Calculator Inputs
Plotly Visualization
This chart compares ideal and loaded output, ripple, and recommended rating values.
Example Data Table
| Topology | Vrms | Stages | Capacitance | Load Current | Estimated Output | Ripple |
|---|---|---|---|---|---|---|
| Half-Wave | 120 V | 4 | 1.0 µF | 2 mA | 1307.6 V | 40.0 V |
| Full-Wave | 120 V | 4 | 1.0 µF | 2 mA | 1337.6 V | 20.0 V |
| Half-Wave | 230 V | 3 | 0.47 µF | 1 mA | 1882.7 V | 25.5 V |
Formula Used
Peak input voltage: Vpeak = Vrms × √2
Ideal no-load output: Videal = (2 × n × Vpeak) − (2 × n × Vd)
Half-wave ripple estimate: Vr(pp) ≈ [I / (f × C)] × [n(n + 1) / 2]
Full-wave ripple estimate: Vr(pp) ≈ [I / (2 × f × C)] × [n(n + 1) / 2]
Loaded output estimate: Vloaded ≈ Videal − sag drop − Vr(pp)/2
These formulas are practical approximations. Real circuits also depend on ESR, diode recovery, stray capacitance, transformer regulation, and layout quality.
How to Use This Calculator
- Choose half-wave or full-wave topology.
- Enter the transformer or source RMS voltage and frequency.
- Set the number of multiplier stages.
- Enter stage capacitance, expected load current, and diode drop.
- Optionally add a target output and ripple margin for design suggestions.
- Press the calculate button to view output voltage, ripple, power, and rating guidance.
- Use the CSV button for data export and the PDF button for a quick report.
Frequently Asked Questions
1. What does a voltage multiplier do?
It uses diodes and capacitors to build a DC voltage higher than the AC input peak. Designers use multipliers when current demand is modest but high voltage is needed.
2. Why does output drop under load?
Each stage charges and discharges through limited capacitance. As load current increases, ripple grows and the average output falls because stored charge is replenished imperfectly each cycle.
3. How is full-wave different from half-wave?
Full-wave arrangements refresh the capacitor chain more often. That usually cuts ripple and improves regulation for the same capacitance, stages, and load current.
4. Why is capacitor value so important?
Larger capacitance stores more charge per stage. That reduces voltage sag and ripple, especially when frequency is low or the load current is relatively high.
5. Can I keep adding more stages?
You can, but returns diminish. More stages increase output potential while also increasing ripple, charging losses, component stress, and sensitivity to leakage and parasitics.
6. What diode rating should I choose?
Use a reverse-voltage rating above the estimated peak inverse voltage with safety margin. Current rating, recovery behavior, and thermal limits also matter in real designs.
7. Is this suitable for final hardware validation?
It is a design estimator, not a replacement for bench testing. Validate actual waveforms, heating, insulation, leakage, and startup behavior before finalizing hardware.
8. Why include a bleeder resistor estimate?
High-voltage capacitors can retain dangerous charge after power removal. A bleeder resistor helps discharge the stack in a controlled way and improves safety during servicing.