It covers the IL300's coupling specifications, and circuit topologies for photovoltaic and photoconductive amplifier design. This application note presents isolation amplifier circuit designs useful in industrial test and measurement systems, instrumentation, and communication systems. The LOC product is intended to. Vishay's IL300 linear optocoupler consists of an AlGaAs IRLED irradiating an isolated feedback and an output PIN photodiode in a bifurcated arrangement. High accuracy, linearity, and time-temperature stability are achieved by coupling light from an LED back to the input (negative feedback) as well as for- ward to the output.