In article ,
Roger Hayter wrote:
Any guesses as to the purpose of this diode?
A number of possible reasons. They may have wanted 4.3V for a reason.

Doubt it, as it merely feeds what are effectively pots.

Most likely, though, in case the supply got connected to 12V either due
to a wiring fault or because someone assumed all live connections should
be 12V.

That does seem the likely explanation. Although there is also a zener to
take care of possible over voltage.

--
*My wife and I had words. But I didn't get to use mine.

Dave Plowman London SW
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