1996 Geo Tracker Battery not charging

I have recently replaced both altenator, battery, and terminal ends. The battery still runs down. I have checked for power drains with a 12 volt test light. Discovered the radio was draining my battery. Fixed that by removing the radio. Had the charging system checked again. The technician told me that the voltage regulator had failed. I was under the impression that the voltage regulator was part of the alternator? I don't see anything in engine compartment that resembles a Voltage Regulator. I looked online for visual and find no information on a, location. The picture of a Voltage Regulator looks like it is on the back of the alternator. Can you help me out.