... ratio (CTR: MIN. 50% at IF=5mA, VCE=5V)2. High input-output isolation voltage (VISO=5,000Vrms)3. Response ... light emitting diode and an NPN silicon,phototransistor2. The lead pitch is 2.54mm3. Replace for PC817 ,P521 series- Applications: 1. ... Computer terminals.2. System appliances, measuring instruments.3. Registers, copiers, automatic vending ...