This inverter uses a 12.6-V to 120-V transformer to deliver a quasi-sine wave that has the same rms and peak voltage
as a pure sine wave. Q1 to Q6 must be heatsinked. A 1.5" 4" aluminum heatsink was used on the prototype. The transformer should be a 3-A unit. The circuit uses feedback to help regulate the output voltage to 120 Vac. Notice that the output frequency is 75 Hz to avoid saturating the core of T1.