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statjunk
09-28-2007, 05:39 AM
Without getting overly technical, how do the dimmers work that allow you to run incandescent or hallogen using the same switch?

Why haven't they incorporated low voltage?

Thanks

Tom

jimbo
09-28-2007, 06:10 AM
Not sure of your question, because halogen lights ARE incandescent lights.

Any dimmer has a designed operating voltage and current spec. Many dimmers cannot be used on fluorescent, and even those that can, you must have a special dimmable rated bulb/ballast.

Spaceman Spiff
09-28-2007, 06:56 AM
It's easy to make dimmers for standard incandescent (resistive) loads. With a little more work a manufacturer can make one that will deal with the harmonics and inductance that a switching power supply (found in most LV halogen fixtures) places on the line side. The other part of the equation is to get a power supply for LV lamps that can deal with dimmed line input.
Most dimmers are a "zero crossing" triac type. They turn on the current at a certain time in the power cycle and it automatically turns off when the voltage crosses zero volts.
I suspect the type you have for the LV lamps is a "variable crossing type". This is (if I remember correctly) a MOSFET based system that can switch on and off the current at any time, regardless of the timing of the cycle. This allows an internal timer to turn on and off the current at different ratios to output different power levels.
in both cases the residual heat in the filament evens out all the ons and offs so that we can't tell that they are there.

Now arc lamps... that's a different matter, for a different day.

geniescience
09-28-2007, 08:14 AM
bulbs made to be dimmed. 110V. Using the 110 Volt current. So they can use the same circuit as other bulbs, like the old style incandescent ones we have seen for generations.

That may be the simplest answer to tell you why they haven't made use of DC low volts.
Halogen bulbs that don't use low voltage, use regular house current.
Bulbs like MR16, GU10, and T4 bulbs can take 110 volts. AFAIK.
There is no transformer.

That may be the answer you wanted.
On the other hand, i don't know whether you were asking about a specific dimmer called "Duo ..."

david