Alternator Pains

Dana67Dart I am not real smart and I have a 75 Dart Sport that isn't charging . I have power on blue wire to alternator 12 volts and ground on green wire . I had a spare voltage regulator and tried it , same thing, not charging . I know with todays questionable new parts it is possible but is it possible both voltage regulators are bad or am I not understanding correctly ? Any help is greatly appreciated