PC817X Series contains an IRED optically coupled to a phototransistor. It is packaged in a 4pin DIP, available in wide-lead spacing option and SMT gullwing lead-form option. Input-output isolation voltage(rms) is 5.0kV. Collector-emitter voltage is 80V(*) and CTR is 50% to 600% at input current of 5mA.
1. I/O isolation for MCUs (Micro Controller Units)
2. Noise suppression in switching circuits
3. Signal transmission between circuits of different potentials and impedances.
See full feature at datasheet from below: