John Denker is correct that the typical voltmeter reads zero if we set it to
AC and feed it a DC level. However, this is only true if the DC level is
truly DC. Hook a 1.5-volt battery to the voltmeter (set to AC) and it will
give a "temporary" reading. It initially responds to the change, and keeps
responding if the change keeps occurring (e.g. connect, disconnect, connect,
disconnect, etc.).
If the hot resistor and leads are producing a Seebeck voltage while being
torched, the temperature is not going to be anywhere near constant, the
voltage will be changing, the AC meter will read something. Readings of a
few millivolts do not surprise me.
Michael D. Edmiston, Ph.D. Phone/voice-mail: 419-358-3270
Professor of Chemistry & Physics FAX: 419-358-3323
Chairman, Science Department E-Mail edmiston@bluffton.edu
Bluffton College
280 West College Avenue
Bluffton, OH 45817