A control unit for a magnetron, the circuit being supplied form a source of
a.c. voltage and comprising a power switch, a process controller/firing
circuit for the power switch and first and second transformers. The first
transformer supplies a desired filament voltage to the magnetron and the
second transformer controls the current flow in the magnetron and hence
the power output. The second transformer is controlled by the operation of
the process controller/firing circuit and the power switch to provide an
infinitely variable power output setting to the magnetron.
