TLP523,TLP523-2,TLP523-4 TOSHIBA Photocoupler IRED & Photo-Transistor TLP523, TLP523-2, TLP523-4 Programmable Controllers DC-Output Module Solid State Relay Unit: mm The TOSHIBA TLP523, -2 and -4 consist of an infrared emitting diode coupled with a silicon, Darlington connected, phototransistor which has an integral base-emitter resistor to optimize switching speed and elevated temperature characteristics. The TLP523-2 offers two isolated channels in an eight lead plastic DIP package, while t.