The quality of the AC current that the inverter produces in waveform, frequency, and voltage, determines the types of appliances and equipment it can operate. A waveform is a graphic representation of the shape that indicates the wave s frequency and amplitude. The frequency is the rate at which something occurs over a specified period of time. Amplitude is the measured height above or below a reference point. In an AC waveform the reference point is zero volts.
Inverters produce one of three basic types of waveforms.
The horizontal line represents zero volts. A modified or quasi sine-wave looks like the side view of a set of steps. A square wave looks like two adjacent squares. One of the squares is above the zero volt line, the other is below it. As with a sine wave, for half of the cycle the voltage is positive, and for the other half of the cycle it is negative.