Seen this in many houses, people upgrade their lighting setup and install a dimmer. Which works. But usually it also makes the lights flicker unintentionally, which is super annoying IMO.
Now, my understanding of electrical engineering is pretty rudimentary so I’d appreciate more something that explains the concept in a way that Cavewoman Mothra can understand rather than something technically accurate.
Thanks
Dimmer switch limits the power. The light doesn’t like that.
Power coming into the house is AC which means 50-60 times a second the power goes from +110/240V to -110/240v.
LED lights run off DC power, so to change the power type a capacitor is somewhere that holds enough charge to keep the item working until the AC power is back to a usable positive value.
Dimmers limit the power going to the light, so the capacitor doesn’t charge enough to keep the light and circuitry on for the full negative swing of AC power.
This is ungodly rudimentary, and corrections are welcome. There is also many nuances I am missing.
It should be noted that there are LED bulbs that will take a dimmed signal and convert it into a dimmer light. If you buy dimmer capable LEDs (though that still doesn’t work with all dimmers), you can get dimmed light without the flicker, and without having to resort to smart home crap.
But you also need a dimmer that supports LEDs. Some dimmers have a minimum power requirement, which is much higher than almost every LED bulb
Dimmers will typically use a triac which cuts up the sinusoidal waveform. It doesnt actually lower the amplitude per se, but it limits the fraction of the time the waveform is on. Kinda like this. This means that a lot of the time the led isnt gettingas much or any power. The average power will be lower, and if the LED driving circuitry isnt designed to compensate for this, the LED will flicker.
Clarification on triacs: they get turned on a certain fraction of the way into the cycle. Triacs will stay on until the voltage across them is 0. Conveniently the zero-crossing of the AC wave (when the wall voltage crosses zero to start foing negative or from negative to positive) does just that.
I need an answer to this too (well maybe more of a solution, actually)… All the main areas of our home have dimmer switches. Some lights are LEDs, some are just your basic bulbs (like the ones in our ceiling fans). We like being able to dim the lights, especially in the bedrooms when the kids are getting ready to sleep (we also put down all electronics with screens), but ever so often these lights when dimmed will have a slight pulse like effect where it either goes a little darker or a little brighter (no rhyme or reason) and in my office you can slightly hear a little buzz sound when the light goes a little darker/brighter while the light is set to a certain level of dimness (for lack of better/technical terminologies).
Originally I thought it was just bad bulbs, so I did my office first as a test, but immediately after replacing the bulbs with brand new ones, it was not staying static to the dimness level I wanted, it would appear to randomly do the pulsating light effect.
Edit: Just read some of the comments…
So if anything LED lights will have the capability to dim, where as normal bulbs (I forget what they’re called - the bulb type) are not meant to. In order to have dimmable lights, I must buy both dimmable switches that are LED compatible and LED lights that are capable of dimming.
LED lights are either all on or all off, the only way to dim a LED, is to make it blink really fast and change the time it’s on vs the time it’s off. Cheap LED lights don’t blink fast enough, so you see them flicker.
That’s not the only way to dim an LED, just the cheapest. Variable current power regulators are the premium option.
A screw-in LED bulb combines LEDs and power regulating electronics. Some of them handle the variable input voltage a household dimmer provides gracefully, but that’s more expensive.
