Compact Fluorescent Lamp

Most likely it's due to the time it takes for the mercury in the tube to become fully vaporized. Mercury vapor in the tube emits UV light that excite the visible light phosphors coated on the glass. The vapor has to come to a certain level for the tube to operate at maximum output. When the tubes have been off and cold, some of the vapor condenses to liquid mercury which takes time to fully vaporize when warmed up.

Not when it's a light that you are going to keep on for a decent amount of time. Which realistically where such bulbs best serve. A light that is being turned on for only a few brief minutes, maybe even less, won't be an environmental issue, so a CFL won't make a real difference. But lights that stay on, like an office ceiling light or the light over the front door, the slow turn on (and even slower when it's cold) won't matter, but the lower current drain and longer life will be a significant advantage there.

Michael

mowhoong wrote: > When you turn the CFL on, It will take about 40 sec brighten fully , > which make it very inconvenient to use. > Can any members help me to explain this phenomenon ? Thank You. >

Wow. I haven't had a crappy CFL like that in years. At the time it was a Philips lamp. All the cheapos from Home Depot are at full brilliance immediately - at least it's so subtle I don't notice it if they're not. Those Philips lamps OTOH were very dim at first.

G=B2

Depends on brand and model. I know some that are as close to 'instant on' at close to full brightness as you could reasonably expect. It does get worse as they age though.

You're either talking about old technology ones or very cheap crap.

I buy Philips or Osram (Sylvania in the USA IIRC).

Graham

Modern Philips ones in the UK are fine. 20 years or so ago I remember it being a problem.

Graham

Wow. I haven't had a crappy CFL like that in years. At the time it was a Philips lamp. All the cheapos from Home Depot are at full brilliance immediately - at least it's so subtle I don't notice it if they're not. Those Philips lamps OTOH were very dim at first.

Their " Ambiance " range ( which look juts like normal peal bulbs) are all very slow - ie, several minutes to reach full output on a cold morning. The initial light level is about the same as one candle.

No use in a kitchen or bathroom - at all.

..... Phil

"Eeysore"

Buy a Philips "Ambience" CFL and see just how horribly slow they are.

..... Phil

Even with a room temp of 20C they take about 3 minutes.

..... Phil

When you turn the CFL on, It will take about 40 sec brighten

All the cheapos from Home Depot are at full brilliance immediately - at least it's so subtle I don't notice it if they're not.

Cos the tubes are just loaded with mercury and the heater filaments are overdriven to hell.

They tend to go " booom " real quick too.

... Phil

That's not what they sell here.

I have had EXCELLENT results with Philips CFLs. In fact almost all of mine are and have been Philips or Osram. I reckon I got 15,000 hrs out of one of them.

Graham

Haven't seen those ones. At least not that style by Philips.

What is interesting now is the different colour temp phosphors you can get up to ~ 6400K. They're harsh for home lighting but good for technical work.

Graham

I bought 3 cheapos too. Similar results. Maybe they're more generous with the mercury ? Not had one go bang though.

Graham

Snipping FUCKHOLE !

You whine about others doing it but you're the arch-expert.

Grahgm

Well you won't find them in Morrisons.

Graham

I snipped a few, completely irrelevant, words.

" Monstrous Ego = Zero Honesty " needs to be chiselled on this asshole's tombstone.

...... Phil

"Eeysore"

What a desperate & PATHETIC LIAR !!!

What a desperate & PATHETIC SNIPPER !!!

...... Phil

Yes you did. The words that placed my comment in context.

STOP IT !

Graham

The fact you can't find them in a major retailer ?

GET A LIFE.

Graham

They are readily available from many retailers, world wide.

What a desperate & PATHETIC LIAR !!!

What a desperate & PATHETIC OVER SNIPPER !!!

...... Phil