• SolarKobo

Differences Between Pure Sine Wave And Modified Sine Wave

Updated: Jul 7, 2020

Most inverters in the Nigerian market are described as ‘pure sine wave inverter’. For those who have little or no technical knowledge of the science of inverters, but who need to know, the questions often are: On what basis are inverters classified as ‘pure sine wave’? What are the alternatives to pure sine wave inverters? What makes them a better choice for appliances than the alternatives? Et cetera.

A power inverter or inverter is an electronic appliance that converts DC (direct current) electricity from sources such as batteries or solar cells to AC (alternate current) electricity for use in appliances. As their names imply, they produce electric voltage in either direct or ‘alternating’ ways. In other words, alternating current describes the flow of charge that changes direction periodically and direct current describes the flow of charge that does not change direction but flows in one direction, mostly a straight line.

Their output waveforms are shown below.

DC output waveform
DC output waveform

AC output waveform.
AC output waveform.

Either of the two can be ‘modified’ or ‘rectified’ depending on the needs and nature of the appliances that use them.


Sometimes, the output voltage may require additional smoothing and adjustment to produce a uniform steady voltage. The DC output waveform can be modified in two ways, full-wave or half-wave as shown below.

The AC can be rectified or modified in these two ways, square or triangle.

Modified Square Wave