# Why are MR16 LED bulbs AC? Will they run ok on DC?



## fpbear (Feb 7, 2014)

I thought DC is the most natural way of powering LED. I'm looking for a 12VDC MR16 pendant bulb, but I'm noticing all the MR16 LED bulbs I'm coming across are listed for 12VAC. Will these run ok on DC as well?

Here's what I'm trying to do. I have a nice magnetic transformer power supply powering 12VDC LED strips, and that is dimmed with a Lutron Radio RA2 adaptive phase dimmer. I want to add a nice pendant light on the same circuit so it uses the same dimmer (need to have a decent selection of nice looking hanging pendants for this display). Originally I was thinking to have mixed loads on the dimmer (12VDC LED strip + 120VAC LED standard Edison bulb) but it might be too risky to have a magnetic load + LED load without knowing what kind of circuitry is inside the particular LED bulb (not good to mix magnetic + electronic loads on the same dimmer). So I think a simpler/safer solution is to find a nice 12VDC pendant and put it on the same magnetic output.


----------



## Reedman (Dec 16, 2014)

1. To get specific/pedantic, you are talking about MR16/GU5.3 lamps. I have not seen one that doesn't run on 12 volts DC as well, or better, than on AC.
The GU5.3 lamps have the bipin/2 straight-pin base. There are MR16/GU10 lamps with bayonet bases, with machined pins, which are intended for direct
connection to the utility AC lines (120VAC versions for North America, 230 VAC versions for the rest of the world.
2. The reason all the lamps are spec'd for AC operation is because all the lighting infrastructure ahead of the lamps is AC -- dimmers are AC, transformers are AC (both magnetic
and electronic). There are a few DC dimmers (reference Reign from ElementalLED), but they are few and far between, and require a power supply to provide the DC
(power supplies are generally more expensive than transformers). The good news is that because the lamps are AC, they don't care about the polarity of the DC input.


----------

