The OS5RKA8131P is a surface-mount, TTL/CMOS, optical open-collector phototransistor, manufactured by Optosupply. It features a 4-pin DIP package, with a direct mount in order to facilitate installation in tight spaces. With a wide optical angle of 35 degrees, and a wide directivity up to 70mA, the OS5RKA8131P is designed for use in a range of applications including security labeling, consumer electronics, and medical devices. The device also features a low forward voltage of 1.5V max, making it suitable for low power applications.