Potentiometer Wiring and Pinout: A Guide with Practical Examples

Author: David Marriott, Spectra Symbol CEO

Understanding potentiometers and their wiring might seem tricky at first, but once you understand the pinouts and diagram, it will make much more sense. Whether you’re dimming an LED, adjusting volume, or fine-tuning other electrical outputs, learning how to wire a potentiometer is a key skill to have. This guide will break down potentiometer wiring in a simple, step-by-step manner.

What type of Potentiometers will we be talking about?

The most common type of potentiometer is a Rotary Potentiometer, which is what we’ll be using for diagrams and examples in this article. However, other types of potentiometers with similar wiring structures are Linear Potentiometers, Digital Potentiometers, and Trimpots. In most cases, the technical wiring aspects will be the same.

Watch as I explain the Wiring and Pinout of a Potentiometer

Potentiometer Diagram and Pins

Before jumping into wiring, it’s important to understand the potentiometer diagram and its three pins:

Pin 1: Input voltage (V_in).
Pin 2: Output or “collector.” This pin provides the adjusted voltage (V_out).
Pin 3: Ground or an additional input/output, depending on the circuit.

Internally, a potentiometer contains a resistive track connected to Pin 1 and Pin 3. A movable arm (the “collector”) connects to Pin 2. By turning the knob, the arm slides along the resistive track, altering the resistance and the voltage output.

How to Wire a Potentiometer

Here are two common ways to wire a potentiometer:

1. Varying Resistance for LED Brightness

This method uses the potentiometer to adjust resistance in a circuit. For example, you can control the brightness of an LED:

Connect Pin 1to your power source (positive voltage).
Connect Pin 2to the LED’s positive terminal.
Connect the LED’s negative terminal to the circuit ground.

In this setup:

As you turn the knob, the resistance changes.
Higher resistance dims the LED, while lower resistance brightens it.

If you prefer tidier wiring, you can connect Pin 3 to Pin 1, but it doesn’t affect the functionality.

2. Voltage Divider for Proportional Output

The voltage divider setup splits an input voltage into a proportional output. This is ideal when you need precise control over an output voltage:

Connect Pin 1to your power source (V_in).
Connect Pin 3to the circuit ground.
Use Pin 2to extract the output voltage (V_out).

Here’s how it works:

The collector (Pin 2) divides the total resistance into two sections (R1 and R2).
By turning the potentiometer, you adjust the ratio of R1 and R2. This determines V_out based on the equation:

For example:

If the collector is at the top, R2 = 0, and V_out = 0.
If it’s at the bottom, R1 = 0, and V_out = V_in.
If it’s in the middle, V_out = 0.5 × V_in.

Tips for Successful Potentiometer Wiring

Double-check the pinout: Misidentifying pins can cause improper functionality.
Use resistors if needed: For sensitive components like LEDs, adding a fixed resistor can prevent damage.
Plan your circuit: Decide if you need a voltage divider or a simple resistance adjustment.

Applications of Potentiometers

Dimming LEDs
Volume control in audio devices
Tuning circuits in radios or amplifiers
Adjusting sensor thresholds in DIY projects

Conclusion

Wiring a potentiometer might seem intimidating at first, but once you understand its pins and internal workings, it becomes straightforward. Whether you’re creating a voltage divider or using it to control resistance, mastering these basics is a valuable skill for any electronics enthusiast. Now that you know how to wire a potentiometer, the possibilities for your projects are endless!

Do you have specific questions about potentiometer wiring, or want help with your next project? Let us know in the comments!