Datasheet-like PDF of 116 KB covering the 2SC3638. Under JIS semiconductor naming, 2SC identifies NPN bipolar transistors. The name provides only the part number, so this is unlikely to be a device schematic despite its category. It should contain absolute maximum ratings, electrical characteristics and package dimensions. Technicians use it when identifying a failed transistor, confirming lead order and checking whether an available equivalent meets the circuit's voltage and current needs.
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.