"A" Circuit (3.0L Only)
WARNING: This page is about a different car, the 2004 Mazda Tribute, 2003 Mazda Tribute, and 2002 Mazda Tribute. However, it is still accessible from the selected car via links, so may be relevant.
The "A" circuit or battery sense circuit is used to sense battery voltage. This voltage is used by the regulator to determine generator output. This circuit is used to supply current to the generator field (rotor). The amount of current supplied to the rotor will determine generator output.