On Tue, 03 Oct 2006 23:59:13 GMT VWWall wrote: | Frank White wrote: |> I would think it is a simple matter of a current probe and a voltage |> probe, one on each channel and measuring the offset to calculate |> the phase angle. |> |> Is this a reasonable method given that your probes are properly |> calibrated? | | Put the "voltage" on the vertical and the "current" on the horizontal. | You'll get a 1:1 Lissajou figure. If the scope's axis gains are equal, | two sine waves in phase will show a line at 45 degrees. At 90 degreees | they will form a circle. Phases in between will form an ellipse, from | which you can calculate the phase angle. | | As has been noted, this will only work correctly with sine waves.
But you can still see the variations between voltage and current with this method. It just won't be directly easy to figure out specifically what is happening is your voltage is not a sine wave. But with a voltage sine wave and harmonic currents, it should be rather obvious.