THD In Light Bulbs

If you are not using a dimmer, then I would not get too worried. It's just another small switching power supply on your AC line, and odds are you already have quite a few (all those USB chargers, and they can be worse).

If you have a dimmer, then yes, things could be noisier as the power supply in the bulb will have capacitors on the front end which will result in higher peak currents when the dimmer turns on (120 times a second, 100 in some parts of the world).

There are some bulbs/lights that do not have switch mode power supplies in them, but simple linear regulators. They are common in low cost flush mount ceiling lights, but not very common in bulbs. I would avoid most as they can have lots of invisible flicker.

Can someone elaborate on smart light bulbs?  I recently added 8, color changing, dimmable, smart led bulbs from sengled...

https://e2e.ti.com/blogs_/b/powerhouse/archive/2013/05/28/how-to-reduce-total-harmonic-distortion-to-below-10

twoleftears,

That is a link to a highly technical article, that is itself really only applicable to one IC / control architecture. Most EEs would not understand the subtleties of it, let alone most people here. It is really not applicable to the ops question.

Basically a switching power supply, akin to a USB charger, and about the same power level as well.

I don't see anything about EnergyStar for these bulbs. If they were EnergyStar, they would have to meet some minimum power factor requirements that would normally mean less harmonics on the AC line. Since they don't appear to be, they could be poor (akin to those USB chargers).

b_limo1,065 posts01-04-2020 12:01pmCan someone elaborate on smart light bulbs?  I recently added 8, color changing, dimmable, smart led bulbs from sengled...