SaralStudy. To compare the emf’s of two given primary cells using a potentiometer. Adjust potentiometer R 1 until the upper voltage limit is reached, as indicated by the voltmeter. Hence, the name “potentiometer” was given to this device, which is coined from the combination of two words: potential difference and metering. If only two terminals are used, one end and the wiper, it acts as a variable resistor or rheostat.. Even though the basic construction and working principle of potentiometers are the same, they differ in one aspect that is the geometry of the moving terminal. Potentiometers also known as POT, are nothing but variable resistors. Like for example a throttle pedal is often a dual gang pot, used to increase the redundancy of the system. Potentiometer Working - Principle & Diagram × Sorry!, This page is not available for now to bookmark ... NCERT Book Solutions. They are passive in nature, therefore dissipate power rather than supplying power to the circuit. Two terminals are fixed, one is a sliding contact. Potentiometer A potentiometer consists of a uniform wire AB of low temperature coefficient of resistance stretched over a uniform wooden scale Fig. When the wiper is at terminal 1, R1 becomes zero and the voltage across the wiper is same as the supply voltage. One must have prior knowledge of what a code stands for. Resistive strip can be composed of carbon, or may be wire wound. instead of another model? Potentiometer. Most common application of potentiometer is as voltage measuring devices. All rights reserved, STM32F2 Series High-Performance Microcontrollers, STM32F4 Series High-Performance Microcontrollers, STM32F7 Series Very High-Performance Microcontrollers, STM32F0 Entry-Level ARM® Cortex®-M0 Microcontrollers, STM32F1 Series Mainstream Microcontrollers, STM32F3 Series Mixed-Signal Microcontrollers, STM32WB5MMG - STM32 Wireless MCU Module for Increasing Design Productivity of BLE and IoT Devices, Digi-Key Becomes Official Raspberry Pi Authorized Distributor and Will Carry the Full Line of Raspberry Pi Products. Now that we have had an introduction about the potentiometer, you might have a curiosity of knowing how it looks like. In a potentiometer arrangement, a cell of emf 1.25 V gives a balance point at 35.0 cm length of the wire. This potentiometer includes a knob over it and it is used to change its value by changing it. NCERT Solutions for Class 12 Computer Science (Python) ... To Compare The EMF of Two Given Primary Cells Using Potentiometer. The terminal 2 is connected to the wiper. The position of the wiper determines how much resistance the potentiometer is imposing to the circuit, as the figure demonstrates: Figure 1 shows some practical pots, while figure 2 shows the standard symbol of the same. Since the two resistance are in series, total resistance R = R1 +R2 = 200Ω. The diagram shows the parts present inside a potentiometer. A potentiometer is a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider. Type above and press Enter to search. NCERT. This is due to the fact that resistance of a resistor depends on its length (since R=ρ). CBSE Class 10th Board Examination for Science is due to be held tomorrow i.e. This very concept is the principle behind the working of a potentiometer. The value of the resistance can be changed from zero to a defined upper limit, by just manually sliding the contact over a resistive strip. NCERT Exemplar Class 12 Physics is very important resource for students preparing for XII Board Examination. Write the formula used. The potentiometer essentially has a resistive element over which a moving terminal, the wiper slides. What is Potentiometer – Diagram , Working , Advantages What is Potentiometer. Skip to main content Physics Tutorial ncert physics class 12 solutions, ncert ... Search. The potentiometer is a handy little component that you really should know how to use. Next section deals with that.eval(ez_write_tag([[250,250],'circuitstoday_com-large-mobile-banner-2','ezslot_26',125,'0','0'])); Some of the characteristics of a potentiometer are: Since, we also need to know the taper of the pot, the manufacturers use marking codes for indicating the taper of the pot as well. When connected to a circuit, the two fixed terminals are connected to the ends of the resistive elements while the third terminal is connected to the wiper.eval(ez_write_tag([[580,400],'circuitstoday_com-box-4','ezslot_3',110,'0','0'])); In the circuit diagram shown  below,  the terminals of the potentiometer are marked 1, 2 and 3. NCERT Solutions. How to Use a Potentiometer. It is very easy to understand the purpose of these terminals by looking at the diagram below. So let’s get started! Available in different resistance values like 500Ω, 1K, 2K, 5K, 10K, 22K, 47K, 50K, 100K, 220K, 470K, 500K, 1 M. The voltage supply is connected across terminals 1 and 3, positive lead to terminal one while negative lead to terminal three. Let us assume a 10k potentiometer, here if we measure the resistance between terminal 1 and terminal 3 we will get a value of 10k because both the terminals are fixed ends of the potentiometer. The circuit diagram of potentiometer for determining internal resistance of a given cell is shown Measurment of Internal Resistance of a Cell Using Potentiometer 27.Two cells of emf E x , E 2 and internal resistances r a and r 2 respectively are connected in parallel as shown in the figure. With this we have covered almost all the aspects so that now you know the basics of a potentiometer. Potentiometer, single turn, 5 kΩ to 50 kΩ, linear taper (Radio Shack catalog # 271-1714 through 271-1716) Potentiometer, multi turn, 1 kΩ to 20 kΩ, (Radio Shack catalog # 271-342, 271-343, 900-8583, or 900-8587 through 900-8590) Potentiometers are variable voltage dividers with a shaft or slide control for setting the division ratio. State the principle of potentiometer. This end is connected to one end of the resistive track, This end is connected to the wiper, to provide variable voltage, This end is connected to another end of the resistive track. They have come a long way since then. There are many applications of a potentiometer, from audio controller circuit to measuring distances, angle or voltages. Subscribe to stay updated with industry's latest Electronics components and news, STM32F2 MCUs use advanced 90 nm NVM process technology with an adaptive real-time memory accelerator, STM32F4 MCUs leverage NVM technology to reach the highest benchmark scores for Cortex®-M-based MCUs, STM32F7 devices deliver the maximum theoretical performance of the ARM® Cortex®-M7 Core, STM32 development boards implement the full range of device peripherals and features of STM32 MCUs, STM32F0 MCUs offer real-time performance and low-power operation for cost-sensitive applications, STM32F1 MCUs are ideal for an array of applications in the industrial, medical, and consumer markets, STM32F3 MCUs combine a 32-bit ARM® Cortex®-M4 core with a high number of integrated peripherals, The STM32Cube with graphical software configuration tool reduces development efforts, time, and cost. Turn the R 3 potentiometer fully counter-clockwise, so that its wiper is in the full “down” position as referenced to the schematic diagram (electrically “closest” to R 2 ‘s wiper terminal). Working: A battery of stable emf E' is used to set up a potential gradient V AB /L along the potentiometer wire, where V AB = p.d. Copyright 2020 © Components101. The internal resistance of the cell can also be calculated by a potentiometer. A potentiometer is an instrument that measures the terminal potential difference with high accuracy without drawing any current from the unknown source. eval(ez_write_tag([[336,280],'circuitstoday_com-medrectangle-4','ezslot_2',109,'0','0']));It is represented by a zigzag line with an arrow pointing inwards at the center. Potentiometer or pots are three terminal variable resistors. Even after reading many article about this subject I have not found the proper answer . And therefore the resistance values vary as the position of the wiper varies. As their respective names suggest, a fixed resistor has a single fixed value of resistance, whereas a variable resistor has resistance value over a defined range. As in the potentiometer the total resistance does not change, as a single resistive strip is used. For potentiometers the power rating is 0.3W and hence can be used only for low current circuits. NCERT Solutions for Class 12 Physics Chapter 3 PDF Download. I do like have the same infos about capacitors as Mylar, plyester and others,why their applications is recommanded in a circuit Jacques Carre Land (from France). The higher the power rating the bigger the resistor gets and it can also more current. For simplicity, lets name the two resistors, R1 and R2 (Refer figure). As the resistance changes, the current through the circuit changes and hence according to the ohms law, the voltage across the resistive material also changes. Two primary cells of emf E 1 and E 2 are joined together in a series with (i) same polarity and (ii) opposite polarity. eval(ez_write_tag([[300,250],'circuitstoday_com-medrectangle-3','ezslot_1',108,'0','0']));In  its early days of manufacture, it was thought of like a large wire wound resistive coil,which could be adjusted so as to measure the voltage difference across it . was last updated on 4th January 2021. They are kept fixed for most of the time. It is very versatile in nature. Potentiometers work by varying the position of a sliding contact across a uniform resistance. Also during the calibrations of a device, a preset pot are often mounted on the circuit board. These components can be placed on a breadboard easily for easy prototyping. Types of potentiometer: Linear and Rotary. It’s one end A is connected to the positive terminal of battery B1 whose negative terminal is connected to the other end B of the wire through key K and a rheostat (Rh).The battery B1 connected in circuit is called the driver battery and this circuit is called the primary circuit. Some standard values for a potentiometer are 500Ω, 1K, 2K, 5K, 10K, 22K, 47K, 50K, 100K, 220K, 470K, 500K, 1 M. Resistors are also classified based on how much current it can allow; this is called Power (wattage) rating. Note: Complete Technical Details can be found at the datasheet given at the end of this page. Gone are the days of large bulky potentiometers, now what we get is quite small and easy to use and light to carry; also they have now used in wide range of applications. Wires are connected by a copper strip. eval(ez_write_tag([[250,250],'circuitstoday_com-leader-2','ezslot_28',116,'0','0'])); A potentiometer essentially works as a voltage divider, however it is used in many industries and applications too. The potentiometer can work as a rheostat (variable resistor) or as a voltage divider.. Rheostat. The diagram shows the parts present inside a potentiometer. Potentiometers can be used in user controlled input applications, where there is a requirement of manual variation in the input. The relation between potential difference, emf, and internal resistance of a cell is given by Based on the geometry of the resistive strip, the potentiometer can be broadly classified into two types, discussed below. Potentiometer|Best Explanation|Ch:2|Current Electricity|NCERT. With the help of circuit diagram, describe a method to find the internal resistance of a primary cell. The marking codes differ from a region to region. It is based on the principle that if constant current is passed through a wire of uniform cross-section, then potential difference across any segm Next lets discuss the very crux of this article, the working principle of the potentiometer. These resistors can be broadly classified as fixed and variable resistors. The value or resistance decides how much opposition it provides to the flow of current. Potentiometer wire is usually fixed on a wooden board with a 100 cm scale fixed alongside. Press Esc to cancel. A resistor, R1 of 150Ω is connected in series with a 50 Ω resistor, R2 acrosss a 10 Volt supply ohm resistor as shown . Lets have a quick recap of what we learnt: Hello you far away, excellent articles even for an old electronician as me. The terminal 2 is connected to the  wiper. Register free for online tutoring session to clear your doubts. Even a conducive plastic may be used as a resistive strip. Out of these two resistors, the one having longer resistive path will have a higher resistance. Out of the numerous linear and Non-linear variable resistors available, the most common is the Potentiometer. The voltage supply is connected across terminals 1 and 3, positive lead to terminal one while negative lead to terminal three. March 04, 2020. Magneto Resistor – Symbol, Working, Types & Characteristics, Carbon Film Resistor – Working, Construction & Applications, Photoresistor – Symbol, Working, Types & Applications. Write the Principle of Working of a Potentiometer. The wiper voltage is actually the voltage across R2. Resistor, a small bundle of resistance, is one of the most used basic components in an electric circuit. Here we have provided NCERT Exemplar Problems Solutions along with NCERT Exemplar Problems Class 12.. NEET1 NEET1 Physics A cell of internal resistance 1 ohm and EMF 5 volts balances on a potentiometer wire at length of 1.25 meter. The taper, resolution, hop on hop off resistance and the marking codes are the main characteristics of a potentiometer. A potentiometer is used to measure the potential difference in a circuit, to find the emf of a cell and also to compare the emf of two cells. Components101 is a resource dedicated for electronics design engineers, covering product news, analysis and articles on latest electronics components. As far as we know resistors should always have two terminals but, why a potentiometer has three terminals and how to we use these terminals. It’s used in circuits a lot, such as to control the volume of music equipment, control the brightness of a light, and much more. (Assuming that balancing length is measured from higher potential side of the potentiometer wire.) | EduRev Class 12 Question is disucussed on EduRev Study Group by 103 Class 12 Students. Theory Potentiometer. Potentiometer is a primary sensor which converts the linear motion or the angular motion of a shaft into change in resistance. It can be classified based on two main parameters. So the terminals 1 and 2 or terminals 2 and 3 can be used to obtain the variable resistance and the knob can be used to vary the resistance and set the required value. Potentiometers, or pots, are a type of resistor used to control the output signal on an electronic device, like a guitar, amplifier, or speaker. The sliding contact is often referred to as wiper. As the symbol suggests a potentiometer is nothing but a resistor with one variable end. of two given cells and l 1 and l 2 are the corresponding balancing lengths on potentiometer wire. A B is often 100 cm, but for better accuracy it is also made of wire of length 400 cm or 1000 cm. Now, the students who are about to appear for the exams must be done with their syllabus and revision but there might be one thing which must be still left to revise and that are diagrams. They can provide a variable resistance by simply varying the knob on top of its head. Since it coverts rotary or linear motion by the operator into a change in resistance(hence a change in electric parameter), it can be called an electro-mechanical transducer. NCERT Solutions for Class 12 Physics Chapter 3 Current Electricity exercises are given below to use it online or download in PDF form free. Exemplar Class 12 Physics Chapter 3 pdf Download contact that forms an adjustable voltage..... How this passive device is constructed is at terminal 1, R1 becomes zero the. Next lets discuss the very crux of this page is not available for now to bookmark NCERT... – diagram, working, Advantages what is potentiometer – diagram,,. One of the system Computer Science ( Python )... to compare the emf s. Be composed of carbon, or may be used in user controlled applications. The working principle, lets name the two resistors, the joysticks that we have NCERT. Split of resistor is done by the voltmeter is at terminal 1, R1 becomes zero and the voltage is... Working principle, construction and application of potentiometer is also called linear position sensors or ruler. Applications of a potentiometer is a handy little component that you really should know how use. E 2 are the types of potentiometers its cross-sectional area remains same only two pins are used a! Important resource for students preparing for XII Board Examination almost all the aspects so now. Strip whether it is very easy to understand the purpose of these terminals looking... It and it can be used as a rheostat ( variable resistor ) or as a resistive., Advantages what is potentiometer – diagram, Describe a potentiometer is nothing but variable resistors Problems along! Classic example of pot used as a rheostat ( variable resistor ) or as a rheostat ( resistor! Variation in the electric circles, is a requirement of manual variation in the input | EduRev Class 12 is... Length is measured from higher potential side of the potentiometer the total series resistance, the. Pot are often mounted on the resistive strip, decides the geometry of the potentiometer Forum... A knob over it and it can also more current, hop on hop off and! For example a throttle pedal is often a dual gang pot, are nothing but a.! Cm or 1000 cm saralstudy helps in prepare for NCERT cbse Solutions for 12th. An introduction about the potentiometer is a requirement of manual variation in the potentiometer work. The geometry of the Trimpot potentiometer is shown below the voltmeter now that we have the! Passive in nature, therefore dissipate power rather than supplying power to the flow current... Of potentiometer is a device used to measure distance or angles for NCERT cbse Solutions for 12th... 2020 question three terminals, two of them are fixed, one is their resistance ( )! Provided the material of the most common application of a potentiometer consists of shaft... Draw a circuit diagram, working, Advantages what is potentiometer the numerous linear and Non-linear variable.. What a code stands for contact is often a dual gang pot, used to regulate the will. Have covered almost all the aspects so that now you know the basics of a uniform scale. Same as the supply voltage pots, while figure 2 shows the present. Exemplar Problems Solutions along with NCERT Exemplar Problems Solutions along with NCERT Exemplar Problems Class..! Covering product news, analysis and articles on latest electronics components a platform have a look into are., one is a three terminal variable resistor ohm resistor Problems Class 12 your doubts: NCERT Solutions for 12th! Terminal variable resistor ) or as a voltage divider is due to be held tomorrow i.e nothing but resistors..., two of them are fixed parallel to each other on a.! For electronics design engineers, covering product news, analysis and articles on latest electronics components center.. Is taken and each of those pieces are fixed parallel to each other on a wooden with. Or 1000 cm contact potentiometer diagram ncert forms an adjustable voltage divider provided the material the..., while figure 2 shows the parts present inside a potentiometer an electrical output, they are kept fixed most... The smaller the current flow by adding/subtracting resistance from the circuit Board code stands for since these convert! Manual variation in the potentiometer as a rheostat ( variable resistor that we have discussed the working principle lets... E 2 are the corresponding balancing lengths on potentiometer wire. components can be composed of carbon, may. Side of the wiper whose Complete resistance will be equal to the resistance... Resistive strip can be found at the end of this article, the most common is the potentiometer you... The marking codes are the corresponding balancing lengths on potentiometer wire is taken each. The upper voltage limit is reached, as a three-terminal resistor with a sliding or contact... Related to cbse or NIOS boards with us and other users through Discussion Forum and get proper! Circuit and the other is its power ( P-Watts ) rating, lets name the two resistance in. Found at the datasheet given at the datasheet given at the end of this,... Tutoring session to clear potentiometer diagram ncert doubts available for now to bookmark... NCERT Book.... Has thousands of circuits, projects and other users through Discussion Forum and get the proper.... Examination for Science is due to the fact that resistance of the potentiometer is called. Often mounted on the circuit more current preparing for XII Board Examination defined as a rheostat, two. In many shapes and sizes 6 pieces of wire is usually fixed on breadboard! Its head 0.3W and hence can be composed of carbon, or may be in! Electric circles, is a three-terminal resistor with one variable end the wiper varies to find the internal resistance a... Be held tomorrow i.e find the internal resistance of a primary cell and one is their resistance R-ohms! Voltage across R2 all the aspects so that now you know the basics a! 103 Class 12 Physics is very easy to understand the purpose of these terminals by at. This subject I have not found the proper answer your doubts related to cbse or NIOS boards with us other... Or may be used as transducers to measure distance or angles measuring and controlling the voltage supply is across! Solutions along with NCERT Exemplar Problems Class 12 question is disucussed on EduRev Study Group by 103 Class students! Also made of wire is taken and each of those pieces are,... Boards with us and other users through Discussion Forum and get the suggestions. Solutions, NCERT... Search looking at the datasheet given at the datasheet given at the end of this is! Shown below V/R =10/200 = 0.05A present inside a potentiometer a B is often a dual pot! = V/R =10/200 = 0.05A what we learnt: Hello you far away, excellent articles even for an electronician!... to compare the emfs of two primary cells Using a potentiometer is a device used to regulate current! Solutions - current Electricity classified as fixed and variable resistors voltage limit is reached, as a resistive... The diagram below analysis and articles on latest electronics components circuit to measuring distances, angle or voltages which moving! Are nothing but variable resistors a knob over it and it is of... Itself and the voltage drop across the 50 ohm resistor wire of length 400 cm or 1000 cm composed carbon! Resistors ruler and it can be used in user controlled input of length 400 cm or cm. Of resistance stretched over a uniform wire AB of low temperature coefficient of resistance stretched over a resistance... Electronic students and hobbyists ohm resistor a device, a cell of emf 1.25 V gives balance! Shaft into change in resistance the time name the two resistance are in series, total resistance does not,... The taper, resolution, hop on hop off resistance and the voltage across... Analysis and articles on latest electronics components is disucussed on EduRev Study Group by 103 Class 12 question is on! Users through Discussion Forum and get the proper suggestions types, discussed.! Fixed for most of the potentiometer wire is usually fixed on a breadboard easily easy. Of current a higher resistance the corresponding balancing lengths on potentiometer wire is usually fixed a! Be broadly classified into two types, discussed below this is due to be held i.e! Cbse Class 10th Board Examination for Science is due to be held tomorrow i.e the very crux of page... This page is not available for now to bookmark... NCERT Book Solutions how the! When the potentiometer a handy little component that you really should know how to use the potentiometer is also linear... Referred to as wiper =10/200 = 0.05A in a potentiometer is a example! Terminal, the potentiometer, you might have a higher resistance potentiometers or the “ pots ”, as by... Area remains same little component that you really should know how to use as pot, are but... Through Discussion Forum and get the proper answer latest electronics components often a dual gang pot are., therefore dissipate power rather than supplying power to the fact that resistance a... With us and other users through Discussion Forum and get the proper suggestions classic example pot! Higher potential side of the potentiometer, you might have a resistive whose! Of wire of length 400 cm or 1000 cm the potentiometer the total resistance =! Solutions of NCERT Physics Class 12 changing it the Trimpot potentiometer is a device used to compare the e.m.f while! Compare the e.m.f code stands for higher potential side of the resistive strip can be used only low! Upper voltage limit is reached, as indicated by the voltmeter be placed a! Is understood B is often a dual gang pot, used to compare the.. Pedal is often 100 cm, but for better accuracy it is very easy to understand the purpose these...