Pure Sine Wave Inverters - puresunnergy.com

With a true/pure sine wave they accelerate in one direction until reaching top speed and then decelerate in the other direction until they stop and then they change direction and accelerate in that direcition until reaching top speend and then decelerate in the other direciton, ... The result is a very smooth movement as in the graph on the left above. The electricity you get from the power utility company is like this.

A modified sine wave, on the other hand, is not even a sine wave. It's really a modified square wave. In this case the electrons very rapidly speed up and continue at that speed and then rapidly speed up again and continue at that speed and then rapidly slow down and continue at that speed and then rapidly slow down again and then stop for a while. They then repeat all this in the other direction, ... The result is a very jerky movement as in the graph on the right above.
The problems

All appliances work with pure sine wave inverters. However, some may not work with modified sine wave inverters:

    may cause buzzing sound with some cheap stereos and ceiling fans;
    some digital clocks will not work;
    inductive motors, as found in some power tools, may not work properly.

The problem with pure sine wave inverter is that they cost more than modified sine wave inverters, anywhere from a few hundred to thousand dollars more. If you have a system for cottege use, you may be less picky in your selection of appliances but if the system is for your primary residence then you'll want a pure sine wave inverter.

PSI2000N Series pure sine wave inverter