The 20mm EC11 Rotary Encoder is a compact incremental rotary input device commonly used for user interface control in embedded systems and electronic equipment. Unlike a traditional potentiometer, it provides digital pulse outputs that indicate rotational direction and step count, making it ideal for precise position tracking and menu navigation.

The EC11 features a 20 mm body diameter and typically includes an integrated push-button switch, allowing it to serve as both a rotational and selection input device. This makes it widely suitable for applications such as volume control, frequency tuning, parameter adjustment, and menu scrolling in microcontroller-based systems.

Key Features

Type: Incremental mechanical rotary encoder

Body Diameter: 20 mm

Output Signals: Two digital pulse outputs (A and B channels, quadrature)

Switch Function: Built-in momentary push-button (press-to-select)

Detents: Available in stepped (click) versions for tactile feedback

Operating Voltage: Typically 3.3 V or 5 V logic compatible

Mounting: Through-hole PCB mounting

Shaft Type: Knurled or D-type shaft (varies by model)

Working Principle

The EC11 encoder generates two square-wave signals (Channel A and Channel B) that are 90° out of phase (quadrature encoding). By monitoring the sequence of these signals, a microcontroller can determine:

Direction of rotation (clockwise or counterclockwise)

Number of rotational steps (position change)

Each detent corresponds to a specific number of pulses, allowing accurate digital control without analog drift.