Voltage loss of capacitor

[The Electrician]

Here is the result of a sweep of a Milspec hermetically sealed tantalum made by Texas Instruments. The ESR is about 204 milliohms at 100 Hz decreasing to 108 milliohms at 100 kHz. On the logarithmic scale used for the display, the ESR hardly seems to vary at all. This is probably the smallest variation I've seen:

Finally, here's a sweep of a 10 uF polycarbonate film cap showing moderate variation of ESR:

 

[JimB]

Real measurements on real components, great!

Thank you.

JimB

 

[danadak]

Thank you,

What's your comment on the following please,
it's saying ESR is not a frequency dependent !

From the capacitor guys -

https://www.mouser.com/pdfDocs/nichicon-impedance-versus-esr-white-paper.pdf

ESR is a f() of frequency.


Regards, Dana.

 

[The Electrician]

From the capacitor guys -

https://www.mouser.com/pdfDocs/nichicon-impedance-versus-esr-white-paper.pdf

ESR is a f() of frequency.


Regards, Dana.

That document says:
"ESR is very large at low frequencies, decreases very quickly as frequency increases, and continues to decrease at a much slower rate as frequency continues to increase"

This is not true for every kind of capacitor. Compare the sweeps I posted for the "Bumblebee" paper cap and the tantalum cap.

It's just not possible to make a blanket statement about ESR applying to all capacitors regarding how the ESR varies with frequency, other than to say that it does vary with frequency.

 

[danadak]

Totally agree Electrician. Both references have issues.

Regards, Dana.