How to Wire a Potentiometer: Complete Guide

A potentiometer is one of the most common components in electronics, but the wiring confuses a lot of beginners because it has three terminals instead of two, and the same part can be wired two completely different ways depending on what you want it to do. Whether you are building a guitar volume control, reading a knob position with an Arduino, or wiring a lamp dimmer, the underlying part is the same -- what changes is which terminals you connect.

In this guide, we cover the three terminals, the two wiring modes (voltage divider and rheostat), linear vs. audio taper, two worked examples with exact wiring, a step-by-step procedure, a wire/terminal reference table, and a troubleshooting table for the problems that come up most often.

What Is a Potentiometer?

A potentiometer ("pot" for short) is a variable resistor with three terminals. Inside the case is a resistive track -- a strip or ring of resistive material -- with a fixed value measured end to end, such as 10k or 500k ohms. A wiper contact slides or rotates along that track as you turn the knob or move the slider, tapping off a variable point: two fixed ends and one moving contact.

Potentiometers show up in volume knobs, tone controls, dimmer switches, joysticks, and as a simple way to feed an analog voltage into a microcontroller's ADC (analog-to-digital converter) pin. The wiring is simple once you understand each terminal, but getting the mode wrong -- voltage divider versus rheostat -- is the most common source of confusion.

The Three Terminals Explained

Every standard potentiometer has three terminals, usually numbered 1, 2, and 3 in the datasheet:

• Terminal 1 (outer): One end of the resistive track. A fixed point -- always connected to one end of the track regardless of wiper position.
• Terminal 2 (center/wiper): The moving contact that physically slides or rotates along the track. Its resistance to Terminal 1 and to Terminal 3 changes continuously as you turn the shaft, and the two values always add up to the pot's total rated resistance.
• Terminal 3 (outer): The other end of the resistive track, a fixed point opposite Terminal 1.

Turn the shaft fully in one direction and the wiper sits near Terminal 1, so resistance from Terminal 1 to the wiper is close to zero and resistance from the wiper to Terminal 3 is close to the full rated value. Turn it fully the other way and the relationship flips. At the midpoint of rotation on a linear taper pot, the wiper splits the resistance close to evenly between the two outer terminals.

Terminal numbering is not universal -- some panel pots reverse the order, and some breadboard pots print no numbers at all. What is universal is the physical layout: two outer terminals at the fixed ends of the track, and the center terminal always the wiper.

Voltage Divider Mode (Standard Wiring)

Voltage divider mode is how a potentiometer is normally wired to read position or control volume -- it is what people usually mean by "wire a potentiometer." All three terminals are used.

You apply a voltage across the two outer terminals -- for example, 5V to Terminal 1 and ground (0V) to Terminal 3. That voltage drops evenly across the resistive track. The wiper (Terminal 2) then outputs a variable voltage somewhere between 0V and the applied voltage, depending on where it sits. Turn the wiper toward the 5V end and the output rises toward 5V; turn it toward ground and the output falls toward 0V.

This is exactly how a microcontroller reads a knob's position: the wiper output feeds an analog input pin, and the ADC converts that voltage into a number. It is also how an audio volume control works: a signal is applied across the two outer terminals relative to ground, and the wiper -- now the output tap -- passes a proportional slice of that signal to the next stage.

The output voltage at the wiper is proportional to the wiper's physical position, not to the current flowing through the circuit. That makes voltage divider mode the right choice any time you need a variable voltage output rather than a variable resistance.

Rheostat Mode

Rheostat mode uses only two of the three terminals: one outer terminal plus the wiper. The pot then behaves as a simple two-terminal variable resistor in series with the circuit, controlling current flow rather than producing a proportional output voltage. There are two common ways to wire it:

• Two-terminal method: Connect one outer terminal and the wiper to the circuit, leaving the other outer terminal unconnected. This works, but over time dust or wear on the unused track can cause noise, since the wiper alone carries current.
• Jumpered method (more reliable): Connect one outer terminal and the wiper as before, but also run a short jumper between the wiper and the unused outer terminal. This ties them together electrically, so if the wiper contact gets dirty, current can still flow through the solid connection at that end. This is standard practice in dimmer circuits where long-term reliability matters.

Rheostat mode is common in simple lamp dimmers and motor speed controls, where you need to limit current directly rather than tap off a proportional voltage. It is less common in modern electronics than voltage divider mode, since it wastes power as heat and does not scale cleanly to digital circuits.

Linear Taper vs. Audio (Logarithmic) Taper

"Taper" describes how the resistance between the wiper and an outer terminal changes as you rotate the shaft from one end to the other. Choosing the wrong taper for the application is a common mistake.

• Linear taper (marked "B", e.g. B10K): Resistance changes evenly and proportionally with rotation -- 25% of the way through the sweep gives roughly 25% of the total resistance. This predictable, straight-line relationship suits general-purpose electronics, sensors, and microcontroller analog inputs.
• Audio taper / logarithmic taper (marked "A", e.g. A500K): Resistance changes non-linearly, matched to how the human ear perceives loudness. Hearing works on a roughly logarithmic scale, so a linear-taper volume pot feels like almost all the volume change happens in the first quarter-turn. An audio taper pot compensates so perceived loudness increases at a steady rate across the full sweep.

Use linear taper for sensors, position feedback, microcontroller inputs, and most non-audio control applications. Use audio taper specifically for volume controls where the human ear is the final judge of the control feel. A linear pot on a volume knob is not dangerous, but it will feel wrong -- most of the useful range gets crammed into a small arc near one end.

Worked Example 1: Audio Volume Control Wiring

This example covers a typical audio-taper potentiometer wired as a volume control, the kind used in guitar electronics and line-level audio gear -- commonly 250k (single-coil pickups) or 500k (humbuckers), always audio taper for a volume application. This is voltage divider mode applied to an audio signal instead of a DC control voltage:

1. Signal in connects to one outer terminal (commonly Terminal 3, though guitar wiring diagrams vary by manufacturer -- check the diagram for your specific pot or pickup).
2. Ground connects to the other outer terminal (commonly Terminal 1).
3. Wiper (Terminal 2) connects to the output, which feeds the next stage -- the output jack, a tone control, or an amplifier input.

Turning the knob toward the signal-in terminal passes more of the signal through to the wiper (higher volume); turning it toward ground shunts more of the signal away before it reaches the wiper (lower volume, down to fully off). If the volume feels "backwards," the two outer terminals are most likely swapped from what the diagram intended -- a wiring orientation issue, not a fault, fixed by swapping the two outer-terminal connections.

Worked Example 2: Arduino Analog Input Wiring

This example covers a 10k linear-taper potentiometer wired to read shaft position on an Arduino analog input -- a standard way to add a manual control knob to a project.

1. One outer terminal connects to the Arduino's 5V pin.
2. The other outer terminal connects to the Arduino's GND pin.
3. The wiper (center terminal) connects to an analog input pin, such as A0.

The pot forms a voltage divider between 5V and ground, and the wiper outputs a voltage somewhere between 0V and 5V depending on shaft position. The Arduino's built-in ADC on most boards (Uno, Nano, Mega) is a 10-bit converter, reading that analog voltage as an integer from 0 to 1023, where 0 corresponds to 0V and 1023 corresponds to 5V.

The math is directly proportional -- divide the wiper voltage by 5V and multiply by 1023 to get the expected reading:

• Wiper fully toward the 5V terminal: output close to 5V, ADC reading close to 1023.
• Wiper at midpoint of rotation: output close to 2.5V, ADC reading close to 512.
• Wiper fully toward the GND terminal: output close to 0V, ADC reading close to 0.

Because this is a linear taper pot, that relationship holds evenly across the entire rotation, unlike an audio taper pot, which would skew the reading toward one end of the sweep.

Step-by-Step Wiring Procedure

1. Identify the taper you need. Linear for sensors, position feedback, and microcontroller inputs. Audio/logarithmic for volume controls.
2. Identify the three terminals, using the datasheet or the numbers molded into the case. If unmarked, use a multimeter on resistance: the two terminals with a fixed resistance close to the pot's rated value are the outer terminals, and the third is the wiper.
3. Decide on the wiring mode. Voltage divider (all three terminals) for a variable voltage output or audio signal. Rheostat (one outer terminal plus wiper) for a simple variable resistance in series with a circuit.
4. For voltage divider mode: connect your supply voltage (or signal source) to one outer terminal, ground (or return path) to the other, and route the wiper to your output -- an ADC input, an amplifier stage, or wherever the variable signal needs to go.
5. For rheostat mode: connect one outer terminal and the wiper in series with the circuit, and either leave the far outer terminal unconnected or jumper it to the wiper for better reliability.
6. Double-check terminal orientation before powering up -- swapped outer terminals reverse the control direction without causing damage.
7. Power up and test. Sweep the control through its full range and confirm the output behaves smoothly, with no dead spots or crackling, then secure the mounting nut or bracket.

Wire/Terminal Reference Table

Troubleshooting Table

Common Mistakes

• Using linear taper where audio taper belongs. A linear-taper pot on a volume control works electrically, but almost all the perceived volume change bunches up near one end of rotation, making fine adjustment difficult through most of the sweep.
• Leaving the wiper floating carelessly in rheostat mode. A floating unused outer terminal is a valid wiring, but skipping the jumper-to-wiper option on a pot that will see years of dust and use trades long-term reliability for a slightly simpler job.
• Not tracking which outer terminal is Terminal 1 vs. Terminal 3. The two outer terminals are electrically symmetric, so swapping them does not break the circuit, but it does reverse the direction the control "feels" like it works in. Keep orientation consistent with your diagram, especially on multi-pot projects like a mixer, so every control turns the same direction for "more."
• Assuming all pots number terminals the same way. Numbering is not standardized across manufacturers, and outer-terminal order can differ between panel, PCB-mount, and trimmer pots. Verify with a multimeter or datasheet rather than assuming.
• Forgetting that resistance across the two outer terminals never changes. Only the wiper's resistance to each outer terminal changes as you turn the shaft; a shifting value across the outer terminals themselves means the track is damaged.
• Ignoring the pot's power rating in rheostat mode. The pot dissipates power as heat in this mode, and higher current through a low-wattage pot can overheat the track.

Safety Notes

Most potentiometer wiring -- Arduino projects, guitar electronics, small audio gear -- involves low-voltage circuits (5V, 9V, or similar) with minimal shock risk, and you can generally work on these live if needed for testing.

That changes when a potentiometer is used in a mains-adjacent context, such as a lamp dimmer or an appliance speed control wired directly into household AC power. In that case, treat it like any other mains wiring project:

• De-energize the circuit at the breaker or by unplugging the device before wiring a dimmer or speed control.
• Verify the circuit is dead with a non-contact voltage tester before touching any terminal.
• Use a pot rated for mains-adjacent duty, not a low-voltage electronics pot pulled from a hobby kit.
• Enclose all mains-side connections in an appropriate housing or junction box.
• If you are not confident working with household wiring, hire a licensed electrician.

Key Takeaways

• A potentiometer has three terminals: two outer terminals at the fixed ends of the resistive track, and one center wiper terminal that taps a variable point as you turn or slide it.
• Voltage divider mode uses all three terminals -- supply across the two outer terminals, variable output from the wiper -- and is the standard wiring for volume controls and analog sensing.
• Rheostat mode uses only one outer terminal plus the wiper; jumpering the wiper to the unused outer terminal improves long-term reliability over leaving it floating.
• Linear taper changes resistance evenly with rotation and suits sensors and microcontroller inputs; audio/logarithmic taper matches human hearing and suits volume controls.
• On an Arduino, a 10k linear pot wired 5V-wiper-GND feeds a 10-bit ADC that reads 0 to 1023 in direct proportion to the 0V-to-5V wiper voltage.
• Swapped outer terminals reverse the control direction but do not damage anything.
• Always verify unmarked terminals with a multimeter rather than assuming a numbering convention.
• De-energize and verify dead before wiring a potentiometer used in a mains-adjacent context like a lamp dimmer.

Frequently asked questions

What are the 3 terminals on a potentiometer?

A potentiometer has two outer terminals (terminals 1 and 3) connected to the fixed ends of the resistive track, and one center terminal (terminal 2) called the wiper. The wiper physically slides or rotates along the track, tapping off a variable resistance or voltage as you turn the knob or move the slider.

How do you wire a potentiometer as a voltage divider?

Apply your supply voltage to one outer terminal and ground to the other outer terminal. The wiper (center terminal) then outputs a variable voltage between 0V and the supply voltage depending on its position. This is the standard wiring for volume controls and for reading a knob position with a microcontroller's analog input.

What is the difference between rheostat and potentiometer wiring?

Potentiometer (voltage divider) wiring uses all three terminals to output a variable voltage proportional to wiper position. Rheostat wiring uses only one outer terminal plus the wiper, so the part acts as a simple two-terminal variable resistor controlling current in series with a circuit, not a proportional voltage output.

Should I use a linear or audio taper potentiometer for volume?

Use audio (logarithmic) taper for volume controls. Human hearing perceives loudness logarithmically, so an audio taper pot spreads the perceived volume change evenly across the full rotation. A linear taper pot on a volume control bunches most of the perceived change into a small arc near one end.

How does a potentiometer connect to an Arduino?

Connect one outer terminal to 5V, the other outer terminal to GND, and the wiper (center terminal) to an analog input pin like A0. The Arduino's 10-bit ADC reads the wiper voltage as a value from 0 to 1023, proportional to 0V through 5V, letting you read the knob's position in code.

Why does my potentiometer volume control feel backwards?

This happens when the two outer terminals are swapped relative to the intended wiring diagram, reversing which direction increases the signal passed to the wiper. It is not a fault and causes no damage. Fix it by swapping the two outer-terminal connections so the sweep direction matches what you expect.

Interactive diagrams for this guide

• Potentiometer Wiring Diagram
• Potentiometer Circuit Diagram
• Potentiometer Pin Diagram
• B10k Potentiometer Pinout
• Arduino Wiring Diagram
• Arduino Circuit Diagram
• Arduino Uno Circuit Diagram
• Arduino Uno Board Diagram
• 2 Volume 1 Tone Wiring
• Guitar Wiring Diagrams 2 Pickups 1 Volume 1 Tone