Proximity Switch & Photo Sensor

Proximity sensors are different type like Inductive / Capacitive / Namur / Ultrasonic. When an application calls for detecting a metallic target that falls within an inch of the sensing surface, inductive proximity sensors are apt for the task. Capacitive proximity switches contain 4 main components: plate, oscillator, detection circuit and solid state switch. The sensor operates in a similar fashion to a simple capacitor. When the power is turned on, the oscillator detects the amount of capacitance between the external target and the metal plate in the sensor. Both Inductive and Capacitive Proximity can both be termed as NAMUR switches. NAMUR switches are designed to be used in hazardous locations with very low voltage requirements. Ultrasonic sensors (also known as transceivers when they both send and receive) work on a principle similar to radar or sonar which evaluate attributes of a target by interpreting the echoes from radio or sound waves respectively.