In Reply to: How can I convert AC voltage to DC voltage? posted by Hugh on 05/17/00 at 7:37 AM:
Simple. Buy a wall mount power supply that provides a low AC output voltage say 9 VAC. Now you will need to rectify the 9 VAC with a full wave bridge but do not add a filter capacitor. From the + output of the bridge go to the CW pin of a 10K multi-turn pot with the CCW pin at ground or the - pin of the bridge and take the wiper to the input of your recorder with the - pin of the bridge as ground to the recorder. Before you plug it in make sure that the pot is turned fully CCW. Now plug in the wall mount supply and use either the recorder or a DVM and set your full scale value.
For 110 volts you would set the pot for 1.10 VDC
The DVM and Recorder will provide averaging to the fullwave rectified AC from the bridge.
The reason you don't want a capacitor on the output of the bridge is to allow faster transients to pass.
A more accurate but hazardous method is to apply a low resistance shunt across the AC line and look for voltage drop across the shunt as an indication of delta V.