PDF reference for transistor part 2SC4428, 107 KB, indexed under the schematic category. JIS numbering assigns the 2SC prefix to NPN bipolar transistors, so this is best treated as a datasheet giving ratings, characteristic curves and pinout. Technicians reach for it when a stage has failed and they need to know collector voltage limits, gain range or package before substituting. No manufacturer, revision or application is stated in the name; match the body marking and footprint on the PCB before trusting it.
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.