Magnetron with feed-through capacitor having a dielectric constant effecting a decrease in acoustic noise

A magnetron device provided with a filter circuit comprising first and second choke coils, each choke coil having a first end connected to a respective externally protruding lead for supporting a filament, and a feed-through capacitor, connecting second ends of said first and second choke coils,

• said feed-through capacitor being constituted of a dielectric ceramic material have a relative dielectric constant .epsilon..sub.s which satisfies .sqroot..epsilon..sub.s .ltoreq.50 and having an electrostatic capacity C in the range of from 100 to 300 pF, and each of said choke coils having an inductance L substantially equal to 1 .mu.H, to reduce sound pressure of an acoustic wave produced by said dielectric ceramic material without increasing the size of said feedthrough capacitor.

A magnetron device provided with a filter circuit, for suppressing leaking electromagnetic waves from the magnetron device, comprising first and second choke coils, each choke coil having a first end connected to a respective externally protruding lead for supporting a filament of the magnetron device, and a feed-through capacitor connecting second ends of said first and second choke coils, said magnetron device being of an alternating high voltage application type for driving by a commercial alternating power source, and said feed-through capacitor being constituted of a dielectric ceramic material having a relative dielectric constant .epsilon..sub.s which satisfies the requirement .sqroot..epsilon..sub.s .ltoreq.50 and having a capacitance in the range of from 100 pF to 300 pF, to reduce sound pressure of an acoustic wave produced by said dielectric ceramic material without increasing the size of said feed-through capacitor.