On 14/10/2020 20:05:06, T i m wrote:
On Wed, 14 Oct 2020 16:35:07 +0200, Thomas Prufer
wrote:

On Wed, 14 Oct 2020 14:16:07 +0100, T i m wrote:


But it still wasn't clear if there was a code that described that base
(with two connectors and one filament) exactly?

B15d, aka BAY15d, as in

I thought that was the case but it doesn't seem to specify the number
of connections?

https://www.amazon.com/dp/B004VSG858/

The picture seems to suggest there is only one central connector?

and there the spec drawing of the base.

Thanks for that but again, I'm not sure if the diagram is indicating
there are one or two connections on the bottom, as the view is from a
direction that would mask the second connector behind the first?

This is why I was unsure if there was a formal designation for this
base and wiring (two connections, one filament and not using the metal
of the cap as a (ground) connector).

eg, The layout of this is more like a mains powered bayonet lamp

https://ibb.co/bPstyRf

Which is a BA15d
https://en.wikipedia.org/wiki/Bayonet_mount

https://ibb.co/gw6wHjM

I assume the relevant fitting.

I might be able to get a single element lamp to make contact with
either / both of the two contacts or if I use a twin element lamp, run
them individually or in parallel.

If you google "BA15d 12V LED" the first hit:
https://bedazzledledlighting.co.uk/p...d-bulbs/ba15d/

You will have a selection of spots/lights. One I looked at worked from
10v-30v DC.

But I suspect I'm in your killfile?