Photoelectric sensors are sensing devices that use light to detect the presence, absence, position, or movement of objects. They typically consist of a light emitter, such as an LED or laser, and a receiver that detects the reflected or interrupted light.

When an object enters the sensing area, it changes the amount of light reaching the receiver, causing the sensor to generate an electrical output signal.
Common Types

Through-beam: The emitter and receiver are placed opposite each other; an object is detected when it interrupts the light beam.
Retro-reflective: The sensor detects an object when it interrupts light reflected from a reflector.
Diffuse-reflective: The sensor detects light reflected directly from the object itself.

Applications

Photoelectric sensors are commonly used in industrial automation, conveyor systems, packaging machinery, object counting, position detection, robotics, and safety systems.

Key advantages: fast response, non-contact detection, long sensing distances, and reliable operation for a wide range of objects.