Can smell burnt electrical

We have a 1996 Chevrolet Blazer 4.3 4WD standard vehicle, electric windows etc. The other night I smelled this scent that reminded me of when an electrical outlet is burning. Yesterday we had a dead vehicle. After replacing the battery and battery bolts when sitting I began to drive it home and noticed that under a load example lights on heater on etc. At a stop light the VoltMeter in the dash went down towards zero. This tells me it is most likely the alternator. However after asking the guy at the garage in which I left the vehicle running in the parking lot for a while, then on the way home at a stoplight I again put the same load on it and it didn't budge. Is this because even bad the alternator will still gave it a trickle charge? Should we replace the alternator? Thanks to those that will give their advice.