500K Rotary Potentiometer 20mm – Linear Taper Variable Resistor

A potentiometer is a three-terminal variable resistor designed to act as an adjustable voltage divider or rheostat. A movable wiper slides/rotates along a resistive element, changing the resistance between the wiper and either end terminal. This directly adjusts the output voltage or current in your circuit—ideal for calibration, user controls, and analog signal conditioning in Arduino, Raspberry Pi (via ADC), and other microcontroller projects.

Key Features ⭐

• Resistance range: Available in values from a few ohms to several megaohms
• Taper: Linear (B) for smooth, proportional adjustment
• 3-terminal design: two ends of the resistive track plus an adjustable wiper
• Voltage divider or rheostat operation for flexible use in analog circuits
• Perfect for electronics components prototyping, modules, sensor calibration, and UI controls
• Works seamlessly with Arduino analog inputs and with Raspberry Pi using an external ADC

Technical Overview 📐

When used as a voltage divider, connect the two end terminals across the supply and take the output from the wiper. The output voltage varies from near 0 V to near the supply, proportional to the wiper position. As a variable resistor (rheostat), use one end terminal and the wiper to obtain an adjustable resistance from near 0 Ω up to the rated value.
The “B” marking denotes a linear taper, meaning the output changes linearly with mechanical rotation/position—ideal for precise control and predictable response in microcontroller ADC readings.

Types of Potentiometers 🧭

• Rotary Potentiometers 🔄: Adjusted by turning a knob; widely used for volume controls, tuning, and general-purpose analog adjustments.
• Linear (Slider) Potentiometers ↔️: Adjusted along a straight track; common in mixers, faders, and position-sensing applications.

Applications ⚙️

• Volume control in audio equipment (amplifiers, mixers, headphone amps)
• Brightness/dimming for LEDs and LCD backlights
• Motor speed control for DC motor driver inputs
• Tuning and frequency adjustment in RF/oscillator circuits
• Position/angle sensing and calibration in mechatronics

Interfacing Tips for Arduino & Raspberry Pi 🛠️

• Arduino: Connect the ends to 5 V and GND (or 3.3 V and GND), and the wiper to an analog input (ADC). Ensure the potentiometer supply matches the board’s ADC reference.
• Raspberry Pi: Use an external ADC module (e.g., MCP3008). Power the pot from the ADC reference (typically 3.3 V) and feed the wiper to an ADC channel.
• For rheostat use, wire the wiper and one end terminal only; consider adding a fixed series resistor if you need to limit current.

A linear potentiometer is a reliable, versatile choice for analog controls, calibration, and signal scaling across a wide range of electronics components and microcontroller-based projects.