hi i need a diagram for a cicuit to keep a car 12v supply constantly at 12v as accuratly as is possible. The input voltage 11.8 -15.8vdc is way to wide to give accurate engine managment opperation. The particular circuit i need to supply has a 10 amp fuse. im guessing this would also be the rated max throughput for the circuit. ive seen various 12vdc stabilizers on the market but they appear to be basically caps that take spikes out which isnt really what im after. I need this to be a constant 12vdc output voltage regardless of input from say 12vdc - 18vdc. any help would be greatly appreciated. please no maybe replies i need a definitive answer thanks in advance