Dimmers change the shape of the AC wave by chopping off part of it. This reduces the power available to the LED bulb light, which becomes less bright. The terminology about dimmers can be confusing, such as ELV dimmer, MLV dimmer or Triac dimmer...
What does Triac dimmer mean?
The key electronic component in a dimmer that makes wave-chopping possible is called a "triac". So all these type of dimmers are "triac dimmers".
What`s Leading Edge dimming and Trailing Edge dimming?
When chopping a sine wave, you can chop the beginning of the wave, or the end of the wave. In both cases you achieve dimming by reducing the outgoing power. The more you chop, the dimmer the light.
So if the triac chops the beginning of the sine wave, it`s "Leading Edge" dimming. And guess what it`s called if you chop the end of the wave? Correct! "Trailing Edge".
What`s Forward Phase dimming and Phase dimming?
Forward Phase is another term for Leading Edge dimming. And, inversion Phase dimming is another way of saying Trailing Edge.
What`s an MLV dimmer?
MLV stands for Magnetic Low Voltage. It actually means it`s a dimmer for Magnetic Low Voltage lights.
Using 12 volt power at high current allowed halogen MR16s to be much brighter than if they ran from the 120 volt / low(-ish) current coming from the wall. The 12 volt conversion was easily achieved with a simple Transformer to reduce the voltage and increase the current. The combination of a 12 volt MR16 halogen bulb lights and a "magnetic transformer" became known as "Magnetic Low-Voltage" Lighting. Or MLV.
What`s an ELV dimmer?
"ELV dimmer" doesn`t mean the dimmer is electronic and low voltage, it means it`s for dimming an electronic Power Supply of a low voltage halogen light. An ELV dimmer cuts the trailing edge of the power wave, to reduce hum.
So ELV, Trailing Edge and inversion Phase dimming actually all mean the same thing.
Aren`t there any dimmers that can do both Leading Edge and Trailing Edge dimming?
Yes, they are usually called something like "universal dimmers", and they include a way to switch them from Leading Edge/Forward Phase/MLV to Trailing Edge/inversion Phase/ELV.
Is there such a thing as a Magnetic LED Driver/Power Supply?
Yes, we can make various dimmable Power Supplies for LED flexible strip which are mostly just a large transformer and a few other components. These are called "Magnetic" power supplies. They should be dimmed with leading edge/forward phase/MLV dimmers.