Calculator Input
Example Data Table
| Waveform | Known Input | Peak | RMS | Peak-to-Peak | Notes |
|---|---|---|---|---|---|
| Sine | 325.00 V peak | 325.00 V | 229.81 V | 650.00 V | Common mains peak example. |
| Square | 12.00 V peak | 12.00 V | 12.00 V | 24.00 V | Peak equals RMS for an ideal square wave. |
| Triangle | 15.00 A peak | 15.00 A | 8.66 A | 30.00 A | Uses RMS = Peak / √3. |
| Full-Wave Rectified Sine | 100.00 V peak | 100.00 V | 70.71 V | 100.00 V | Minimum value remains zero. |
Formula Used
The calculator first converts the selected input into a peak value. It then applies waveform specific crest factor rules to derive RMS, peak-to-peak, average rectified value, and optional load power.
| Case | Formula |
|---|---|
| Generic RMS | RMS = Peak ÷ Crest Factor |
| Sine | RMS = Peak ÷ √2 |
| Square | RMS = Peak |
| Triangle | RMS = Peak ÷ √3 |
| Sawtooth | RMS = Peak ÷ √3 |
| Half-Wave Rectified Sine | RMS = Peak ÷ 2 |
| Full-Wave Rectified Sine | RMS = Peak ÷ √2 |
| Peak-to-Peak | Bipolar waves: Peak-to-Peak = 2 × Peak. Rectified waves: Peak-to-Peak = Peak. |
| Average Rectified Value | Sine and full-wave: 2 × Peak ÷ π. Half-wave: Peak ÷ π. Triangle or sawtooth: Peak ÷ 2. |
| Power Into Load | Power = RMS² ÷ Resistance |
How to Use This Calculator
- Select the conversion mode, such as Peak to RMS or RMS to Peak-to-Peak.
- Choose the waveform type because RMS depends on waveform shape.
- Enter the known input value using the unit you want displayed.
- Use custom crest factor only when your signal does not match a standard waveform.
- Add frequency if you want a reference label for the plotted signal.
- Enter load resistance to estimate power from the calculated RMS value.
- Choose the number of decimal places for the displayed results.
- Press Calculate Now to show the result above the form and update the chart.
- Use the CSV or PDF buttons to export the current results.
Frequently Asked Questions
1. What is RMS in electrical engineering?
RMS is the effective value of a varying signal. It represents the equivalent DC value that would deliver the same heating or power effect into a resistive load.
2. Why does waveform type matter?
Signals with the same peak value can have different RMS values. A square wave, sine wave, and triangle wave distribute energy differently over one cycle.
3. When is peak-to-peak more useful than peak?
Peak-to-peak is useful when you measure total excursion on an oscilloscope. It directly shows the difference between maximum and minimum waveform values.
4. What is crest factor?
Crest factor is the ratio of peak value to RMS value. It helps describe how sharp or impulsive a waveform is compared with its effective level.
5. Can I use this for current signals?
Yes. The calculator is unit agnostic. Enter A, mA, or another current unit in the unit field, and the displayed outputs will use that label.
6. Why is power optional?
Power needs both RMS voltage and resistance. If resistance is unknown or the quantity is not voltage, the calculator leaves the power output as not available.
7. What does custom crest factor mode do?
Custom mode lets you model nonstandard signals using your own peak-to-RMS ratio. It is useful for pulsed, clipped, or specialized laboratory waveforms.
8. Is this suitable for oscilloscope checks?
Yes. It is useful for quick engineering checks when converting between measured peak or peak-to-peak readings and expected RMS values during testing.