Author Topic: Shunt Measurement of Capacitor ESR and Resonance Frequency with a VNA  (Read 2695 times)

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Offline graybeardTopic starter

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    • Chris Grossman


In this video I describe how to measure capacitor  ESR (Equivalent Series Resistance) and resonance frequency using a vector network analyzer.   I show my homemade fixture, describe in detail how the measurements are made, demonstrate several examples, and show how to convert the S21 measurement to ESR.   Any VNA that covers 100KHz to 1GHz can be used.

Here are printable versions of the |S21| to ESR conversion graph and conversion table.

. . . Chris
« Last Edit: June 25, 2020, 04:22:03 pm by graybeard »
 
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Offline graybeardTopic starter

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In this video I demonstrate ESR and resonant frequency and of some sample capacitors using the NanoVNA-F.  The results are consistent with my previous measurements using the Siglent SVA1015X VNA.

This is a quick supplement to my previous video  "0012 Measurement of Capacitor ESR and Resonance Frequency with a VNA (Vector Network Analyzer)."  If you want to see more details about the fixture, why this measurement works, and more example measurements please see my previous video
 
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Offline bob91343

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This all neglects ESL, which can by itself account for the tiny spike on the screen.
 

Offline graybeardTopic starter

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This all neglects ESL, which can by itself account for the tiny spike on the screen.


Just how does this neglect ESL?  The series resonance of the capacitor is frequency at which the reactance of the ESL and the reactance of the C are equal in magnitude, but have opposite signs and cancel.  I specifically discussed it in the first of the two videos.
 
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Offline cdev

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*Thank you!*

I may be able to use a bnc to banana plug adaptor as a test fixture if I can find a noninductive (50 or 75 ohm?) resistor to use as my "load" - For through hole components, it would likely be better than some other means to testing these aspects of inductance and capacitance (LCR meter that tests at much lower frequencies)
« Last Edit: July 08, 2020, 10:16:38 pm by cdev »
"What the large print giveth, the small print taketh away."
 


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