20 WATT FLUORO INVERTER used tip3055This circuit will drive a 40 watt fluoro or two 20watt tubes in series.
The transformer is wound on a ferrite rod 10mm dia and 8cm long.
Do not remove the tube when the circuit is operating as the spikes produced by the transformer will damage the transistor.
The circuit will take approx 1.5amp on 12v, making it more efficient than running the tubes from the mains. A normal fluoro takes 20 watts for the tube and about 15 watts for the ballast.
source : http://talkingelectronics.com/projects/200TrCcts/200TrCcts.html