Thanks for the great explanation. I think it made a lot of things clearer and i hope i understand my problem now. I also read a little about transistors and made a new schematic :):
And again: Will this work?
I choose the resistors 220ohm, so the current on the base will be 20mA. Hope that will be enough to saturate the transistor.
Do you know any other transistors i could use, except "STX724/STX790A"?
I found some 2N5336, which can handle up to 5A, but i dunno how much base-current they need to be saturated.
And will the 1N4001 diodes be fine? They handle 1A average-current and 30A peak-current.
Thanks again