Crackle Wrote:ppppenguin Wrote:Mike, while much of your explanation makes sense, this bit does not. ESR and leakage are different things. Leakage can be often be modelled as a parallel resistance, but cannot, by its nature be a series one.
So am I right in assuming that Electrolytics can have both ESR and leakage properties then, otherwise if it was just ESR it would not display leakage properties, i.e. passing DC current...
Yes. Both exist (all capacitors, actually, but electrolytics are more noticeable).
Leakage results in the capacitor slowly discharging over time, instead of just sitting on the shelf and staying at the voltage they were left at - or, putting it another way, passing a bit of DC in a circuit. It can be modelled, crudely, as Equivalent Parallel Resistance.
ESR - Equivalent Series Resistance - stops the capacitor's impedance from falling towards zero as frequency rises. It's the resistance if the leadout wires; the resistance of the metallising in film capacitors, and in electrolytics, the significant resistance of the electrolyte (which we'd like to be a perfect conductor, but unfortunately isn't).
ESR is what makes a capacitor get warm when it is passing lots of ripple current in a power supply, and it's why manufacturers put a limit to this.
