The primary types include phototransistor optocouplers, photodarlington optocouplers, photovoltaic optocouplers, and high-speed optocouplers. As semiconductor devices, optocouplers may be manufactured as one of several different form factors. These products are typically small, lightweight, and allow for fast and. The most common types of optocoupler are: Electronics is easy when you know what to focus on and what to ignore. Learn what "the basics" really is and how to learn it fast. They are suitable for general-purpose signal isolation. Understanding these types helps you choose the right one for your circuit.