An NPN Photoelectric Switch is a type of photosensor used in automation and control systems to detect the presence, absence, or distance of an object using light—typically infrared or visible red.
- Output Type: NPN (sinking)
- Detection Modes:
- Through-beam – emitter and receiver are separate (longest range)
- Retroreflective – uses a reflector
- Diffuse – object reflects the light to the sensor
- Supply Voltage: Typically DC 10–30V
- Detection Distance: Ranges from a few mm to several meters
- Output: Transistor output (open collector NPN)
- Response Time: Fast switching—often <1 ms
