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ESR Calculator
Estimate capacitor ESR effects including ripple current loss, ESR voltage ripple, capacitive reactance, total impedance magnitude, and thermal rise estimate.
Input Parameters
Results
Equations Used
ESR Power Loss = Iripple² × ESR
ESR Ripple Voltage = Iripple × ESR
Capacitive Reactance = 1 / (2πfC)
|Z| ≈ √(ESR² + Xc²)
Temperature Rise ≈ Power Loss × Thermal Resistance
Frequently Asked Questions (FAQ)
Q1: What is ESR?
ESR is equivalent series resistance inside a capacitor and causes ripple loss and heating.
Q2: Why does ripple current heat a capacitor?
Ripple current dissipates power in ESR according to I²R.
Q3: Is lower ESR always better?
Usually for power filtering, but stability, damping, and regulator requirements may set a minimum ESR range.
Q4: Does ESR change with frequency?
Yes. Datasheet ESR values are frequency and temperature dependent.
Q5: Can this predict capacitor lifetime?
No. It estimates loss and temperature rise; lifetime requires manufacturer endurance models.
Q6: Does this include ESL?
No. At high frequency, equivalent series inductance can dominate and should be checked separately.
