The MID400 is a AC line to logic Power Line Monitor Optocoupler. Meaning, the output of the IC goes low whenever it detects an AC voltage and goes high when no AC voltage is present.
VOH1016A – 1MBd High Speed Optocoupler with Schmitt-Trigger Functionality
For easy integration with Digital system applications Vishay intertechnology has launched a new series of high speed Optocouplers called VOH1016A. These Optocouplers can operate upto 1MBd and also features an open collector transistor output with Schmitt-Trigger functionality.
6N139 is an optocoupler IC designed for isolating primary circuit and secondary circuit electrically but the pair of LED and photodiode - Darlington setup forms the triggering mechanism between the two sides.
4N25 Features and Specifications
IR LED Forward Voltage for turning ON: 1.25V-1.5V (Typically 1.3V, 1.5V being absolute maximum forward voltage)
IR LED Forward Current during ON: 10mA - 60