Re: what does the rectifier do on a 1979 merc
Not to be flip, but the rectifier on a '79 Merc does exactly the same thing that the rectifier on a battery charger does.
A Bridge rectifier like on the Merc is a matrix of diodes. Diodes are one way electrical gates. As AC voltage is supplied to the rectifier, these diodes send all the postive voltage components to a common connection, and all the negative voltage components to a common connection, thus changing AC voltage to DC Voltage.
