LONG DISTANCE PHOTOSWITCH REFLECTS TO DISTANCES OVER ONE INCH

Providing design engineers with a reflective device capable of operating in dusty environments, TT electronics OPTEK Technology has developed a long distance infrared switch that has a reflective distance of more than one inch, depending on circuitry. Designated the OPB732 Series, the reflective switch configuration includes an infrared LED and phototransistor, and uses an opaque housing to reduce the sensor’s ambient light sensitivity. "While an object is in the path of the device, light from the LED will be reflected back to the housing, irradiating the surface of the phototransistor," explained Alan Bennett, vice president of sales and marketing for OPTEK Technology. "Both the emitter and sensor are protected by a clear window, which allows the device to operate in dusty environments, such as those in industrial and automotive applications." The OPB732 reflective switch is also ideal for non-contact reflective object sensing circuits in equipment security, machine safety, assembly line and machine automation, as well as door and end-of-travel sensing applications. When infrared light strikes the phototransistor, it becomes forward biased and is considered to be in the "on" state, providing an IC(ON) current proportional to the light striking the phototransistor, Bennett continued. When the infrared light from the LED is not reflected to the phototransistor, the device turns "off," minimizing the IC(ON) current. The OPB732 Series light emitting diode features an 850nm wavelength and a power dissipation of 100mW. Maximum forward current is 50mA and maximum forward voltage is 1.8V (If=20mA). Reverse DC voltage is 3V, with reverse current of 100mA (Vr=2.0V). Electrical performance of the output phototransistor is characterized at collector-emitter voltages of 30V, collector DC current of 50mA, and power dissipation of 100mW. Operating temperature range for the long distance reflective switch is -408C to +858C. The OPB732 Series assembly is offered with either PC board through hole pins or 24", 26 AWG wires. The phototransistor can be configured as a common collector or common emitter device. OPTEK Technology is a leading manufacturer of standard and application-specific sensors using infrared, visible, magnetic and fiber optic technologies focused on applications in office machines, industrial equipment, encoders, automotive electronics, military and high-reliability applications, and medical diagnostic equipment. Headquartered in Carrollton, TX, the company is ISO/TS16949:2002 and BS EN ISO 9001:2000 certified, as well as ITAR registered. OPTEK Technology was acquired by TT electronics in December 2003. TT electronics plc is a global electronics company manufacturing a broad range of advanced electronic components, assemblies and sensor modules for the automotive, industrial,