A 101 KB PDF carrying only the part number 2SK223. Following JIS conventions, 2SK marks an N-channel FET, so the document is likely a datasheet although categorized as a…

Listed as a schematic, this 422 KB PDF carries the part number 2SK2232 and is most likely the datasheet for that N-channel FET.

The file name gives nothing beyond 2SK2233, a JIS/EIAJ designation whose 2SK prefix marks an N-channel field-effect transistor.

Part number 2SK2231 is the only information carried by this 420 KB PDF, which the index places among schematics but which most likely documents a single transistor.