RMS Calculations

by Brad Suppanz

Some typical periodic power supply waveforms are shown below.


Below is a live web calculator that you can use to find the RMS, DC, and AC components of waveforms. Just enter the values to desribe a waveform based on the figures above.

Enter V1 or I1: 
Enter V2 or I2: 
Enter the duty cycle, D:  (where D is between 0 and 1)

RESULTS:
(a) Pulse Waveform:
RMS = V1*SQRT(D) = 
DC = D*V1 = 
AC = SQRT(RMS^2 - DC^2) = 

(b) Triangle Waveform:
RMS = SQRT((I1^2 + I1*I2 + I2^2)/3) = 
DC = (I1 + I2)/2 = 
AC = SQRT(RMS^2 - DC^2) = 

(c) Trapezoidal Waveform:
RMS = SQRT(D*(I1^2 + I1*I2 + I2^2)/3) = 
DC = D*(I1 + I2)/2 = 
AC = SQRT(RMS^2 - DC^2) = 

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Written 12/16/97
Last updated 7/20/2004 
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