Rectifier Smoothing Capacitor Calculator

Capacitor value from load current, ripple and frequency.

Values

Load current (mA) Allowed ripple ΔV (V) Rectifier Mains frequency (Hz)

Result

C ≈ 5000 µF

Smoothing capacitor sizing

After rectification the capacitor charges to the peak and supplies the load between peaks. The required value keeps ripple inside your budget: C = I / (f_ripple·ΔV), where f_ripple is 100/120 Hz for full-wave or 50/60 Hz for half-wave.

Example: 500 mA, 0.5 V ripple, full-wave 50 Hz → C = 0.5 / (100·0.5) = 10 mF? No — 0.5 A / (100 Hz · 0.5 V) = 0.01 F = 10000 µF. Use ≥ 1.5× voltage rating and low-ESR types for power supplies.