CDS Photo Resistor 16K to 1M from Tinkering Supplies
Photoresistors provide varying resistance depending on the amount of light reaching the device. They are commonly used as line following sensor and for light alarms. The resistance of this device varies between approximately 1M ohm in total darkness to between 16K and 33K ohm in bright light (10 Lux @ 2856 degrees K). This is a relatively small photoresistor with a diameter of 0.165" (about 3/16").