| 摘要 |
PROBLEM TO BE SOLVED: To perform stable operation without being practically influenced by noise by operation of the inverter part by making a comparison in the timing before resonance voltage equivalently becomes zero voltage by extracting a trigger on the basis of a result by comparing a waveform by coupling the resonance voltage in AC with DC voltage. SOLUTION: The control part for controlling the inverter part compares a signal detecting an AC component of resonance voltage generated in a resonance circuit composed of a heating coil 5 and a capacitor 6 with comparing DC voltage being in an amplitude range of a detected signal to generate a trigger on the basis of the comparing signal to reset an oscillating period of a self-traveling oscillator, and also compares an output signal of the self- traveling oscillator with DC voltage for setting ON time of a switching element 7 to output an ON/OFF signal of the switching element 7. Here, when proper voltage in amplitude of a signal detecting an AC component is set as the comparing DC voltage, a comparison can be made in the timing before the resonance voltage equivalently becomes zero voltage. |
