View Single Post
Old 23rd Aug 2010, 8:52 am   #8
Mike Phelan
Dekatron
 
Mike Phelan's Avatar
 
Join Date: Nov 2003
Location: Near Leeds, West Yorkshire, UK
Posts: 4,609
Default Re: Old car radio - how to change polarity?

Quote:
Originally Posted by Herald1360 View Post
Quote:
Originally Posted by murphyv310 View Post
It must have a dynamo as alternators are for negative earth.
Except for a few Lucas 10AC or 11AC types with separate control gear. I don't know about foreign makes......
Ah - but the diodes in the alternator are still the same way round, so what murphy310 still stands.
Quote:
The big picture is not clear, but it's not unlikely for a vintage car enthusiast to have an old radio (+ve earth) that he wants to use in a more recent car.
AFAIK there were no vintage (that's pre-1931) cars fitted with radios.

Back to the original question, easier to change the radio, and the fact that quite a few old car radios allowed the polarity to be reversed.
__________________
Mike.
Mike Phelan is offline