https://nalar.dev/tags/esr/ Recent content in ESR on Nalar Hugo en-us Mon, 01 Jan 0001 00:00:00 +0000 https://nalar.dev/electrolytic-capacitor-esr-ripple-current-heating/ Sat, 19 Sep 2026 00:00:00 +0000 https://nalar.dev/electrolytic-capacitor-esr-ripple-current-heating/ <p>An aluminum electrolytic capacitor does not behave like an ideal capacitor. Its internal foil, electrolyte, tabs, and contacts add resistance, represented in a simple model as equivalent series resistance, or ESR. When AC ripple current flows through that resistance, the capacitor dissipates real power as heat.</p> <p>For power-supply filtering, this mechanism can matter as much as capacitance and voltage rating. A capacitor may have the expected number of microfarads and still run too hot if its ESR is too high for the ripple current imposed by the circuit.</p>