I need a simple way of dimming 12V Halogens

Jan 04, 2007 2 Replies

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nicholaslealand 19 years ago

I work with a preformance arts company doing shows in the scottish highlands and due to the massive amount of rain fall we need to use water-prof lighting.

We have been using 12v hallogens with some success but I cant find any pre-built 12v dimmers. I have found several that use 240v dimmers and then drop the voltage down to 12v but none so far that start with a 12v input.

My limited understanding of switch mode power suplys makes them seem like the logical solution but I dont know enough to pick the right chip.

I have found some that require only couple of external componets and only a small heat sink.

If someone could point me in the right direction it would save me a great deal of heart ache.

Thank you for your time. Nik

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Phil Allison 19 years ago

** Groper alert:

** Are you using 12 volt batteries or AC power ?

** It is generally not practical to *directly dim* 12 volt lights used in stage performances. Any dimming is done at the much higher AC supply voltage level.

The problem is excessive "voltage drop" in the cables feeding the lights. A voltage drop ( due to cable resistance and dimmer losses) of 5 to 10 volts in a 230 volt system has very little consequence, but in a 12 volt system it would be a disaster.

This is why you always see 12 volt halogen lamps sited very close to their step down transformers.

....... Phil

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Baz 19 years ago

You can buy tranformers (probably electronic) and dimmers (for the mains side) which are compatible. See you local lighting shop. I have some and they work ok.

Regards Barry

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