A 185 KB PDF for the 2SC5331 transistor, indexed as a schematic although the part-number title points to a datasheet. Japanese JIS numbering uses 2SC for NPN bipolar transistors. Such sheets normally list voltage and current limits, gain figures, the package drawing and lead assignment. No manufacturer or target equipment is named, so compare the body marking and package before trusting it. Use it when testing a suspect transistor with a meter, or when picking a replacement with equal or better ratings.
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.
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The standard format for schematics, block diagrams, power-sequence charts and service manuals.