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parasitic coil capacitance from frequency

Zak28

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Sweeping a coil with generator measured a coils voltage peaking at ~30.7Mhz and dipping at ~14Mhz - its inductance is ~4mH.

Does this mean its parasitic capacitance is 6.71 fempto farads?
 
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FvM

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Can't be answered without knowing the complete measurement circuit.
 

CataM

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Another way is to apply fast rising edge step voltage and measure the ringing.
 

FvM

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Parasitic coil capacitance refers to parallel capacitance, I presume. Thus you are looking for the parallel resonance of the unloaded coil. The best approach for unloaded resonance measurement is a weakly coupled grid dip meter or an equivalent setup.

The fact that your measurement shows two resonances makes clear that your setup isn't a simple LC parallel circuit but some kind of LCC or LLC circuit. And most likely parasitic parameters of the measurement setup are falsifying the original resonance frequency.
 

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