Covering the plain 2SC5261 without suffix, this 183 KB PDF is indexed as a schematic but concerns a single NPN bipolar transistor, as the JIS 2SC prefix indicates. An FT variant is catalogued separately, so make sure the marking on your component matches the unsuffixed part. The file is useful for reading pin assignments, package outline and absolute maximum ratings, which guide diode-mode testing and help decide whether a proposed equivalent can safely take its place in the circuit.
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.