Part 2SC5043, a JIS-numbered NPN bipolar transistor, is the subject of this 106 KB PDF, which the index files as a schematic but which is presumably a datasheet. The name offers no maker, package or revision data. Technicians open such a document in any PDF viewer to find pin order, maximum ratings and gain class, then use those figures to test the part with a meter or to select an equivalent with matching voltage, current and frequency capability.
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.
Any PDF readerSumatraPDFFirefox / ChromeFlexBV (links PDF to boardview)