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What kind of device can measure a coil's self resonance frequency?
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Ben321:
I know, that the inter-winding capacitance of an inductor, combined with its inductance, gives every coil its own resonant frequency. What is the best way to measure this? Can measurement for this be easily made with the L and C settings of an LCR meter, and then manually calculate the resonant frequency? Or could it be made even easier with a device that's designed to measure resonance of an inductor? Does such a device exist? If so, what is it called?
David Hess:
At resonance the inductor appears open, so a sine wave frequency sweep of any kind plus an AC voltage measurement can find the self resonant frequency quickly.  This is essentially what a scalar or vector network analyzer would do and that might be required for a small inductance where the self resonant frequency is high.  For the inductors I typically deal with, I just use my function generator and oscilloscope which works to 1s of MHz if not 10s of MHz.  A measurement of phase will provide higher accuracy but seems silly since self resonate frequency is not well controlled in typical inductors.

An LCR meter would need variable frequency operation.  Measurements of the impedance at three frequencies should allow calculation of the self resonate frequency for a simple inductor, but the math is not trivial.
G0HZU:
Note that there will be more than one resonance within a typical solenoid. At work I do a lot of wideband RF design and it can be challenging to design something like an ultra wideband high pass filter for example.
A typical solenoid has transmission line properties so it can also act as a fairly good short circuit at much higher frequencies. This is usually what limits the upper frequency range of a high pass filter for example. At high frequencies the passband will develop steep notches in the response. The length of the winding in each shunt inductor in the high pass filter gives a good clue as to when it will begin to show a reflection coefficient of close to 1 at 180degrees where it mimics a shorted halfwave transmission line and it crowbars the filter at this series resonance frequency. This causes the unwanted notches in the passband. At even higher frequencies this transmission line behaviour produces even more resonances.
Henrik_V:
I use two transistors (TUN or TUP)  (Peltz-oscillator) and a counter...
https://wiki.analog.com/university/courses/electronics/comms-lab-peltz-osc
not very precise due to the miller cap, but ok for me

any negative resistance circuit  that matches the load ...
http://www.zen22142.zen.co.uk/Theory/neg_resistance/negres.htm


another circuit I also tried for this :
https://www.mikrocontroller.net/topic/436039
easy readout of the needed negative resistance
 

just don't add the additional capacitor ...   
G0HZU:
A nanovna would usually be the best tool for stuff like this in terms of price vs performance. They can be purchased for about $40 (USD) online.
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