100Pcs 5528 Light Dependent Resistor LDR 5MM Photoresistor 150VDC Retail Photoconductive Resistance photocell

These cadmium sulfide cells respond nearly instantly to changes in light, and have an incredible dynamic range that shows clear trends from bright direct sunlight down through nearly complete darkness (i.e., enclosed in a zipped neoprene pouch). Under typical indoor conditions, I see a resistance between 2k ohms and 30k ohms. Under the brightest illumination, resistance drops into the 40 ohm range. In darkness, the resistance quickly rises to 1M ohm, but continues to rise to the apparent limit of my multimeter (16M ohms). The cells respond to a wide spectrum of light, ranging from warm indoor lighting, though daylight and even a 365nm UV flashlight.I think the challenge of working with these cells will be in trying to achieve a digital sensing resolution over such a wide range, or at least choosing a portion of the range to sense with few bits. Also, if you're trying to compare readings between sensors, direct comparisons are challenging - some form of trimming or curve-fitting will definitely be required, and it might be best to plan for comparing each sensor onl to itself. In a comparison of three of these sensors under lighting as near to identical as I could make it, I saw readings of 3.35k, 3.46k, and 4.21k.For my purposes (hobby robotics / line & light following / day & night sensor), these will work perfectly.

I have been using these to make vactrols which is basically an LDR and and LED. When the LED gets voltage, it changes the resistance of the LDR which can create a low pass gate, useful for musical applications. I use these with standard 5mm red LEDs and the resistance range is good. I usually use some shrink tubing around the vactrol which keeps light out and protects it from damage.Good quality LDRs, obviously there are a lot more uses for these, mainly as a light sensor for Arduino and other projects and these will work well for those.

Not sure how to review this LDR. The ohms range seems to be within the 5528 spec. They however do not seem to be identical to others in the bag in terms of ohming the same in same lighting. If you need to make identical pairs you have to trim them with a pot.