Transistor documentation for the 2SD1667, 136 KB in PDF format. Nothing beyond the part number appears in the name. The 2SD prefix belongs to the JIS scheme, marking an NPN bipolar device intended for low-frequency or power circuits. Expect the datasheet sections on absolute maximums, hFE classes and outline dimensions. Repair work uses this to identify pins before soldering and to vet alternatives from other makers. Remember the body may print only D1667, and package variants can change the pin layout.
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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