LTspice: Computing the Average or RMS Value of a Trace

The LTspice waveform viewer can integrate a trace to produce the average or RMS value over a given region.

To integrate a trace in the waveform viewer:

  1. Zoom in to the region of interest.
  2. Hold down the control key and click the label of the trace you want to integrate.

Based on the physical units of the data trace, LTspice IV displays a meaningful average for that type of data. For example, if the units are a voltage or current, LTspice IV displays the average and the RMS values. Otherwise, LTspice IV displays the average and integral of the data displayed in the waveform viewer. If you are plotting noise densities from a .noise simulation, LTspice IV shows total RMS noise.



Gabino Alonso

Gabino Alonso is currently the Marketing Manager for the Power by Linear™ Group. Prior to joining Analog Devices Inc., Gabino held various positions in marketing, engineering, operations and education at Linear Technology, Texas Instruments, California Polytechnic State University, and Cabrillo College. He holds a Master of Science Degree in Electrical & Computer Engineering from University of California, Santa Barbara.