An 86.0 KB PDF carrying the part number 2SC3998, catalogued as a schematic but by name a single-device datasheet. Under JIS rules the 2SC prefix marks an NPN bipolar transistor. Manufacturer, package and ratings are not stated in the name, so take them from the document itself. Typical uses are confirming the pinout, reading absolute maximum ratings and checking whether a replacement is suitable. Open it in any PDF reader, and compare the number printed on the component with this one before trusting the information.
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.