On Sun, 22 Oct 2017 15:16:25 +0100, "Dave Plowman (News)"
wrote:

In article ,
Harry Bloomfield wrote:
on 22/10/2017, Jeff Layman supposed :
The trouble is that they are sold as low-power replacements for
halogen bulbs, to be used in the same fitting. Halogens have a
pretty-much 360 degree beam, and it doesn't matter too much how the
reflector is designed. But put an LED in the same reflector, and you
usually have a problem.

You can specify 'corn-cob' LED, which has light output around the
entire lamp, except the base.

These seem to be less efficient than single LED units.

I think that's because the corn cob lamps use SMB chips, which are not
as efficient as the COB chips used in single LED units.