IEC 60306: Photoresistors — From Camera Exposure Meters to Streetlight Control

CdS Photoresistors — Simple, Reliable Sensors Where More Light Means Lower Resistance

IEC 60306-2:1969 specifies photoresistor requirements. CdS photoresistors exhibit light resistance (at 10 lux) only 1/100–1/1,000 of dark resistance — this simple, massive resistance change makes them ideal for streetlight control, flame detection, and camera exposure meters. Peak spectral response at 550–600 nm (yellow-green), closely matching human eye sensitivity.

TNLab — CdS photoresistors may be slow, but for streetlight control, they are more than adequate.