Originally Posted by Sephiroth

I just noticed that you don't have the D1 diode marked in the schematic??? I was just wondering cos I have got my dual coil working fine now but have included a 1N4001 per transistor...

I can't find any where that says what this diode is for but am i right in guessing that when the power coil fires, its magnetic field induces a current in the trigger coil in the opposite direction to the current induced by the magnets and thus quickly turns off the transistor as soon as it opens which creates the sharp pulsing? So this diode allows the "backwards current" to flow freely while forcing the induced current from the rotor into the transistor.