Capacitor Impedance is less than ESR?

"John KD5YI"

You have failed to realise the scales on the LHS are **ratios** - not actual values.

What the graphs show is that:

1. ESR is fairly constant above 2 kHz and depends mostly on temperature - ranging over 100:1 from -55C to +105C.

1. Impedance falls with rising frequency, but is limited by the series ESR value at any temperature.

..... Phil

"John KD5YI" schrieb im Newsbeitrag news:RJgnk.505$mP.222@trnddc03...

Hello John,

You may have overlooked the meaning of the plot.

Upper plot: Ratio relative to ESR @120Hz, 25° Lower plot: Ratio relative to impedance @120Hz, 25°

Impedance Z = 1/(jwC) + ESR

The ESR is only the resistive part(value) of the impedance.

At 120Hz, the value of 1/(w*C) is much larger than the ESR. That's why the ratio in this impedance plot has suich low values at higher frequencies.

Best regards, Helmut

You are absolutely right. Indeed I failed to read "ratio" and took it for absolute.

Thank you, Phil.

John

You are correct, too, Helmut. I failed to read "ratio" on the graph.

Thanks.

John