i have a silver beauty car battery charger that burned out the selenium rectifier how can i replace that rectifier with a silicone rectifier or how do i figure out what i need 8 volt output 6 amps d.c. a.c. input120 volts 60 hz 2.4 amps

 

The selenium rectifier has built in resistance that limits current flow, silicone rectifiers on the other hand have very low resistance in order to use one the least you need to do is have a hefty resistor in series to limit the current. By the time you buy a resistor and diode you may be better off to buy a new one.