Compact fluorescent lights 1

[NEWFIEBOY]

Hi

I am looking for a dimmable compact fluorescent light source. I have a small portable fluorescent light which has a F4T5/C tube installed and runs on 4-AA 1.5 volt batteries and draws 400 ma. In addition to the batteries there is an external power supply plug for a 120 to 6 volt adapter. I connected an adjustable power supply to this plug and began to experiment with lesser voltages to see what would happen. I found that the lamp would not start at the lower voltages. It would start at 6 volt and would get progressivly dimmer as i reduced the voltage. I think that this light will work for the project i have in mind. My question is does anybody have any ideas on the long term affect of running these fluorescent tubes and ballasts at lower the design voltage?

 

[nbucska]

The way to dim it is to pulse the voltage and control the ON/OFF ratio. Dimming reduces the lifetime UNLESS you maintain the filament at the proper temperature.
Need more info? <nbucska@pcperipherals.com>

 

[jbartos]

Comment: The control of voltage on/off ratio downward will normally reduce the current through the filament, therefore, the lifetime will be reduced because of the lowered filament temperature. It appears that an indirect heating of filament will be the only way to maintain the normal lifetime.

 

[Trex77]

See NASA's web site for dimmable lighting ckt's. Used on the shuttle - 1000/1 ratio's and better.. Basically you need to increase the freq of the driving source as you reduce the amplitude. An IFD was in EDN or ED mag a while back... so a site search there may give you a ready to bulid ckt.

 

[jbartos]

Suggestion: Visit

http://www.thomasregister.com

and contact the fluorescent light dimmer manufacturers' reps for more/special info