The PT17-21C/L41/TR8 is an IR Phototransistor manufactured by Everlight. It is a 5.6mm × 4.0mm visible red LED-infrared phototransistor combination, which includes an 8-inch long lead forming tray. The phototransistor consists of an infrared light-sensitive NPN silicon phototransistor and a visible red LED, and is designed to optimize effective radiant sensitivity and improve ambient light immunity. When used in combination, the visible light emitted from the LED is used to control the amount of infrared light that is detected by the phototransistor. The nominal collector-emitter dark current is 0.5µA and the collector-emitter dark current is 0.01mA. The PT17-21C is also RoHS and REACH compliant.