I read information about fluorescent lamp and compact fluorescent lamp (CFL) but I still don't understand why CFL saves energy and produce the same amount of light?
Maybe the electronic ballast consume less reactive power than the traditional ballast?
You question is not so clear but is seems that you're asking why is a modern compact CFL lamp more efficient that the old fashioned CFL tubes ?
This is easy to answer if you just sit down and think about it for a moment. What happens when something is inefficient ? Energy is lost, well not lost but it is converted into heat, not light. So something less efficient (tube CFL) will produce more heat than something more efficient (compact CFL).
Now what get's hot in the tube CFL ? The lamp itself, yes but this also happens for a compact CFL. What can get really hot is the magnetic ballast ! Also notice the size of such a ballast, it would not fit in a compact CFL ! So compact CFLs use an electronic load, which also does not get so hot so obviously it is more efficient.
In your tube CFL you could replace the magnetic ballast with an electronic one and so improve the efficiency.
Flouro lamps are actually more efficient at say 30KHz than 50Hz .The efficiency curve doesnt keep increasing ,it kind of limits out .This is why you tend to not see stuff in the MHz range despite it being technicaly feasible .The electronic ballast makes the tube itself more efficient .Even if you use rubbish for the electronics your overall efficiency should be better than a standard 50Hz ballast.
