On Friday, June 30, 2017 at 2:00:04 PM UTC-4, Ian Field wrote:

Some LED bulbs are switch mode, usually flyback AFAICT. They are pretty much
the same as CFLs on a triac dimmer.

http://creebulb.com/bulbfinder

We use Cree lamps where we need dimming, and in general if replacements. We still have some few legacy LED lamps in place (stuff that came-with other stuff), but we do not intend to dim those.

NOTE: some cheap LED lamps are very noisy in the RF range. VERY noisy, approaching that of an unshielded ignition transformer (oil burner).

Peter Wieck
Melrose Park, PA