Optocoupler QX101X in 4-pin package with LSOP4 is composed of a light emitting diode and a phototransistor. QX101X Bottom of window    4-pin long creepage photoelectric coupler, transistor output summary QX101X is a photoelectric coupler composed of a GaAs LED and an NPN phototransistor. trait High input-output isolation voltage (Viso=5000 Vrms) Compact 4-pin SOP (thickness of colloid 2mm) 8mm long creepage distance app; application Power supply feedback circuit System, test instrument Registers, copiers, vending machines Household appliances, such as fans and water heaters.