AC Voltage Calculator
AC Voltage Terms
- Peak Voltage (VPK) The maximum instantaneous value of a function as measured from the zero-volt level. For the waveform shown above, the peak amplitude and peak value are the same, since the average value of the function is zero volts.
- Peak-to-Peak Voltage (VPP) The full voltage between positive and negative peaks of the waveform; that is, the sum of the magnitude of the positive and negative peaks.
- RMS Voltage (Vrms) The root-mean-square or effective value of a waveform, equivalent to a DC voltage that would provide the same amount of heat generation in a resistor as the AC voltage would if applied to that same resistor.
- Average Voltage (Vavg) The level of a waveform defined by the condition that the area enclosed by the curve above this level is exactly equal to the area enclosed by the curve below this level.
- RMS is not an "Average" voltage, and its mathematical relationship to peak voltage varies depending on the type of waveform.
- The RMS value is the square root of the mean (average) value of the squared function of the instantaneous values.
- Since an AC voltage rises and falls with time, it takes more AC voltage to produce a given RMS voltage than it would for DC. For example, it would take 169 volts peak AC to achieve 120 volts RMS (.707 x169).
- Most multi-meters, either voltmeters or ammeters, measure RMS value assuming a pure sinusoidal waveform.
AC Voltage Formulas
- VPK = 0.5 x VPP
- VPK = 1.414 x Vrms
- VPK = 1.571 x Vavg
- VPP = 2 x VPK
- VPP = 2.828 x Vrms
- VPP = 3.141 x Vavg
- Vrms = 0.707 x VPK
- Vrms = 0.353 x VPP
- Vrms = 1.111 x Vavg
- Vavg = 0.637 x VPK