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Power Supply Ripple Calculator
Calculate the ripple voltage on a rectified supply for a given capacitance and load, or the capacitance needed for a ripple target.
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Math & Science
Power Supply Ripple Calculator
Frontend preview — no upload or external service.
Ripple result
500 mA into 2200 µF on a full-wave 50 Hz rectifier gives about 2.3 V peak-to-peak ripple. For 1 V ripple you would need roughly 5000 µF.
How the Power Supply Ripple Calculator works
- Enter the load current the supply must deliver, at its maximum rather than typical.
- Set the capacitance, or set a ripple target and solve for it.
- Check the minimum voltage at the ripple trough still exceeds what your regulator needs to stay in regulation.
The method
The capacitor discharges into the load between rectifier peaks, and the voltage it loses in that gap is the ripple.
V_ripple ≈ I ÷ (f_ripple × C), with f_ripple = 2 × mains frequency for a full-wave rectifier
At 0.5 A, 100 Hz ripple frequency and 2200 µF: 0.5 ÷ (100 × 0.0022) ≈ 2.3 V peak-to-peak.
FAQ
Why is the ripple frequency double the mains frequency?
Because a full-wave rectifier produces a peak on both halves of the cycle. That halves the discharge time compared with a half-wave rectifier, which is why full-wave needs far less capacitance for the same ripple.
What ripple is acceptable?
It depends on what follows. A linear regulator needs the ripple trough to stay above its dropout voltage; without a regulator, the ripple appears directly in your output and in anything sensitive downstream.
Does a bigger capacitor always help?
It reduces ripple and increases the inrush current at switch-on, which stresses the rectifier and can trip breakers. Very large smoothing capacitors often need an inrush limiter.
How we compare
| Feature | Online Tool Store | A graphing calculator | A stats package |
|---|---|---|---|
| Solves in both directions | ✓ | Manual | ✓ |
| Ripple frequency handled | ✓ | Assumed | Yes |
| Shows the formula | ✓ | ✗ | Sometimes |
| Circuit simulation | ✗ | ✗ | ✓ |
Power Supply Ripple Calculator checks the ripple trough against regulator dropout, which is the number that decides whether the supply actually works.