Why are the Measured Values for RMS and MEAN of a Sine Wave Incorrect?

The waveform may actually not be a pure sine wave. Even though a 50/60 Hz sine wave is expected, the following factors may be involved:

  • The waveform is slightly distorted (harmonic components are mixed in)
  • Small amounts of harmonic noise are superimposed on the waveform
  • DC offset is superimposed on the waveform.

Related Products & Solutions

Mid Range

  • Power and Harmonic (THD) Measurements with Independent Range Controls
  • Efficiency measurements of AC/DC or DC/AC Inverters & Motors


Precision Power Analyzer WT3000

With 0.02% accuracy and 1MHz bandwidth, the WT3000 delivers where the highest precision measurements are required. It is the industry standard for R&D work on inverters, motor drives, lighting systems and electronic ballasts, UPS systems, aircraft power, transformer testing, and other power conversion devices.

PZ4000 Power Analyzer

The PZ4000 is designed for High Frequency Power Measurements as well as Transient Power Measurements. Its real-time acquisition system can perform cycle-by-cycle power measurements. One to Four input elements offer Basic Power Accuracy of 0.2% with 2 MHz Bandwidth and 5MS/sec digitizing rates.

WT1600 Digital Power Meter

The High-end WT1600 is designed for a wide range of applications, from energy-saving to large load applications. The WT1600 has a six element input capability to provide maximum flexibility, and Basic Power Accuracy of 0.1% with 1 MHz Bandwidth.

WT1800 High Performance Power Analyzer

The WT1800 Power Analyzer offers maximum flexibility with up to six wattmeter elements, high bandwidths, simultaneous high speed digitizing, and wide voltage and current ranges. Although this model is still available, the newer WT1800E offers higher accuracy.

WT2010/WT2030 Digital Power Meters

The WT2000 digital powermeter series has been designed with emphasis on basic performance (bandwidth, accuracy, response speed, and noise immunity) from the viewpoint of measurement of electrical quantities. The broad range of functions of these power analyzers enable them to be used in various fields of applications.

Power Analyzers and Power Meters

Measure characteristics of devices that generate, transform or consume electricity. Also called power meters or wattmeters, these devices measure parameters such as true power (watts), power factor, harmonics, and efficiency.