Non-contact switching Single or double apertures for high resolution Choice of slot widths Choice of side-by-side or over/under dual channels Choice of electrical outputs OPB826 OPB822 Each OPB822 and OPB826 slotted switch consists of two infrared emitting diodes and two NPN silicon phototransistors mounted on opposite sides of a 0.090” (2.29 mm) wide slot (OPB822) or a 0.100” (2.54 mm) wide slot (OPB826). OPB822 uses an side-by-side mounting configuration, while.