Cold Cathode lights can be left on continually?

[ChefJoe]

Not really sure if this is a general hardware or case-mod thing, but I hope it's close enough that I'll get an answer all the same.

Just put in a cold cathode light and was wondering if these things can be left on continually (it is a flourescent light afterall) when the computer is powered up or if I need to put a switch on it and only leave on for so many hours at a time. I recall a post where someone said he left his on continuously and it broke in the middle, but that doesn't make any sense to me.

Thanks for any answers you may have.

 

[fatbaby]

theory: cold cats get pretty hot hot hot, heat causes stuff to expand, thus weaking it. Eventually it will bend slightly and when it cools, it may crack

Just for the sake of our power, turn it off when "you're done"

 

[mrCide]

they have 15,000 hours of life.. and they dont get that hot, they get warm if anything..

hope you were joking fatbaby

 

[fatbaby]

<< they have 15,000 hours of life.. and they dont get that hot, they get warm if anything..

hope you were joking fatbaby >>



well my cold cat gets pretty hot! I decide to leave it on for 8 hours, outside of my case, and i touch it...ouch!

 

[Syborg1211]

fatbaby- you sure those are really cold cathodes? heh jk, if you have good ventilation in your case your light wont even get warm or hot to the touch...

 

[RagManX]

<< theory: cold cats get pretty hot hot hot, heat causes stuff to expand, thus weaking it. Eventually it will bend slightly and when it cools, it may crack >>


As others have said, a cold cath shouldn't be hot. The name of them comes from the fact that they don't run hot. If yours is getting hot, you either didn't get a cold cath, or got a defective one.

RagManX

 

[Jeff7]

Ragmanx has a good point. I just headed on over to howthingswork.com and searched for cold cathode. Though their search engine needs tweaking (got results on the Cold War) I found some info on Cold Cathodes. They make a good point too - LCD's like in laptop screens use CC tubes for backlighting. I've got an LCD right here on my laptop, and it isn't warm at all. Plus, according to the site, "In addition to providing ample light, CCFLs do not rise far above the ambient temperature."

 

[Jerboy]

As others have said, a cold cath shouldn't be hot. The name of them comes from the fact that they don't run hot. If yours is getting hot, you either didn't get a cold cath, or got a defective one.

RagManX

The name cold cathode has nothing to do with whether the whole tube runs hot or not. "cold cathode" could mean starting type and/or tube construction.

Cold cathode tubes are desgined to be started without pre-heating electrodes and continues to run without thermionic emission.(cold cathode start and operation) They have cylindrical electrodes made of iron. Slimlines are started without pre-heating electrodes(cold cathode starting), but once it's started, the coiled filament gets hot enough to create thermionic emission(hot cathode operation).


One thing in common is that both cold cathode and slimline takes a high voltage to strike, but slimline is easier to start. Coiled filament electrodes in slimlines have coating on them, so it takes less voltage than cylindrical electrodes.

Most older fluorescent fixtures rely on thermionic emission starting. Filaments are pre-heated, then when the filaments are hot enough, thermionic emission allows starting without an application of very high voltage.
PIC, cold cathode slimline driver
Take a look and compare between slimline and cold cathode