How to wire a 12v LED to 120V Dimmer

If your 12V LEDs have built-in drivers (they're more than just plain LEDs), you might not be able to reliably dim them at all.

If they're just LEDs, you need a dimmable LED driver with appropriate voltage and current ratings, one that can be dimmed by standard triac dimmers. For example, something like this might work. If it's LED tape, that still might work, though tapes often also have dropping resistors and might not be quite as well behaved when dimming.

In any case, don't expect perfect fades to black or from black, but rather a sudden turn-off at some point and an equally sudden turn-on going the other way. Better control would almost certainly be had by using a DMX512 controlled LED dimmer, e.g. this sort of thing.

(I have no experience with either of these products, nor any reason to recommend for or against these particular units; they're just examples of the sorts of things available that you might use.)
 
Yep dmx controller using a 12v supply (car battery?) and a DMX feed either by cable if fixed in place or wireless if it has to be movable (I do this all the time)
Don't waste your time trying to convert 120V ac to 12v dc to run your LED.
Regards

Geoff
 
Okay. Thank you! I don't have much time since this was pretty much thrown to me right before tech, so I think I'll just rip the LED out and just put a bulb in. Less to figure out in the middle of tech.
 
I've used the three channel LED DMX dimmer board linked to with both LED tape and individual 10mm clear LEDs (with suitable current limiting resistors) and they work reasonably well. They're a bit "steppy" as they only have 255 steps, but work well enough.

On set pieces where a trailing cable wouldn't be acceptable I use RC4 wireless dimmers. These are excellent and dim smoothly. I've also used the RC4 receiver purely as a wireless DMX link when I needed to.
 
If you have the budget to order a DMX-controllable 12V LED driver, that’s probably easier than reworking the piece to be 120V. Do you already have a piece built with 12V LEDs in it? If so, the wiring and general construction is probably not suitable for 120V operation, from a safety perspective.

LEDs that are rated for 12V are inherently current-limited. Otherwise, they don’t have a voltage per se, they have only a maximum current rating. (Don’t confuse an LED’s Forward Voltage, a.ka. Vf, as an operating voltage. That number is usually somewhere in the 1.5V - 3.5V range.)

Warnings about dimming quality are very real. If it’s LEDs tape, it can dim super smoothly. If it’s an MR-16 emulator, then it probably will *not* dim very well, especially at the bottom end.

Tell us more about the LED and the set piece. More detail, and we can be more helpful.

Jim
RC4 Wireless
 

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