Need ESR clarification

[Mosaic]

On the matter of ESR:

these ESR curves:
**broken link removed**

Match what i see with my ESR meter. As frequency rises ESR drops generally.
Now what I am curious about is whether the ESR has to do with the rise times? A 1Khz freq. will show a poor ESR for a 100nF ceramic cap. But a 1Mhz freq. shows much better ESR.
In a1 Khz pulse application, is the ESR governed by the frequency or the RISE time (<100ns) of the pulse.?

In the ESR ratings of caps.....@ what freq & wave shape is used for testing, is there a standard?

 

[Norator]

Do you mean this formula?
Rise time in nS = 350/(bw in MHz) so a scope with 700 Mhz bw should have a 10% to 90% risetime of 1/2 nS.

 

[Nigel Goodwin]

In the ESR ratings of caps.....@ what freq & wave shape is used for testing, is there a standard?

Yes, it's 100KHz sinewave - ESR measurement generally applies to electrolytics, and is the major cause of their failure.

 

[Mosaic]

It seems that ESR is dependent on dielectric and frequency. Otherwise it would just be the innate series resistance of the physical construction of a cap and not vary with frequency like impedance does. Is it true to say that when resonance occurs in a cap. then the remaining resistance is the ESR?