Datasheet for the IRF510 N-channel MOSFET, a 97.7 KB PDF. The document should cover ratings, transfer and output characteristics, capacitances and the TO-220 pinout. This small power transistor turns up in hobby RF amplifiers, drivers and low-power switching circuits, so the sheet supports pin identification, bias planning and selection of a suitable substitute. Any PDF viewer opens it. Verify the manufacturer and package of the part on the board, since gate threshold and capacitance figures influence behaviour in RF and linear uses.
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.