Andre Abelian wrote:
>
> Hi to all engineers,
>
> I apologize if the tag isn't right.
> I do not know how many of you use UV light for
> drinking water filtration specially to filter (H. Pylori)
> bacteria. I have setup with 9 pieces of different filters and the last
> one is the UV light. My problem is that the light is always
> stays on and it burns every 7-8 months. According to
> report continuously leaving it on the UV light will last longer
> then turning on and off. What I am thinking is to dim the light
> when it is not used instead of turning it off BUT the question
> is How to dim it.? Does any one know how to dim fluorescent light?


Hi Andre, first, what is failing in the tube??
If the end filaments are failing, you can use a
tube driving circuit that does not require the
end filaments, like the one on this page:
http://centauri.ezy.net.au/~fastvid/tube4w.htm

Generally fluoro tubes are glass cannister filled
with gas, and will last almost forever if kept
cool. Overheating tends to break the end filaments,
as does starting them up too many times.

Have you measured the tube temperature (near the
ends) when running and if so what is it?

Re your question about "dimming" you can simply
reduce the tube running current by using a different
ballast or a series resistor, as long as the tube
still starts reliably. :o)
-Roman

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