Inch product description 100 percent brand new and high quality using a wide voltage lm393 comparator with a mounting screw hole, easy to install using the sensitive type photosensitive resistance sensor the comparator output signal clean waveform is good, driving ability, than 15ma with adjustable potentiometer can adjust the brightness of the light detected working voltage: 3. 3V 5v output: do digital switch output (0 and, ao analog voltage output usage: this module is sensitive to the light, usually used for detecting the ambient brightness and light intensity. When there is no light or the light intensity can not reach the value, do output is high level. When light intensity over than the value, the module do output is low level. The module digital output do can be directly connected with the microcontroller, use microcontroller detect high or low level, so that can detect the environmental light intensity change. Can use this board digital output do port drive relay module directly(our store on sale these relay modules), can also use as a photoelectric switch. The analog output ao connects with ad module and it can get more precise light intensity value through the ad converter. Specifications: board color: blue board size: approx. 3. 2Cm x 1. 4Cm/1. 26 x 0. 55 Inch package include 1 x lm393 ldr sensor inch.