AC to DC voltage calculator

This calculator converts AC RMS voltage to DC voltage for a full-wave rectifier circuit with a smoothing capacitor.

Input Parameters

Calculation Results

Calculation Formula

VDC = VAC × 0.9 × (1 - e-t / (RC))

Where:
VDC = DC output voltage
VAC = AC RMS input voltage
C = Smoothing capacitor in Farads
R = Load resistance in Ohms
t = Time after rectification (typically 1/120s for 60Hz AC)

Maximum DC Voltage:

Average DC Voltage:

Ripple Voltage:

AC to DC voltage calculator Calculator Usage Guide

Learn how to use the AC to DC voltage calculator and its working principles

How to use the calculator

  1. Enter the AC RMS voltage of your source (e.g., 120V, 230V).
  2. Specify the capacitance of your smoothing capacitor. A typical value is 470μF for a 12V system.
  3. Enter the load resistance (the device you're powering).
  4. Click the "Calculate" button to see the estimated DC output values.
  5. Click "Reset" to clear all inputs and start over.

Working Principle

This calculator is based on a simple full-wave rectifier circuit with a smoothing capacitor. When AC voltage is converted to DC, a capacitor stores charge during the peaks of the AC waveform and releases it during the valleys, creating a more stable DC voltage.

The calculator provides three important values:

  • Maximum DC Voltage: The peak voltage of the DC output.
  • Average DC Voltage: The typical DC voltage you would measure.
  • Ripple Voltage: The AC component superimposed on the DC voltage (this is what the capacitor smooths out).

Example Application

Suppose you have a 12V DC power supply that you want to build using a transformer and bridge rectifier:

  • You might use a transformer that outputs 15V AC RMS.
  • You could use a 470μF capacitor (0.00047F) for smoothing.
  • If your load requires 1000Ω resistance, the calculator shows these values:
    • Maximum DC: 13.5V
    • Average DC: 9.5V
    • Ripple Voltage: 1.2V

Note: This calculator assumes a full-wave bridge rectifier and does not account for diode drops or other losses in the circuit. For precision applications, consult an electronics engineer.