GALLIUM-ARSENIDE LIGHT EMITTING DIODE OPTICALLY COUPLED TO A PLANAR SILICON NPN DARLINGTON PHOTOTRANSISTOR BOTH OF WHICH ARE IN A PLASTIC CASE; REVERSE VOLTAGE 3.0 VOLTS FOR L E D; COLLECTOR-EMITTER BREAKDOWN VOLTAGE 30.0 FOR PHOTOTRANSISTOR; POWER DISSIPATION 90.0MW; 0.450 IN. MAX LG; 0.280 IN. MAX W; 0.200 IN. MAX H