I’ll research the manufacturer’s datasheet and sourcing information, then create a cited application guide covering wiring, layout, and replacement options.
I found a specification mismatch: the project description lists 35 V, while Sharp’s newer family datasheet lists 80 V. The project’s attached datasheet is still unavailable for verification, so I’ll clearly separate the manufacturer-family specifications from what can be confirmed for this library part.
The PC817 is a single-channel optocoupler containing an infrared LED optically coupled to a phototransistor, with a four-pin DIP package. A common practical use is transferring a low-speed on/off signal between electrically isolated circuits, using an LED current-limiting resistor on the input and a collector pull-up on the output.
Scope and verification: This library project is named PC817 but does not establish an exact manufacturer ordering code. Its description states 35 V and CTR 50–300%; those figures could not be verified against the project's attached datasheet, whose extraction remained pending after retries. The verified specifications below instead describe Sharp PC817XxNSZ1B, document OP18002EN...
Created the PC817 Application and Usage Guide, covering all seven requested sections, cited specifications, and 3.3 V/5 V resistor calculations.
The guide flags the unresolved 35 V versus 80 V specification mismatch and clearly distinguishes the verified replacement candidate from the second option still requiring verification; the schematic and footprint are unchanged.