PDF datasheet of 52.2 KB for the 2N2369 NPN switching transistor, placed in the schematic section. This part is valued for very short turn-on and turn-off times and appears in pulse generators, drivers and older high-speed logic. The document lists lead layout, maximum ratings, gain and switching characteristics, which matter when a slower general-purpose transistor is being considered as a substitute. Check the outline drawing against the fitted component, as metal-can and plastic versions exist with possibly different pin orders.
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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