# What is Potentiometer: Definition and 105 Discussions

A potentiometer is a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider. If only two terminals are used, one end and the wiper, it acts as a variable resistor or rheostat.
The measuring instrument called a potentiometer is essentially a voltage divider used for measuring electric potential (voltage); the component is an implementation of the same principle, hence its name.
Potentiometers are commonly used to control electrical devices such as volume controls on audio equipment. Potentiometers operated by a mechanism can be used as position transducers, for example, in a joystick. Potentiometers are rarely used to directly control significant power (more than a watt), since the power dissipated in the potentiometer would be comparable to the power in the controlled load.

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1. ### To get potentiometer recommendation

Hi, folks I need a recommendation for a potentiometer. I have an old 8mm projector that uses a 8v 50w bulb. The bulb works off a simple on/off switch. I would like to insert a potentiometer inline between the transformer and bulb to vary the intensity of light the bulb generates. Even if I...
2. ### In what way does current flow through a potentiometer?

Above is a picture of a potentiometer with terminals A, B, and W. Does current always from from A to W or can current flow directly from A to B? Is there usually both? And what do they mean when they say a potentiometer is an effective "voltage divider"?
3. ### Question about potential and current in potentiometer circuit

Let say S is the balanced point so current flowing through galvanometer is zero. This is because the potential difference across PS is the same as potential difference across solar cell so no potential difference means no current flowing. My questions: 1) If I want to compare the potential at a...
4. ### Engineering Derivation of the error due to a finite load attached to a potentiometer

x = fraction of potentiometer connected to load Vp in parrallel with VL = x/(Rp/RL.x.(1-x) + 1) If RL = infinite, then Ro = x and Vo = x.Vs If RL = finite, then Ro = x/(Rp/RL.x.(1-x) + 1) and Vo = x.Vs/(Rp/RL.x.(1-x) + 1) Therefore error is x.Vs - x.Vs/(Rp/RL.x.(1-x) + 1) Trying to break the...
5. ### Balance length for a potentiometer circuit

Here is the question itself Here is my attempt at it Does 4cm look right? Any help would be great, thanks!
6. ### Calculating resistances via a potentiometer

Homework Statement Figure shows a potentiometer circuit for comparison of two resistances , the balance point with standard resistor R = 10 ohm , is found to be 58.3 , while that with unknown resistance X is 68.5 cm , determine the value of X . b) what might you do if you failed to find the...
7. ### Should I use a potentiometer or Quadrotor encoder?

Specifications: Measuring angle from -90 to + 90 degs. Low friction Low moment of inertia Requires high speed Accuracy about 1° degree. Needs to be durable, handle mechanical vibration I use a dc motor as an actuator, this is a custom built servo. This is a very small device, and the encoder...
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### Potentiometer electrical engineering question

Homework Statement The circuit of FIGURE 2 shows a 10 kΩ potentiometer with a 5 kΩ load. Determine the position of the slider on the ‘pot’ when the voltage across points ‘XX' is 3 V. Homework Equations The Attempt at a Solution I really don't know the right way to start this. If I'm being...
9. ### Potentiometer Circuit 1: Balancing the Current - Solving for Ix and Rx

1. problem statement, all variables and given/known data 1) What is the relationship between Ix and Rx ? 2) Prove that on varying resistance Rx , Ix reduces to zero . Homework EquationsThe Attempt at a Solution Assume resistance of Galvanometer is ##r## . Total resistance in middle branch...
10. ### Potentiometer alternatives

So a friend and I are building a power supply using buck converter. The buck converter is going to be using the adjustable version of the LM2678 switching controller that will regulate the output voltage by varying the duty cycle. The chip uses a voltage divider connected to the output voltage...
11. ### Potentiometer nulling voltages in a circuit

this is the potentiometer and the emf of cell E2 is unknown. now to know the emf just finding the null point of the galvanometer is enough. its because at that given length the potentiometer has the same potential as the cell. but why are they equal at null point? Sent from my Micromax E311...
12. ### MOSFET or Rheostat or Potentiometer pros and cons?

Preface: I'm a chemical engineering undergraduate student but as small-time and noob electrical engineering hobbyist. I really only have minimal experience in circuitry and the like. I want to build a series of electromagnets with a variable their strength in order to levitate an opposing...
13. ### Potentiometer and EMFs with internal resistance

Homework Statement In a potentiometer 99cm of wire of resistance 99ohms is connected with a battery of 50V and 1ohm internal resistance.Find emf of battery giving zero deflection for a length of 13cm. Homework Equations Sadly,the formula I know is only for ideal emfs,which states that: If two...
14. ### Potential Gradient of potentiometer wire

Homework Statement The resistivity of a potentiometer wire is (40×10^-8) ohm-m and the area of cross section is (8×10^-6)m^2.If 0.2 amp current is flowing through the wire,then the potential gradient will be?? Homework Equations 1.Resistance=[(Resisitvity)×(Length)]/(Cross-sectional area)...
15. ### CV redox peaks and Gamry Potentiometer

I'm using Gamry Potentiometer for taking CV measurements for finding the appropriate voltage values for oxidation/reduction peaks and Echem Analyst for analyzing. CV measurements has performed on liquid electrolyte in order to find if working electrode accept Li ions. My question is about...
16. ### Detect increasing or decreasing pot output

I want to detect whether potentiometer output voltage is increasing or decreasing and convert this to a digital signal. the circuit must be able to sense tiny voltage changes (order of 10mV) and with high speed. all I am interested is if Vout increases or decreases not by how much increasing V...
17. ### Can a MOSFET be used to replace a mechanical potentiometer in a PWM circuit?

Hello, I've been wanted to make a PWM module for a DC motor for a micro controller powered quadcopter. Now it might be easier to just punch the code for PWM, however I would like a voltage of more than 5 volts on the motor. That wouldn't be a problem to adjust the components and source. The...
18. ### Experiment using a potentiometer

Homework Statement In this experiment, we're trying to study the characteristics of a light bulb. Here are the steps outlined for us: 1. Use a potentiometer to vary the voltage across the bulb measured by the voltmeter V. Collect data of V-values and corresponding I'-values from the ammeter...
19. ### Making a reliable potentiometer

Long story short : I need a good solid semiconductor material besides pencil lead I can't find any potentiometers that I can insert my own shaft into so I decided to try to make my own. The shaft is about 0.25" in diameter so it's not something big. Anyways, I know I can use pencil lead as a...
20. ### Selecting a Potentiometer

Hi. Please could anyone advise me on selecting an appropriate Ohms and and Watts range for a Potentiometer. This is to energize the speed controller on a car heater blower motor that has lost its supply from the ECU pompously known as the Climate Control ! The blower motor is 12 Volt and fused...
21. ### A light-dimmer switch with a potentiometer

Homework Statement Some light-dimmer switches use a variable resistor as shown in figure. The slide moves from position x = 0 to x = 1, and the resistance up to slide position x is proportional to x (the total resistance is Rpot = 100Ω at x = 1). What is the power expended in the light bulb if...
22. ### What constant p.d. should be used in a potentiometer?

Homework Statement I am trying to use a slide wire potentiometer and a galvanometer to find the electromotive force of an unknown cell. I have heard that the balance point at which the galvanometer needle has zero deflection should be towards the centre of the slide wire as this reduces...
23. ### Amplify Position Sensor Circuit

Hi everyone, I'm working on a college project this year about mountain bike suspension damping. By trade I'm a mechanical engineer however, I'm required to construct a simple sensor circuit to monitor the performance of the damper I am making. Forgive me if my wording or logic is not quite...

Homework Statement This isn't really a homework question, but I was fiddling around on the virtual electronics lab at 123D circuits to familiarize myself with the various electrical components used in making circuits and just to familiarize myself with building electronics in general since I'm...
25. ### Potentiometer values and ratings

Hello everyone. I need to replace this potentiometer. I an not sure how to comprehend these values. Also, I don't understand why there is a resistor in parallel. What is the wattage rating and is it possible to get a potentiometer that can operate correctly without that resistor?
26. ### Engineering Linear potentiometer in a circuit problem

Homework Statement The total resistance for the linear potentiometer (R1) is 470 Ohms, and its length is 50mm. Calculate the distance x of the slider from the left edge of the potentiometer for which the output voltage (V out) is 0 V. Homework Equations Vout = Vin * (R1/(R2+R1)) The Attempt...
27. ### Finding Potential Difference in a Potentiometer Circuit

Homework Statement Homework EquationsThe Attempt at a Solution The answer is B. But I thought E1 needs to be be known first in order to find E2... And why not the resistance of the wire XY? E1/ Rxy = E2/ Rxt Then, in order to find Rxt, we need E1, Rxy and E2?
28. ### Solving potentiometer problem with addition of resistor

Homework Statement The emf of a battery A is balanced by a length of 75 cm on a potentiometer wire. The emf of a standard cell, 1.02V, is balanced by a length of 50 cm. What is the emf of A? Calculate the new balance length if A has an internal resistance of 2 Ω and a resistor of 8 Ω is joined...
29. ### Measurement of unknown resistance using potentiometer

[Mentor's Note: Thread moved to homework forums from another forum] Figure shows a potentiometer circuit for comparison of two resistances. The balance point with a standard resistor R = 10.0 Ω is found to be 58.3 cm, while that with the unknown resistance X is 68.5 cm. Determine the value of...
30. ### 24VDC 0,570 Amp pump controller

Hi,So let's start with this, I don't have a lot of electronics circuits background and not really an idea on how to build an electronic circuit. Ok, now the problem, at my job I am in need of controlling a 24VDC 0,570 Amp pump with a pot, preferably one with a "preset" in it so that the values...
31. ### Understanding Potentiometers in Circuit Diagrams

Homework Statement Homework Equations No equations required The Attempt at a Solution The correct choice is A. I know that a potentiometer provides some of its resistance of its total resistance and the other part is not contributed. Current flows from the + of the battery and re-enters the...
32. ### Speed limitations of pot & arduino for angle measurement?

If I am using a continuous rotation potentiometer on a pulley, and I want to use an Arduino to convert this reading into an angle as part of an angle control system, then what are the limitations for how fast the pulley can turn? Specifically, if the pulley is turning at 450RPM, will a...
33. ### Potentiometer Problem: 3V Battery, 100cm Sliding Wire, and 60cm Voltmeter

Homework Statement A 3-V battery of internal resistance 1Ω is joined to a sliding wire of length 100 cm and resistance 5 Ω . A voltmeter , which takes negligible current , is connected across 60 cm length of the wire . (a) What is the reading of the voltmeter ? (b) If the reistance of the...
34. ### Measuring resistance using potentiometer

Homework Statement Homework Equations For R, current I=E/R and for X, I=E/X... both are separate cases. The Attempt at a Solution [/B] Why does the balancing change? The potential difference across each resistor is E Itself right? I tried by assuming an arbitary internal resistance r...
35. ### Potentiometer position problem

Homework Statement The problem that is that of a loaded potentiometer and the position on the slider. The question is that a 10k Ohm potentiometer is connected across a 9 volt dc supply. Across the bottom part of the POT a 5k Ohm resistive load is connected which has 3 volts developed across...
36. ### Potentiometer and galvanometer experiment

Homework Statement Zero deflection in galvanometer Homework Equations If potential difference across between two points between which galvanometer is kept is zero galvanometer shows zero deflection. The Attempt at a Solution But my doubt starts from this video at 3:33 to 3:44 teacher says...
37. ### Wirewound Potentiometer question

Homework Statement A Wirewound potentiometer having 300 turns is to be used in the following system (see atached question file) Homework Equations See attached coursework file The Attempt at a Solution Unsure where to begin. I have converted the circuit in the attached file to a Thévenin...
38. ### What Determines the Current Flow in a Potentiometer?

Based on above figure, balanced point is point N. If the jockey is put at the left or right of point N, there will be current flowing through the galvanometer. On my note, when jockey is at point L, VAL < E (where E is potential difference of cell at lower part of the circuit). When the jockey...
39. ### Transfer Function of Potentiometer

Hey guys, I am new to this forum. I am working on a problem analyzing a potentiometer accelerometer. For the first part, I need to find the transfer function of the potentiometer. known: y=x2-x1 dynamic system: y,x1 For the mechanical aspect of the problem, I found that the transfer function...
40. ### Constant current source using digital potentiometer

Hello Everyone, Best wishes Am new to this forum. Please need a brand new suggestion for digitally controlled constant current source. I am designing this circuit for Plating thickness measurement. I have tried a several circuits based on Analog pot but would be helpful if i get with Digital...
41. ### Potentiometer circuit for comparison of two resistances

Question : Figure shows a potentiometer circuit for comparison of two resistances. The balance point with a standard resistor R = 10.0 Ω is found to be 58.3 cm, while that with the unknown resistance X is 68.5 cm. Determine the value of X. Isn't the question wrong? I've searched for it...
42. ### Finding the ratio of the emfs of two cells by a potentiometer

I don't have a clear perception of how the following question is answered: "Two primary cells of emfs E1 and E2 respectively are joined in series with (i) the same polarity, and (ii) opposite polarities. The combination is connected through a galvanometer and a jockey to a potentiometer. The...
43. ### MATLAB Potentiometer modeling by Matlab

I can't model the potentiometer in speed governor control system by MATLAB even I know the input of it is pu and the output is voltage but when I run the program it has an error occur I want to see what wrong it is. Help me please
44. ### Can I use a ordinary 1K ohm potentiometer to convert 12V to 5V?

I have a 1K ohm potentiometer.(datasheet is attached below). My aim is to convert 12V to 5V,which I would then apply to power the Arduino microcontroller. I'm not quite sure if I CAN use the potentiometer I have ie T93 YA 1K 1035 to do this conversion. The datasheet says that the maximum...
45. ### Using Potentiometer to find balancing emf.

According to my book, if we connect a high resistance in series to the secondary cell (whose emf is to be balanced) , connect this whole apparatus to a potentiometer with an auxiliary Emf and find the null point . It's written that even after removing the Hugh resistance the null point comes...
46. ### Calculating Galvanometer Current in Potentiometer Circuit | 2.0V Driver Cell

Hi, I have a question which goes like this: There is a potentiometer consisting of a 2.0V driver cell, slide wire and galvanometer with a 2.0kΩ series resistor used to find the emf of a Daniel cell. The emf of the Daniel cell is found to be 1.08 V. Now, approximately what current flows...
47. ### Potentiometer question: Finding Slider Position for Voltage Division Circuit

Homework Statement A circuit shows a 10kΩ Pot with a 5k Ω load. Determine the position of the slider on the pot when the voltage across the 5kΩ load is 3 volts. The input voltage is 9 volts. Homework Equations The Attempt at a Solution Input voltage = 9 volts. Output voltage = 3...
48. ### Can you help identify home-made potentiometer components?

Can you help identify "home-made" potentiometer components? Hi all, I work well with my hands, but am not very applied with electronic gadgetry as to what exactly the components in the pictures are. I know there are transistors, resistors an integrated circuit and etc. I was wondering if...
49. ### Engineering DC Circuit Analysis with a Potentiometer

I've been able to get all of the problems up to this point, but I have never seen a problem like this before, so here it goes: 9. Below is shown a simple resistive current source. The resistive load is represented by a 10 kΩ potentiometer. What is the current through the resistive load over...
50. ### How to control motor using ESC, Ardiuno, and a potentiometer

So I want to build an electric longboard. I have access to pretty much any machining equipment but don't have much knowledge on the electrical side of things. I know I will need a LiPo battery (I am aware of the dangers of them), and an electronic speed controller (ESC) hooked up to the motor. I...