Inverters: Sine wave vs modified sine wave – Which one is right for you?


An Inverteris an electrical device designed to support electrical appliances in case of power failure. The primary function of an inverter is to take direct current from the battery and convert it to alternating current that is required to run most of the electronic appliances.An inverter works using two types of technologies, a Pure Sine Wave technology and a Modified Sine Wave technology.

Pure Sine Wave:

A pure sine wave alternates voltage smoothly across zero volts, going up and down with rounded peaks.

Modified Sine Wave:

A modified sine wave instantly goes up for a few milliseconds then comes down to rest at zero for some milliseconds, and continues down the trough for a few milliseconds creating block-shaped signals.

Sine Wave Versus Modified Sine Wave Inverters:

  1. Usability:A modified sine wave inverter is used to power simpler electronic systems that do not have any audio video output or that contain fragile electronic parts.Using a modified sine wave inverter to power electronic appliances with audio/video output may produce distortions in the output or a buzzing sound.Sine wave inverters produce no distortions or buzzing sounds when powering electronic devices.
  1. Digital Clock:Electronic devices such as digital clocks do not operate correctly with a modified sine wave inverter.Time is incorrectly calculated with modified sine wave technology as opposed to a pure sine wave inverter.Also, modified sine wave inverters cannot charge batteries for cordless devices.
  1. Heating of Equipment:Some electronic devices work properly when powered by modified sine wave inverter, however, they tend to heat up as opposed to when run on a pure sine wave inverter.The life span of electronic equipment decreases due to heating.Thus, modified sine wave inverters can damage your delicate electrical appliances.
  1. Modern Appliances:Before buying a modified sine wave inverter,be aware that most modern day appliances do not operate properly or some do not operate at all on such type of inverter.You will need to have a sine wave inverter to have these modern devices function properly.
  1. Energy Consumption:Modified sine wave powered motors tend to heat up thereby consuming approximately 30% more energy than a sine wave inverter.
  1. Cost:Sine wave inverters tend to be more expensive than modified sine wave inverters because of their versatility and multi-functionality.However, with the advancements in technology, the prices of sine wave inverters are decreasing thereby making them affordable and highly preferable.
  1. Support for appliances:Sine wave inverter is more efficient than a modified wave inverter.Most appliances that run on sine wave but do not run on modified sine wave are:
  • Appliances with silicon-controlled rectifier such as automatic washing machines
  • Photocopiers, laser printers, and devices with thyristor
  • Some models of laptops
  • Battery chargers
  • LED TVs, CFL light bulbs that contain electronic ballasts
  • Pellet heaters, ovens, and electrical appliancesthat operate via microprocessor controls
  • Some medical equipment such as oxygen concentrators


Given the multiple advantages of sine wave inverters over modified sine wave inverters, most manufacturers of electronic appliances recommend using pure sine wave inverter as a battery backup to their devices.Therefore, it is advisable that you buy a pure sine wave model to allow a smoothand accurate functioning of all of your electronic devices.