[TenTec] Re: wattmeter calibration

[Roy Koeppe]

 About,

"The problem comes with the loading that occurs when you connect a meter
across that RC pair. As the Handbook points out (at least, it used to!)
the metering circuit - DVM, VTVM, d-c voltmeter, whatever - will draw
current from the cap and act to reduce the average voltage that appears
across it. Even an 11 megohm VTVM will have this effect."


Not true in this case.  The old warnings about VTVM's loading down the
circuits and causing inaccuracies applies to extremely high Z circuits
only. Such as in a receiver's grid circuit, etc. This power measuring
device is very low Z with a big cap in the filtered output. The Z is
only a few ohms as compared to thousands of ohms in even a humble VOM.

No loading effect here at all to affect accuracy.

73,       Roy           K6XK




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