#100

This tutorial video shows how to estimate / measure the self-resonant frequency (SRF) of a capacitor using an oscilloscope and a signal generator. It builds upon topics presented in two previous videos:

LC Resonant Circuits:
   • #55: Back to Basics: Tutorial on LC R...  

Capacitor and inductor self-resonance:
   • #56: Basics of Capacitor & Inductor s...  

The video also mentions some caveats to be aware of when attempting this. In addition to those mentioned in the video, there are more... The parasitic inductance of the fixture and probe should be substantially lower than the parasitics of the capacitor under test. For small RF capacitors, well under 1nF for example, this is especially important. Special RF fixtures would be needed to accurately measure the SRF.

There are several other factors that can influence this measurement, but the basic concept works well for capacitors used for DC bypassing, broadband signal coupling, etc. For RF applications, it is much more difficult to apply this method and get accurate results.