Calculate peak or DC voltage in a half-wave rectifier from the other value using Vdc = Vpeak/π or Vpeak = Vdc×π, with results in V, mV, or kV.
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Half Wave Rectifier Voltage Formula
The calculator uses the ideal average DC output voltage formula for a half wave rectifier. It assumes an ideal diode and no filter capacitor.
- Vdc = average DC output voltage of the half wave rectifier
- Vpeak = peak value of the input AC voltage
- π = pi, approximately 3.1416
If you enter the peak voltage, the calculator divides it by π to find the average DC voltage. If you enter the DC voltage, it multiplies it by π to find the required peak voltage. The unit selectors convert millivolts, volts, and kilovolts before applying the formula, then convert the answer back to the selected output unit.
Half Wave Rectifier Voltage Reference
| Peak Voltage | Average DC Voltage | Calculation |
|---|---|---|
| 5 V | 1.5915 V | 5 ÷ π |
| 12 V | 3.8197 V | 12 ÷ π |
| 24 V | 7.6394 V | 24 ÷ π |
| 100 V | 31.8310 V | 100 ÷ π |
The values below show the unit conversions used before the voltage formula is applied.
| Unit | Meaning | Value in Volts |
|---|---|---|
| mV | millivolt | 0.001 V |
| V | volt | 1 V |
| kV | kilovolt | 1000 V |
Example Problems
Example 1: Find DC voltage from peak voltage
You have a half wave rectifier with a peak voltage of 12 V.
The average DC voltage is approximately 3.8197 V.
Example 2: Find peak voltage from DC voltage
You need an average DC voltage of 10 V from an ideal half wave rectifier.
The required peak voltage is approximately 31.4159 V.
FAQ
Is this the same as RMS voltage?
No. This calculator uses average DC voltage for a half wave rectified sine wave. RMS voltage is different. For an ideal half wave rectifier, the RMS output voltage is Vpeak ÷ 2, while the average DC voltage is Vpeak ÷ π.
Does the formula include diode voltage drop?
No. The formula is for an ideal diode. In a real circuit, the diode forward voltage drop reduces the output voltage. A silicon diode often drops about 0.7 V when conducting, but the exact value depends on the diode and current.
Why is the DC voltage lower than the peak voltage?
A half wave rectifier only passes one half of the AC sine wave and blocks the other half. Since the output is zero for half of each cycle, the average DC value is much lower than the peak value.