PDF of 43.6 KB for the 3N252, listed under schematics though the name is a bare JEDEC part number. The 3N designation applies to registered semiconductor devices with four leads. Files for 3N246 to 3N252 share this exact size, which suggests a single datasheet covering that whole group. Use it to confirm pinout, voltage and current ratings and package type before measuring or swapping the component. Any PDF reader opens it; check the marking on the package to pick the correct entry in the tables.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @cyberlanelectonik. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.