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I've got halogen spot bulbs, with GU10 connector, throughout my living room. All connected to one halogen dimmer. I'd like to replace them with LED spots, using the same fixtures as the halogen spots.

This made me wonder. There are LED spots that are specifically labelled dimmable. For halogen you need a special halogen dimmer. What kind of dimmer do LED spots require? The same as halogen spots or does a normal dimmer work as well?

I've tried one LED spot with my current halogen dimmer, and it works. It doesn't, however, dim the light as low as with halogen spots. This could, of course, be because it's simply not possible to dim LED spots that low. On the other hand, could the fact that I'm using a halogen dimmer instead of a normal one or the mix of halogen and LED spots in the same circuit be of any influence?

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  • \$\begingroup\$ I would have loved to add the halogen tag, but I'm not allowed to because of my limited credits. \$\endgroup\$
    – Forage
    Apr 25, 2014 at 12:00
  • \$\begingroup\$ A halogen tag is not needed. The thing is, for the most part, led dimmers use pwm, while halogen use scr or resistive dimming methods. I may be wrong. \$\endgroup\$
    – Passerby
    Apr 25, 2014 at 14:07
  • \$\begingroup\$ You can get a dimmable LED. They have to state they are dimmable. I have a dimmable 18W (like 100W incandescent) in a floor lamp with a halogen dimmer. The Amazon category is Tools & Home Improvement : Light Bulbs : LED Bulbs : Dimmable \$\endgroup\$
    – Chloe
    Feb 3, 2016 at 18:09

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50/60 Hz dimmers for nonlinear loads such as LEDs have stability issues at large phase angles where the voltage is dropping, so they use PFC to linearize the load. Recent chips can handle power LEDs down to < 1% power, flicker-free.

If you want a cheap and dirty solution, leave one filament bulb as a linear load in parallel with the rest being LEDs and that will work.

Mind you, the health risks from 120Hz flashing LEDs are being investigated for eye-brain strain, so PWM >1kHz is preferred.

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  • \$\begingroup\$ My electrical knowledge is quite rusty and I was planning on digging into it again because your reply was too technical for me to understand, but I just can't get round to it. In my current situation with just one LED along with halogen spots the LED spot remains bright enough to read a book if turned all the way down. Is this a LED spot or dimmer issue? Also, dimmers I found so far (like Busch-Jaeger) have no mention of PWM nor frequency in their specs. \$\endgroup\$
    – Forage
    May 24, 2014 at 14:59
  • \$\begingroup\$ I have stumbled across this while looking for some information myself, however I think I read that because the consumption of the LED bulbs is so much lower than the standard halogen type, the halogen dimmers are over-sized and are not as sensitive which may be why they don't dim as well. \$\endgroup\$
    – TomC
    Apr 27, 2016 at 16:27
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A cheap method of what you want can be done with just a few components. All you need is a 12V Led, Transformer from 230V to 12V, Led dimmer module and a potentiometer (A Halogen Dimmer would fit though). Sometimes there are also dimable ledspots which uses 230V but these are rare. As user40708 already said, your can dim a ledspot with PWM which means Puls Width Modulation. You should be able to dim your led lights from 100% to 0%. So dimming a led light could be as low as you want (You'll see just a small dot light on 0% so small that you can't even see the spot it self).

Schematic

You could also use this.

enter image description here

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  • \$\begingroup\$ Note that you might need a separate Led dimmer for every ledspot and/or more then one transformer depending on how much these things can offer to a led. Just connect the dimmers parallel and and transformers in serie (the 230V side). \$\endgroup\$
    – Handoko
    May 22, 2014 at 22:46
  • \$\begingroup\$ Thank you for your elaborate answer, but I think you're missing the point of the question. It basically comes down to "Is using a halogen dimmer the cause of my LED spot not dimming all the way? If yes, can it be fixed with that dimmer or should I get a LED dimmer?". Because I'm on GU10 connectors I'm forced to resort to 240V dimable LED spots as well. These are quite easy to find actually. \$\endgroup\$
    – Forage
    May 24, 2014 at 14:41
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    \$\begingroup\$ You'll just need a dimmable led driver. You can dim your led driver using the halogen dimmer. \$\endgroup\$
    – Handoko
    May 24, 2014 at 14:53

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