ok, but in the orignal circuit the SCR discharge the capacitor on de high voltage cooil , and in this circutit the cooil is exchanged but the irf740. no??
Because is used Q1?????'
Yes you are right the original circuit dicharged the voltage through the coil.In this circuit the cap is charged and the IRF740 just grounds one side of the coil. you could replace the IRF740 with a SCR.I have done it and its works the same. You can just use a voltage regulator and the original circuit.