When light shines onto the photoelectric switch sensor, the photosensitive component inside (typically a photodiode or a photoresistor) generates an electrical signal. The intensity of this signal depends on the intensity of the light. When an object blocks the light, the intensity of light received by the photosensitive component decreases, resulting in a change in the electrical signal. The photoelectric switch detects this change in the electrical signal and triggers corresponding actions or controls.

Photoelectric switches are commonly used in automatic control systems to detect the position, distance, or presence of objects. For example, they can be employed in automatic door controls, object counting, packaging machinery, automatic lighting systems, and more.