High-frequency heating equipments divide into two main types: (1) those used for dielectric heating, and(2) those used for induction heating. The induction heating equipments again divide into seven types: (1) commercial power line; (2) rotary generator; (3) mercury-arc-converter; (4) gaseous-tube converter; (5) mercury-hydrogen-spark-gap converter; (6) quenched spark-gap converter; (7) vacuum-tube generator. Dielectric heating equipments in general use a vacuum-tube oscillator as a source of radio-frequency power ranging in frequency from 2 megacycles to hundreds of megacycles. At frequencies above about 200 megacycles,the power is generated by devices other than a conventional vacuum tube, such as a magnetron, Klystron or other microwave device. A dielectric heating generator is normally a high-voltage generator, and application requires high-voltage radio-frequency matching techniques. An induction heating generator is essentially a high-current device operating into very low impedance circuits and sometimes requires transformation in the load circuit to provide the desired heating effect.

High-frequency heating equipments divide into twomain types: (1) those used for dielectric heating, and(2) those used for induction heating. The induction heatingequipments again divide into seven types: (1) commercialpower line; (2) rotary generator; (3) mercuryarcconverter; (4) gaseous-tube converter; (5) mercuryhydrogenspark-gap converter; (6) quenched spark-gapconverter; (7) vacuum-tube generator.Dielectric heating equipments in general use a vacuumtube oscillator as a source of radio-frequency powerranging in frequency from 2 megacycles to hundreds ofmegacycles. At frequencies above about 200 megacycles,the power is generated by devices other than a conventionalvacuum tube, such as a magnetron, Klystron or othermicrowave device. A dielectric heating generator is normallya high-voltage generator, and application requireshigh-voltage radio-frequency matching techniques. Aninduction heating generator is essentially a high-currentdevice operating into very low impedance circuits andsometimes requires transformation in the load circuit toprovide the desired heating effect.