Inline Resistor for LC Filter Power Measurements

[wardenclyffe]

Hey guys,

I stumbled across this article when I was trying to figure out how to measure component power --> http://www.anandtech.com/show/6529/busting-the-x86-power-myth-indepth-clover-trail-power-analysis. Basically, they seem to suggest that you can measure the power consumption of different components by inserting a small value resistor inline with their input LC filters. My guess is that you would have some sort of switching regulator providing a voltage to an output LC filter that would smooth it into DC for the component in question. They say that by measuring the voltage drop across the resistor, you can figure out how much current is flowing into the component and thus how much power it is consuming.

I tried this method myself, but both my multimeter and oscilloscope seemed to say the voltage differential was 0 across the resistor (resistor value was 5mohm). I thought about it and I was wondering if the series inductor is going to make it such that the RMS voltage is always 0 across the resistor. I tried switching the coupling on the oscilloscope but that didn't see to make any difference. What am I doing wrong? Let me know if you have any thoughts.

Thanks!!