And if I don't have a "TH/ST" class device to compare readings with?
Even when you got one, it won´t bring you any further as they also can´t measure/displaying it correctly.
Example, mentioned before, the 10nF mica cap I´ve measured it with the ET4410, the U1733C from keysight and the ST2830 from sourcetronic.
All meters measured the capacity correctly inbetween their accuracies and inbetween the tolerance of the cap.
All meters measured the Xc correctly.
But none measured the
expected ESR correctly.
Expected means in this case the calculated one, based on the values of the Tan phi from the spec.
It should be in the range of appx 16ohms at 1khz.
The ET4410 displays appx 5 ohms, the ST2830 appx 3 Ohms and the keysight "freaks out", displaying something and blinking all the time.
The most probably reasons why you´ll find it here in this thread.
So for me there are several conclusions "avaible".
1.) Can´t expect to have it all even when you spend 1000 bucks or more for a LCR.
2.) The "secondary" measure functions of the "cheapos" (including the 1000 bucks or more) like D or ESR are (probably, will test it soon) trustable for caps with "bad" losses like electrolytic ones.
3.) When you wil get in a situation (as a hobbyist) to know exactly the losses/ESR of a high Q cap? Isn´t it more practical to know the ESR of a electrolytic cap which the meters could display trustable?
4.) Developers choosing a cap for their circuit design according to the specs of the manufacturer, not by measuring it before.
The only exception is to know the exact capacity (for filters) - And capacity every not too cheap meter can measure it correctly.
So why we private ones will go further...Buy a cap from a known manufacturer according to the specs it got and you need and that´s it.
5.) Knowing the exact ESR is in the most cases interesting by electrolytic caps (switching power supplies) when you must repair something. And the ESR of these ones even a cheaper meter should measure it.