Rectifier DC Output Calculator

Estimate rectified DC output from AC input: choose rectifier type, set diode drops, optional smoothing capacitor, and load.

How to Use

  1. Enter the AC input as RMS voltage and frequency.
  2. Select the rectifier type (half-wave, full-wave center-tap, or bridge).
  3. Set diode forward drop (and how many diodes conduct per half-cycle is handled by the mode).
  4. Optionally enable a smoothing capacitor to estimate ripple and average DC.
  5. Enter a load (resistance) to estimate current and power.
Waveform View
AC input → rectified output → optional capacitor smoothing.
Vpk
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Vdc
—
Iload
—
Vripple
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Status: —
Voltage Time Blue: AC input Orange: Rectified Red: Smoothed (cap) Vpk
Tip: Enable the smoothing capacitor to estimate ripple. Results are approximate and intended for quick sizing checks.
Inputs & Settings
Enter AC RMS + select rectifier. Optional capacitor for ripple estimate.
Examples: 12Vac transformer, 120Vac mains, 230Vac mains
Typical: 50Hz or 60Hz
Bridge uses two diode drops per conduction path.
Silicon ~0.7–1.1V, Schottky ~0.2–0.5V (varies with current)
Used to estimate load current and power (approx).
When enabled, ripple is estimated using ΔV ≈ I / (C · fripple).
Examples: 470µF, 1000µF, 2200µF, 4700µF
Show Work (step-by-step)
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Work is shown using base units for clarity (V RMS, V peak, A, Ω, F, Hz).

Rectifier Formulas (Quick Reference)

This tool uses common approximations for fast estimates. Real results vary with transformer regulation, diode curves, ESR, and load behavior.

  • Peak from RMS: Vpk = Vrms × √2
  • Diode drops: Vpk_out ≈ Vpk − (N × Vd)
  • Ripple frequency: half-wave fripple = f, full-wave/bridge fripple = 2f
  • Cap ripple (approx): ΔV ≈ Iload / (C × fripple)
  • Load current (approx): Iload ≈ Vdc / Rload

FAQ

Why is bridge DC lower than expected?

A bridge has two diode drops in the conduction path. Under load, drops increase with current and transformer voltage may sag.

What does the smoothing capacitor actually do?

It charges near the peak and supplies current between peaks, reducing ripple. Ripple depends heavily on load current and capacitance.

Is the ripple formula exact?

No—ΔV ≈ I/(C·fripple) is a common estimate assuming relatively constant load current and small ripple compared to peak voltage.

Center-tap vs bridge: which is “better”?

Center-tap full-wave uses one diode drop but requires a center-tapped transformer. Bridge is simple and common but has two diode drops per path.

Tool Info

Last updated:

Updates may include better ripple modeling, unit support, waveform visualization improvements, and edge-case handling.