Encoders installed on geared motors can be mainly classified according to two dimensions: working principle and output signal type. For common DC geared motors, Hall encoders and incremental encoders are the most widely used combination.
Classification by Working Principle
This depends on the technology by which the encoder detects position and speed.
· Hall Encoder (Magnetic): Detects position and speed using changes in a magnetic field. It is low-cost, vibration-resistant, dustproof, and waterproof, and is very common in miniature geared motors such as N20.
· Photoelectric Encoder: Detects position and speed using the principle of light transmission through a grating. It has extremely high accuracy, but is slightly more expensive and has stricter requirements for the working environment.
· Inductive Encoder: Detects position and speed using the principle of electromagnetic induction. It combines high accuracy with strong environmental adaptability and is commonly used in demanding industrial applications.
Classification by Output Signal Type
This determines how the encoder tells the controller the current position.
· Incremental Encoder: Outputs two square wave pulses, A and B, with a 90° phase difference (some also have a Z phase for zeroing). It only provides position change information, has a simple structure, and is the mainstream feedback solution for everyday DIY projects and robotic vehicles.
• Absolute encoder: Outputs a unique digital code corresponding to each position. Its biggest advantage is that it does not lose position after power failure and does not require “zeroing.” It is mainly used in servo motors or high-end industrial lines.
For everyday robotic vehicles or DIY projects, the most commonly encountered type is the incremental Hall encoder.
Post time: Feb-23-2026