Inverters: Modified sine wave vs. Pure sine wave

The main difference between pure sine wave and modified sine wave inverters is that the former produces a better and cleaner current. They’re more expensive, but for good reason.

So what are the advantages? There are several:

a) Output voltage wave form is pure sine wave with very low harmonic distortion and clean power like utility-supplied electricity.

b) Inductive loads like microwave ovens and motors run faster, quieter and cooler with pure sine.

c) Pure sine wave reduces audible and electrical noise in fans, fluorescent lights, audio amplifiers, TV, Game consoles, Fax, and answering machines.

d) Pure sine wave prevents crashes in computers, weird print out, and glitches and noise in monitors.

e) Pure sine reliably powers the following devices that will normally not work with modified sine wave inverters:

  • Laser printers, photocopiers, magneto-optical hard drives
  • Certain laptop computers (you should check with your manufacturer)
  • Some fluorescent lights with electronic ballasts
  • Power tools employing "solid state" power or variable speed control
  • Some battery chargers for cordless tools
  • Some new furnaces and pellet stoves with microprocessor control
  • Digital clocks with radios
  • Sewing machines with speed/microprocessor control
  • X-10 home automation system
  • Medical equipment such as oxygen concentrators

In short, pure sine wave inverters are better suited to sensitive electrical or electronic items such as laptop computers, stereos, laser printers, certain specialized applications such as medical equipment.

Modified sine wave works well for most uses, and they’re more economical. If you mostly want to run lights, TV, microwave oven, tools, a modified sine wave inverter is fine for your needs.

We’re often are asked if computers will work with modified sine wave. It's been our experience that most (with the exception of some laptops) will work (though some monitors will have interference such as lines or a hum).

We provide a full line of pure sine wave Inverters. To learn more, visit our Inverters section here.