Here is a simple 12 volts DC to AC inverter circuit. This 120V AC power source is built with a simple 120V:24V or 110V:24V center-tapped control. Aspencore network. News & Analytics ... Schematic of ...

In an initial test, this circuit was able to efficiently convert AC currents into DC signals at liquid helium temperatures (e.g., those attained using closed-cycle refrigeration techniques).

Vectors and Vector Diagrams applied to the Alternating Current Circuit. By W. Cramp C. F. Smith. Pp. xvi + 252. (London: Longmans, Green and Co., 1909.) ...