How does this CCFL inverter work? Answered
I have this CCFL (Cold Cathode Fluorescent Light) inverter from a scanner. it powers the scanner light.
That's the schematic, but I can't see all the components very good, I'm sure about everything that's noted in the schematic, but I don't know the value of that capacitor between both collectors. It's that brown one from the picture.
So the question is:
How does this circuit work?
I'm still trying to figure out how the transistors switch, it's really weird, because when I try recreating this on my breadbord it doesn't work.
And why is the first coil shorted out?
What I do know about this is that it has an output voltage (very low current, serveral micro amps) of 2 to 3kV. It also works at a very high frequency, about 30kHz I think, and it has a ferrite core transformer. The primary windings are very thick, and there are about 10 turns. the secondary has Many windings, a few thousand.
The primary current is limited by the frequency (Xl = 2*Pi*f*L) so high frequency means high resistance of the coil, and that means a low current.
now how does the switching process work? and what's the use of the brown capacitor?