Isocom h21ah22a series photodetectors 3mm aperture 1 channel isocom h21a1 a high gain single channel photodetector with a 3mm leddetector gap uses an ir led and npn silicon phototransistor specially designed package optimises mechanical resolution coupling efficiency and ambient light rejection suitable for applications such as copiers printers fax machines av equipment etc isocom h21a1 photointerrupter 12v 50ma through hole transmissive