Compact 33.5 KB PDF for the 2SC3664 transistor. The 2SC prefix, under the JIS scheme, signals an NPN bipolar device; nothing else is stated in the name. Given the small size, expect a short datasheet of one or two pages with key ratings and a pinout diagram rather than a schematic. It is handy when identifying a failed part on a board, checking collector-emitter voltage before choosing a substitute, and confirming which lead is base, collector or emitter for testing.
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.