I've been trying to research dimmers. Long story short, I have an antique brass floor lamp that I'm re-wiring. I don't have a picture of mine, but it's the style with one socket on top and three side sockets on different switches, like this:
I have all new wiring run through things. The plan is to stuff some dimmable LED bulbs in it with separate rotary dimmers for the single upper and triple lower sockets. In the process of scouring Amazon for dimmers, I'm confused.
Here are my assumptions. Can you tell me which ones are correct/incorrect?
- dimmable LED bulbs are equipped with their own PWM circuitry to convert the variable voltage from a traditional potentiometer into PWM to control the diode. Therefore any normal, analog potentiometer will successfully control a dimmable LED.
- some dimmers are listed for "incandescent only." This is to indicate that they will not control a traditional LED, but are fine for a dimmable LED since the bulb itself does the magic.
- a dimmer that is designated for LEDs is actually a PWM control?
I feel as if I had a more complete understanding of the different types of dimmers I could make easier choices about stuff like this.
Different country and voltage but I have recently done my house with LED's so take the following with a teaspoon of salt 
With dimmable LED's the work is all done in the actual driver box which is sometimes external, or sometimes in the base of the bulb. I don't know what circuitry is actually in there but mine all expected some variation on PWM (pulse width modulation).
Incandescent dimmers, in my experience, are also PWM - I have never encountered a potentiometer / rheostat scenario at other than low voltages and brightness. Imagine the power dissipation inside the little light box in the wall controlling 100 watts or so 
Where there is a difference is which end of the pulse gets shortened. Some dimmers are tagged "trailing edge" and some "leading edge". When I did my lounge from incandescent to LED I had the wrong kind and had to buy new ones but the dimmers in the bedrooms were all OK.
The LED packaging / destructions should tell you whether you need leading or trailing ...
cheers
R
I hope this thread is enlightening (pun intended.) I replaced my living room lights with "dimmable" LED bulbs some time back, still being run with the traditional slider style incandescent dimmers. They dimmed, but also flickered pretty consistently, enough to annoy everyone. I replaced all the dimmers with "LED capable" slide dimmers. Better, but still flickers enough that it's unacceptable. Switched out LED bulbs for a cheaper, Home Depot brand that had a display set up showing that they dimmed. This setup is much better, only flickers once in a while. Acceptable, but not ideal still.
Maybe someone has a magic combination?
In reply to ultraclyde (Forum Supporter) :
This was partly my hope for clarification. My house had old-school rotary "rheostats" likely installed in the 60s. I retrofitted the entire house with dimmable LED bulbs and they worked just fine. No flicker, no noise. I have since upgraded to new switch style dimmers that said they were approved for LED (the style with a normal looking switch with a tiny slider stuck beside them) and they still worked just fine.
I also installed a new rotary LED-approved dimmer on my patio string lights which have dimmable LED edison-look bulbs. They dim ok, but not linearly. When you turn the switch on, they glow at about a 4 and stay at a 4 for most of the rotation. Then they drop to 1 and dim up to 10 for the last, maybe 10 degrees of rotation.. I blamed it on the fact that the bulbs were chinese cheapy bulbs from Amazon. I'm fine with it since I still get the full range of lighting possibility, just with a little operator finesse at the switch. I verified that the dimmer was good by replacing one bulb with an incandescent, and the dimmer does what it needs for that bulb.
RichardNZ said:
Different country and voltage but I have recently done my house with LED's so take the following with a teaspoon of salt
With dimmable LED's the work is all done in the actual driver box which is sometimes external, or sometimes in the base of the bulb. I don't know what circuitry is actually in there but mine all expected some variation on PWM (pulse width modulation).
Incandescent dimmers, in my experience, are also PWM - I have never encountered a potentiometer / rheostat scenario at other than low voltages and brightness. Imagine the power dissipation inside the little light box in the wall controlling 100 watts or so
Where there is a difference is which end of the pulse gets shortened. Some dimmers are tagged "trailing edge" and some "leading edge". When I did my lounge from incandescent to LED I had the wrong kind and had to buy new ones but the dimmers in the bedrooms were all OK.
The LED packaging / destructions should tell you whether you need leading or trailing ...
cheers
R
This is great info, thanks. One of the problems is I'm dealing with big box stores or Amazon. For the most part, the big box stores are staffed with at least one knowledgeable person, but they're 65 and haven't really had much experience with the newfangled stuff, or Amazon which is one big Sherlock Holmes mystery. You mostly have to read the reviews and see if someone posted that this product functioned ok with their LEDs regardless of what the seller's description says.
None of them on Amazon have offered any insight on trailing edge/leading edge. Most of them say "works with LEDs" and then in the reviews someone says "doesn't work with LEDs" Then you have to use Sherlock Holmes level skills to try and figure out from context if they were using dimmable LEDs or if they just assumed it would work on their non-dimmable $5 LED tape
Most of the problem is standardizing. Most of the Chinese drivers are not the same or work with other manufactures product. It's been getting better over the last ten years but still not great. Found it's best if you can stay with one manufacturer for the lamp and driver if possible. Even with commercial systems it can be hit and miss if they work or not.
I did a little more reading today and I can add to the discussion is that the biggest issue really is compatibility between the drivers (the interface between 230, sorry 110, line voltage) and the actual needs of the LED. It seems there is no actual standard out in the real world yet ...
Updated advice then is to try and get a Dimmer made by the same manufacturer as the LED or if that's not possible work with a bricks and mortar store on a try and buy scenario to find a pairing that works.
R
PS the old guys in the big box stores may be old but they do have experience and are generally willing to learn new things because that's what most of that generation did as a matter of course. FWIW I'm 69
'round these parts, manufacturers don't really cross over. Lights are plentiful; Phillips, GE, Feit, CE, Sylvania, but dimmers are usually Chinese, Westinghouse, or Leviton.
And, of the light manufacturers, they are mostly assemblers these days. It used to be that if you bought a Phillips incandescent bulb, they blew the glass and put their filaments in it. Now they outsource stuff and they just assemble pieces. Hard to know. You might get one box of GE bulbs with Cree diodes, and another box a week later with Osram.
Update. I ordered THESE which clearly say "incandescent only."
They work fine with GE and Phillips dimmable LED bulbs.
Well done, they will make your light truly great ...
Taking a slight diversion, my electrician friend visited yesterday and he is about to fit all new LED down lights in their, new to him, house. The ones they have selected are wi-fi enabled and are controllable for brightness and colour temperature. They are controlled by either a remote control or a phone app. As a smartphone Luddite he's getting the remote control but I'm sure his wife will use her phone 
.
That means you can have fun driving by his place, stealing his wifi, and messing with the lights.
I used to do that with SWMBO's stereo. We would be watching a movie and I would control her sound bar with my phone. It took her a good long while to figure it out. I would mute it and turn it up really loud. She would go unmute it and get scared by the volume. She threatened to take it back to the store before I told her it was me.
Now I just need to find a shade for this lamp.
