I'm trying to date a circuit from an organ. It contains transistors in a TO-92 (plastic) package.
Approximately when did these transistors first appear?
I'm trying to date a circuit from an organ. It contains transistors in a TO-92 (plastic) package.
Approximately when did these transistors first appear?
Edit
Thanks for the picture, by any chance are their any identifying text left on the packages or the boards? Just a shot in the dark, but I would say that board was from the aprox: 1972 to 1985. But it depends on so many other factors. And it also my not be original to the organ it'self.
I'm trying to date a circuit from an organ.
It would be the easiest to just look up the organ...
Date of introduction of TO-92 transistors. Approximately when did these transistors first appear?
The TO-92 spec was introduced in the 1960's (I believe but can't find a source,) and became a standard by JEDEC Solid State Technology Association years later.
FYI, none of this information will help you date the organ's board!
It depends on the actual model of the transistor and a few other factors. Semiconductor material (date first used):
Look for date codes on (unlikely) the transistors; (likely) any TO3 transistors in the power supply; definitely ICs if there are any; and (sometimes) large electrolytic capacitors, again in the PSU. Also that screened can (inductor?).
Earlier than 1970 I think the TO18 can would be more common (there's 1 in your picture) and much later, ICs would start appearing (along with 5% resistors rather than 10%) so I doubt it's as late as 1980.