A POWER SUPPLY FOR A MAGNETRON

摘要

PURPOSE:To enable a rated output to be retained with an input current immediately and automatically adjusted even at the time of activation and oscillation starting by changing a base value of the input current by an oscillator output voltage with a commercial power source input current controlled in a high-frequency heating oscillator driven with an inverter. CONSTITUTION:An output voltage detection part 17 and commercial power source input current detection part 9 are provided to a magnetron oscillator 6 driven with an inverter 7 composed of a power transistor. A detected current of the part 9 is compared to a current base 11 with a comparator 12. Then the output is made to an on/off pulse 15 with a comparator 13 and saw-tooth- wave generator 14, a turn on electricity time of the inverter 7 is controlled, and an input current is kept at a given value. On the other hand, the output of the part 17 is compared to the base value 19 with a comparator 20, and the output controls a transistor 23, and changes a value of the base value 12. This causes the input current to be changed so that a rated output is obtained concurrent with oscillation starting of a magnetron 6, and enables an occurrence of an excess voltage and electricity increase to be prevented.