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LED Christmas lights - love 'em or hate 'em?

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tom66:

--- Quote from: 25 CPS on November 27, 2020, 10:48:22 pm ---I'm curious, does anybody know what the utility companies position on LED lighting is?  I remember reading about a 1970s TV regulated power supply circuit that introduced a nonlinear current waveform that caused some issues in places where it was in common use at the same time of day so I was wondering if LED lighting, Christmas or otherwise, being a nonlinear load has been a problem or at least something that's noticeable from the electricity utility end?

--- End quote ---

My guess is it has a negligible effect compared to things like motors in washing machines, which are often triac-chopped, or small switch mode power supplies (sub ~50W) which don't require PFC.

james_s:
IIRC most of the decent quality LED bulbs have a reasonable power factor, I'll measure a few different bulbs next time I've got the stuff out. Christmas lights will be cheap and nasty of course but those are negligible, being used for only a few weeks out of the year and mostly in modest quantities.

tom66:
Our LED bulbs run off AC transformers and the controller decides which pair to light by chopping the positive or negative.  I imagine that having a modest inductance in the circuit goes some way to reduce the effects on the power grid.

madires:
So far I've seen LED fairy lights with some sort of controller powered only by a small SMPSU wall wart. Half the LEDs in the string are wired in parallel, and the other half anti-parallel. The controller generates a PWM and also switches the polarity to select which half of LEDs to light. Usually they have 8 modes.

Cyberdragon:
We have all the way up to RGBW LED strings here, saw a tree lit with them at Micheals.

I prefer incandescant to LED, the warm white ones aren't that bad though (the unrectified ones are a bit nasty though).

I like the color of (multicolor) phosphor LEDs better than bare dies, but I haven't seen them outside of battery sets, where they are used so they all drop the same brightness as the batteries drain. I would love to get a hold of a set of vintage phosphor light string, while dim the color is very unique.

Another thing about LEDs is the current draw is low enough that they can be easily driven from audio output vacuum tubes. One of these days I want to try and build a lighting controller using tubes, it would probably probably only have a few functions and I'm limiting it to a three color string. Also decatrons are pretty much off the table since they need 350+V which is well above the about 160V of rectified NA mains. You might be able to get away with using them on european recified mains but they might be unstable.

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