Magnetron power supply and control circuit

Claim 1

Electronic heating apparatus comprising metal wall structure defining a heating cavity, an antenna galvanically insulated from said wall structure and arranged to radiate microwaves into said heating cavity, a crossed-field discharge device including a pair of input terminals and a pair of output terminals, said device being characterized by the production of an a.c. voltage of ultra-high frequency across the output terminals thereof in response to the application of a d.c. voltage across the input terminals thereof, means capacitively coupling said output terminals respectively to said metal wall structure and to said antenna, a voltage converter including a pair of input terminals adapted to be connected to an associated low frequency a.c. supply source having a voltage in the general range of 110 to 125 volts and a pair of output terminals respectively connected to the input terminals of said device, said voltage converter further including four series-connected rectifiers, two input capacitors connected in parallel with the inner two of said rectifiers, two output capacitors connected in parallel with said four rectifiers, the capacitance of each of said input capacitors being twice the capacitance of each of said output capacitors, and a choke coil having an input terminal adapted for connection to the associated source of low voltage a.c. power and an output terminal adapted for connection to a first junction between said two inner rectifiers and to a second junction between said two output capacitors, said converter being characterized by the production of a d.c. output voltage across the output terminals thereof in response to the application of a low frequency a.c. input voltage across the input terminals thereof, the maximum amplitude of the d.c. output voltage from said converter being approximately four times the peak value of the a.c. input voltage to said converter.