I'm not sure if your bridge rectifier is in the alternator or the regulator; however, you can unplug the regulator from the alternator and meter across the alternator post and look for +20+- volts on AC or DC scale. No voltage says bad alternator, +20+- says bad regulator, AC or DC reading gives the location of the rectifier, which changes voltage from AC to DC. It's usually a bad regulator.