Energy saving lightbulb

[sPoNiX]

Has anyone yet invented a Compact Fluorescent bulb that will operate off a standard dimmer switch?

sPoNiX

[John Laird]

Recent threads here would suggest they are dim enough...

If you need serious dimming, I doubt a normal incandescent bulb will be using much power anyway. The dimmer unit only itself dissipates a small amount of waste heat.

[Dave Plowman]

*No* fluorescent will work off a standard dimmer switch properly - you require special dimmers and ballasts.

[sPoNiX]

We have energy saving lightbulbs all over except for the bedrooms. They are on 100% most (But not all) of the time so it'd be nice to have CFLs but as the bedrooms have dimmers we have a problem.

In this day and age I'd have thought it simple to build a dimmable CFL that works on a dimmer switch!

All I have seen are dimmable CLFs that dim using an on-off-on flick of the light switch but not one that works on a dimmer!

sPoNiX

[John Laird]

It appears to be possible, but various Google'd articles suggest that the dimming must be in the light fitting itself. I think you have to have some adjustable ballast (this being the thing that stops the electrical flow in the excited gas simply running away unstoppably in the first place). Simply chopping off negative-going waveforms (as a external dimmer does) won't work.

Put simply, a dimmer switch is designed to work with an incandescent light, which as a simple glowing filament doesn't care about what heats it. Give it less power somehow/anyhow and it glows less.

[sPoNiX]

But there is no reason one couldn't be made that does operate off a standard dimmer. Yes, the circuitry would have to be a bit clever and the end product would be more expensive but I can see ways it could be done.

The question is has anyone already done it?

sPoNiX

[John]

On a slighty different tack, is it advisable to use a dimmer switch on 12V halogen downlighters or should I stick with the traditional on off switch? Which gets me thinking, as we get switches in 'one gang one way, two gang one way' etc. is a single blanking plate a no gang no way ;^)

TIA

John

[BillV]

And even then the control range isn't very large .... you 1/2 dim the light, then it goes out..

[Ian Stirling]

The light output by a incadescent bulb goes as something like the fourth power of voltage. At half power, the brightness is a fraction of a percent of normal.

[Dave Plowman]

I've got some Osram electronic dimming chokes where the range is much greater than that. Cost an arm and a leg, though.

[Dave Plowman]

Well, given that it hasn't already, I'd say there would be too many snags.

If you run standard switch start florries off TV studio dimmers they can be dimmed to a degree, but of course have to be started on max.

[N. Thornton]

Why not move to CFL that uses separate tube and control gear, such as PLC or 2D. Then you can fit a pot to the drive circuit to effect dimming. Note you should use 2 pin bulbs for this, not 4 pin. Running

4 pinners underpower shortens their life significantly.

The other option, which is a bit frowned on by purists, but I've seen it work ok, is to use a standard flupresecent fitting and put it on a variac to dim it. I wonder if you could do that with a standard CFL, perhaps. In fact even a series pot might even work, though it would get hot.

Regards, NT

[G&M]

[G&M]

Yes. But the bulbs aren't commercially available yet. Probably 9-12 months I think.

[G&M]

It wasn't so much the snags, more that the circuitry wouldn't fit in the space under the bulb. A new BCDMOS IC is being designed to solve the problem.

[Andrew Gabriel]

Products have been available for years in the US. No idea why no one sells them in UK. It's almost a case of just removing the DC smoothing capacitor from the switched mode PSU.

[Andrew Gabriel]

Even a conventional dimmer and ballast can easily dim through the whole range. See some notes of mine Don Klipstein lifted from old Usenet postings: "Dimming fluorescents 4" on

[Andrew Gabriel]

Been around in the US for some years. I suspect there's no perceived market in the UK (there's not much for this in the US, even though there is a larger market for very many more types of retrofit compact fluorescent than there is in the UK).

[The Natural Philosopher]

I don't want one with a dimmer. I want one with a BRIGHTENER.

So called 60W equivalent about as much use as a guttering candle.

[N. Thornton]

hehe. Halogens can be dimmed, but with the following downsides:

1. the bulbs may not last as long, depending on the exact cycling used.
2. they become much less energy efficient. So yes you can, but it is normally better to switch the lights individually to obtain the light level you want.

Regards, NT