The simplest switching scheme for the full-bridge converter produces a square wave
output voltage. The switches connect the load to Vdc when S1 and S2 are closed or
to Vdc when S3 and S4 are closed. The periodic switching of the load voltage
between Vdc and Vdc produces a square wave voltage across the load. Although
this alternating output is nonsinusoidal, it may be an adequate ac waveform for
some applications.