The 2SK1120 N-channel field-effect transistor is documented in this 455 KB PDF, one of the larger sheets in the set and probably including full characteristic curves and package drawings. The 2SK designation follows the Japanese JIS scheme for N-channel FETs. No vendor or package is stated in the file name. Use the sheet to look up breakdown voltage, drain current and on-resistance, to identify pins for testing, and to match a substitute when the original device has failed.
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.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.