"John Rumm" wrote in message
...
:Jerry: wrote:

AIUI the LEDs, within the common housing, do the 'steering',
depending on which tail is ve+. Also there are tri-colour LEDs
which emit their third colour when supplied with an AC supply
rather than DC.

No, that is still a bi-colour - the AC just flashes each "side" in
quick alternation allowing the eye to integrate the colours. A true
tri-colour LED has three leads allowing both sides to be lit in
parallel.


With respect, that sounds like dancing on the head of a pin...