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[–] BlockMe 0 points 8 points (+8|-0) ago 

An LED is a diode. All diodes have a threshold voltage below which they will not fire. It's a little more complicated than that. As the current flows through a diode, its characteristics change, and a slight fluctuation in voltage could cause an increase in current, which would then burn out the diode.

I don't recommend anyone install these LED dimmers as they (a) emit high frequency noise which your dog can hear and (b) they confuse smart meters and can give you a fatter electricity bill for no fault of yours. Ditto for CFL dimmers.

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[–] Gravspeed 0 points 0 points (+0|-0) ago 

Completely correct. I have very sensitive hearing and i can hear them. I'm sure our dogs hate them.

A lot of the smart lights are pwm controlled and don't whistle.

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[–] smashbery 0 points 0 points (+0|-0) ago 

is this all LED dimmers or just a few brands ? are you recommending to go with just a LED on off switch ...

i know when i put in leds i had to change the switches , with the old non led stwiches when i had them in the "off" position they would "glow" ever so softly and you could only see it in the dead of night.

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[–] Talc 0 points 1 points (+1|-0) ago 

it's most brands, there are suppressed ones on the market but most are little RF noisemakers and the only way to tell which are which is to set one up and see how much noise it puts out. A lot of the "buck" style voltage regulators built into led fittings and bulb replacements are just as bad. If you want a low noise dimmable fitting, in my experience LUMO are the best, I've fitted them in multiple boats and RVs, never had a problem with one, but they are expensive.

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[–] Snu-snu 0 points 0 points (+0|-0) ago 

Interesting swapping the switch fixed the problem. Must have been some stray voltage bridging the switch. An incandescent won't heat enough on 10v but an led only needs 1.7v with 20ma so turn on is much less

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[–] Snu-snu 0 points 0 points (+0|-0) ago 

If you get a higher quality dimmer it won't have the hum. You're right about the meters, the smart meter is based on a perfect sine wave while PWM is far from that lol. Works much better on a motor like a VFD. Power quality is turning into a big thing in the electrical industry as more of these electronic switching frequencies are being piled on top of each other on each branch making it extremely noisy. Won't be long before whole home filtering is commonplace

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[–] MJStone 1 points 4 points (+5|-1) ago 

Google how an LED works. It won't turn on unless you hit a certain voltage. There's probably a tiny window of brightness you can achieve between it's turn on voltage and it's max voltage before it burns out.

In order to get a greater range of brightness you can use pwm to very quickly toggle the LED on and off. By adjusting the ratio between on time and off time, the brightness your eye can perceive can be adjusted.

The pwm toggles so fast that you can't see the LED turning on and off.

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[–] kinghellman 0 points 1 points (+1|-0) ago 

Yeah, most of those dimmers destroy the ability to DX AM radio stations at night.