I was thinking the capacitive divider was to reduce the C loading of the voltmeter on the resonant circuit, but it's to reduce the input resistance.

I remember a maxim, "when you measure something, you change it" It is officially called the "Observer affect" from the wiki, regarding electronics, (I think it is incomplete and needs more work)
"In , and are usually wired in series or parallel to the circuit, and so by their very presence affect the current or the voltage they are measuring by way of presenting an additional real or complex to the circuit, thus changing the and behavior of the circuit itself. Even a more passive device such as a , which measures the wire current without coming into physical contact with the wire, affects the current through the circuit being measured because the ."

?My real world experience is with High Q coils for the AM band, about 240uh with Qs over 1400 at 800khz. This is an R of 1,600,000 at resonance. putting a 10MΩ resistor in parallel lowers that to 1,379,310, this would cause a 14% reduction in the Q measurement.


? The above measurements and coil are wound on 6" polystyrene pipe couplers, TPI where cut on a thread cutting setting lathe.

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