What's the difference between a CFL and a CCFL?

[eem2am]

What's the difference between a CFL and a CCFL?

 

[mishra12]

A CFL, or compact fluorescent lamp, is a type of fluorescent lamp intended to replace traditional incandescent lamps. Advantages of CFL's include lower power use, a longer rated life, and significantly lower greenhouse gas emission. However, these lights tend to have higher purchase prices than those of incandescent alternatives. A CCFL, or cold cathode fluorescent lamp, is any type of fluorescent lamp in which the cathode is not independently heated. Neon lights are common examples of CCFL's.

 

[Orson Cart]

Neons don't need the fluorescence though as the mixture of gases at low pressure give the colour, CFL's and CCFL's need the fluorescent (white) coatings on the inside of the glass to turn the UV light created into visible white (and some other colours) light, CFL's contain mercury vapour to assist in their operation which is lost to the environment (not in a good way) when they are thrown away...
Regards, Orson Cart.

 

[J_M]

CCFL's are much more energy efficient, last longer and can be dimmed by simply lowering the voltage. CFL's require expensive dimmable ballasts.

 

[Orson Cart]

Given that CCFL's are a negative resistance load in their region of normal operation (i.e. if you lower the volts the current goes up) how does lowering the voltage across the terminals of a CCFL give a dimming effect when the same power is consumed?
Regards, Orson Cart.

 

[J_M]

You don't - you reduce voltage on the primary of the inverter.

I guess I could have been more clear but I assumed that most people understand that when discussing CCFL,CFL lighting as a lighting system that the discussion includes the ballast/inverter.

 

[Orson Cart]

So you are relying on the inverter to control the current in the tube?, which is how dimming is really achieved (at least the only stable way) but you were unfortunately giving an alternate impression to readers who are not familiar with the true characteristics of these lighting tubes and who may be endeavouring to design their own ways to control them...
Regards, Orson Cart.

 

[J_M]

Where did I give any design advice? Where was any asked for? I gave a direct answer to the question asked. I was not asked for a technical explanation on how dimming CFL or CCFL was done. Since you don't seem to be a moderator I will just assume you are being pedantic.

 

[Orson Cart]

Surely this forum is all about design advice to those who are trying to learn essential concepts and techniques?
Regards, Orson Cart.

 

[J_M]

Surely this forum is all about design advice to those who are trying to learn essential concepts and techniques?
Regards, Orson Cart.

I thought it was an electronics discussion forum but OK , I'll bite. Assuming what you say is correct and that you are the self appointed protector of accuracy then how do you explain that the first post you made after mine was an overly wordy sarcastic question pretending that I implied you dim the lamp rather than a post containing the information you believed should have been clarified? I can see that you would rather try to showcase yourself than than help people "learn essential concepts and techniques" as evidenced by the fact that you would rather derail the OP's thread making such a post instead of making a constructive post adding additional information or clarifying mine. Since you seem to prefer that approach I will no longer be replying to your posts.

 

[eem2am]

.....and this is exactly why this forum is so excellent...

...because it doesn't give you the drudgerous, dull advice delivery that is found in classical theory books!..

..we get sharp debate, which involves flames now and again , but this adds entertainmant to the learning process, which is much needed when i've just spent 3 drudgerous , dull , dismal hours clicking and waiting for a huge number of dull, dry PhD type theses downloaded on fluorescent lighting.

Please keep it up.

And i am into the dimming idea now, ..........these posts have cemented for me that dimming is done by adjusting the lamp current....and that this can be adjusted by adjusting the primary voltage.............

superb guys!


keep it up.