Datasheet for the 2N2222, the long-established general-purpose NPN switching transistor, as a 79.5 KB PDF. Typical contents include maximum voltage and current ratings, gain at various currents, switching times and package drawings for metal-can and plastic versions. Technicians use it to identify pinout, which differs between TO-18 and TO-92 forms such as the PN2222, test the device with a meter and evaluate substitutes. Open it in any PDF reader, and check the package and exact prefix printed on the part before matching pins.
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.