The PC817B with SMD-4 Optocoupler by GOODWORK consists of an infrared light emitting diode and an integrated phototransistor in a compact surface-mountable package. The devices optically isolate the input from the output, providing electrical noise immunity and improved safety. These optocouplers are also ROHS compliant, meaning that all the materials used are free from hazardous substances such as lead and cadmium. Additionally, the package size allows for higher levels of integration, which makes it suitable for use in applications where space is limited. The optocoupler is also capable of operating at a wide range of temperatures, making it suitable for use in many different environments.