cfz2882
Well-known member
...mostly those meant for 6 or 12v automotive batts,but other types too 
Once saw an old 6 volt one at a rummage sale that was probably from the '40s that had a half wave tungar tube rectifier-probably quite a voltage drop across that tube. Some pre-1950s chargers used a copper oxide rectifier.Selenium rectifiers were the usual through the '50s and up to about 1989 in certain models. Silicon diodes began about 1961. Oldest charger i have in active use is a big one about 30 amps from 1966 and silicon diode. a 10 amp selenium one from 1979 and a couple recent 6 amp Schumacher ones that use a little switching power supply instead of a 60hz iron transformer-these little ones work very well,but are automatic and will not charge a 12v batt from all the way dead-only charges those up to 6v...
Once saw an old 6 volt one at a rummage sale that was probably from the '40s that had a half wave tungar tube rectifier-probably quite a voltage drop across that tube. Some pre-1950s chargers used a copper oxide rectifier.Selenium rectifiers were the usual through the '50s and up to about 1989 in certain models. Silicon diodes began about 1961. Oldest charger i have in active use is a big one about 30 amps from 1966 and silicon diode. a 10 amp selenium one from 1979 and a couple recent 6 amp Schumacher ones that use a little switching power supply instead of a 60hz iron transformer-these little ones work very well,but are automatic and will not charge a 12v batt from all the way dead-only charges those up to 6v...
