The GP1S194HCZ0F is a Transistor Output ROHS compliant DIP-4 Photointerrupters Slot Type made by Sharp. It is a four-pin, sealed optical coupler which contains an infrared LED and an integrated phototransistor, which is designed for use in precise, position sensing switch applications. In operation, the LED light beam is projected onto a reflective surface of a target such as a rotating disk. When the beam is interrupted, an electrical switch is created. This enables the detection of the exact position of the target. The GP1S194HCZ0F has a fast response time, meaning it can detect the pulse of compact targets, such as a small rotating disk, and is suitable for use in various applications, such as positioning devices, medical equipment, optical communication systems, robotics, and automation systems.