As is the case for TRIACs in general, phototriacs have traditionally been used as solid-state AC switches, but can also be used as simple DC latches in unique applications. Phototriacs are used where electrical isolation is required from driving source to load. This isolation requirement can be driven by electrical safety, as well as other requirements, including ground-loop and EMI mitigation. This application note discusses the types of phototriacs, their uses, and their critical design parameters.