Photo resistors, also known as light dependent resistors (LDR), are light sensitive devices most often used to indicate the presence or absence of light, or to measure the light intensity.
In the dark, their resistance is very high, sometimes up to 2MΩ, but when the LDR sensor is exposed to light, the resistance drops dramatically, even down to a few ohms, depending on the light intensity.
LDRs have a sensitivity that varies with the wavelength of the light applied and are nonlinear devices.
They are used in many applications but are sometimes made obsolete by other devices such as photodiodes and phototransistors.
Manufacturer: Tayda Electronics
Manufacturer Part No: 5528
Product Category: Optical Sensor
Datasheet: Click Here
Product Type: CDS Photo Conductive Cell
Package: RADIAL 5mm
Spectral peak (nm): 540nm
Maximum Voltage: 150VDC
Photo Resistance at 10LUX: 10-20KΩ
Dark Resistance: 0.5MΩ
Power consumtion: 100mW
Good Value LDRsVery good value, but the resistance range was a bit less than more expensive ones I have previously bought (not a big problem though). Datasheet is here:
Cheap LDR with nice range.I didn't found some info about its minimum or maximum resistance. I measured few LDRs from Tayda.
It's about 150-180 Ohms with a super bright blue led in front of LDR, and about 600-900 kOhms in dark room. Well it would be better to use red led, but I had not some of them.
Also, it reacts pretty fast up to 30-40 kOhms, but maximum resistance is reached with 10-15 seconds.