This part is a kind of semiconductor called GL5528.
Function of this product has GL5516 - GL5549 Photoresistor.
Manufacturers : ETC
Image and pinout :
Some of the text within the PDF file :
Free Datasheet http://www.datasheet4u.com/ Free Datasheet http://www.datasheet4u.com/ [ ... ]
GL5528 PDF Datasheet Download
