Hi Broomstick,
Boy do I know where you are coming from! I've got electrics sussed now, but with some difficulty! Could I suggest you investigate the RAF Training Manual for Electrics and/or the Oxford/Jeppesen manual on the same subject. Both would be good help I think. Get them at
www.transair.co.uk There was once a series of CD-roms on the JAA exams, which could have been by PPSC (but I have no specific knowledge on this) and they might have a Systems disk!
Good Luck anyway,
V=IR.. that's a good start!
Tucano