[Amps] Dummy Loads & Wattmeters

Dr. David Kirkby david.kirkby at onetel.net
Thu Dec 3 13:46:11 PST 2009


Alex Eban wrote:
> ...a very old method was to use a thermocouple heated by a resistor equal to
> the load (usually 50 ohms). Then the thing was heated with DC until the
> thermocouple's output equaled the RF generated signal. The DC power was
> easily measured to a 1 of 2 percent precision and both were equal. In
> addition the arrangement was able to measure the true RMS value of the
> signal; this didn't matter if the  signal was single frequency but the
> inherent precision was there. 

Be aware, RMS power is a useless unit. You can compute the RMS power of an RF 
signal, but it is no practical use whatsoever.

Dave



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