Switching inverter with sine wave output

Claim 1

Apparatus for producing a sine wave output voltage from a DC input voltage comprising: an inverter; a sequencing circuit coupled to said inverter; a switching circuit comprising a plurality of bidirectional switches coupled to said sequencing circuit and said inverter for producing said sine wave output, said switches being triggered by said sequencing circuit; and an output load coupled to said switching circuit for receiving said sine wave output; wherein the improvement comprises: A/C means for supplying an alternating current (A/C) voltage which is coupled to said sequencing circuit; said sequencing circuit comprising a plurality of stages coupled together in a series manner such that each stage is triggered on, only, when the previous stage has just previously been conductive and when said A/C voltage changes polarity; each of said stages comprising an SCR having an anode connected to one end of a load which produces a signal to trigger said bidirectional switches, said anode being connected to a first lead of an isolated capacitor which charges to a potential when said SCR is conductive; a second lead of said capacitor being coupled to the gate of the next stage''s SCR; said potential on said capacitor desposing said next stage''s SCR to become conductive upon the changing of the A/C voltage polarity; said SCR and said next stage''s SCR being desposed to conduct on opposite polarities of said A/C voltage.