Analyze capacitor ripple current using practical engineering inputs. Review ESR stress and filter behavior instantly. Get faster design checks with exportable results and charts.
| Case | Capacitance per Capacitor (µF) | Ripple Vpp (V) | Frequency (Hz) | ESR (Ω) | Parallel Count | Waveform |
|---|---|---|---|---|---|---|
| Rectifier Filter Bank | 470 | 1.2 | 100 | 0.08 | 2 | Triangular |
| Switching Supply Output | 220 | 0.35 | 50000 | 0.03 | 3 | Sinusoidal |
This calculator estimates capacitor ripple current from the entered ripple voltage, capacitance, and ripple frequency. It also extends the calculation to ESR stress, loss, reactance, stored energy, and rating margin.
C(total) = C(single) × N
ESR(total) = ESR(single) ÷ N
I(bank,rms) = 2 × f × C(total) × V(ripple,pp)
V(ripple,rms) = V(ripple,pp) ÷ (2√2)
I(bank,rms) = 2π × f × C(total) × V(ripple,rms)
Xc = 1 ÷ (2πfC(total))
V(esr) = I(per cap,rms) × ESR(single)
P(esr) = I² × ESR
Q = C(total) × V(ripple,pp)
E = 0.5 × C(total) × V(dc)²
Use the triangular option for rectifier-like discharge and recharge behavior. Use the sinusoidal option when ripple more closely follows a sine-shaped AC component.
This tool helps compare a single capacitor against a capacitor bank, estimate current sharing, and identify whether ESR heating or rating margin may become a design concern.
Ripple current is the alternating current component flowing into and out of a capacitor while it smooths or filters a varying voltage. Designers often check it because excess ripple current can raise internal temperature, accelerate electrolyte drying, increase ESR over time, and reduce service life.
In many power stages, ripple frequency depends on the source. A full-wave rectifier usually creates ripple at twice line frequency, while a switching converter produces ripple related to the switching rate and control behavior. Higher frequency can reduce voltage ripple for the same capacitance, but ripple current and ESR loss still need review.
Parallel capacitors can improve performance by increasing total capacitance and lowering effective ESR. Even so, good layout and similar component values matter. Current sharing becomes less predictable when parts are mismatched, wiring resistance differs, or temperature changes move ESR away from the assumed value.
The graph included on this page shows how the estimated ripple current changes with frequency while other entered values stay fixed. That makes it easier to see whether a design window is narrow or forgiving. The export tools also help when documenting design checks for reviews, reports, and comparison studies.
Ripple current is the AC portion of current that repeatedly charges and discharges a capacitor. It creates internal loss through ESR and can raise temperature, which affects reliability and life.
ESR converts ripple current into heat. Even moderate current can produce noticeable loss when ESR is high. Lower ESR usually improves efficiency and reduces thermal stress in filter applications.
Use the triangular model when the capacitor voltage rises and falls approximately linearly during each ripple period, such as many smoothing and reservoir situations after rectification.
Use the sinusoidal model when the ripple component is closer to a sine wave. This often fits small-signal AC analysis or filtered waveforms with smoother periodic behavior.
It usually helps by increasing total capacitance and lowering effective ESR. However, layout resistance, tolerance spread, and thermal variation can reduce equal current sharing in real hardware.
Rating margin compares the estimated ripple current per capacitor against the entered rated ripple current. Positive margin means headroom remains. Negative margin means the estimate exceeds the rating.
No. It is a fast engineering estimate. Final design decisions should still check manufacturer ripple current limits, temperature derating, lifetime curves, impedance data, and actual operating waveform shape.
Stored energy helps evaluate startup behavior, hold-up capability, and discharge safety. It does not directly set ripple current, but it is useful when reviewing the capacitor’s overall operating role.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.