| 摘要 |
PURPOSE: A power control device of a microwave oven is provided to reduce production cost by substituting an inrush coil and a relay coil with another inexpensive components. CONSTITUTION: Upon closing a door, a main contact point(31) of a monitor switch is connected to a transformer contact point(33). First and second door switches(3,5) are turned on and currents from a power supply unit(1) flow along first and second normal AC power lines(2,4). The current flowing along the first normal AC power line is supplied to a switching thermistor (25) and a high voltage transformer(9) while the current flowing along the second normal AC power line is supplied to an inrush thermistor(23). While an inrush TCO(21) is turned off, the initial inrush current supplied to the inrush thermistor is offset by the inrush thermistor. If the resistance of the switching thermistor is increased by the current supplied to the switching thermistor, heat is generated and the inrush TCO is turned on. Then, the offset initial inrush current is supplied to the high voltage transformer via the inrush TCO. The switching thermistor continuously generates heat by the current supplied to the switching thermistor, and the inrush TCO is kept in the turn-on state. By using the static thermistor and TCO instead of an inrush coil and an inrush relay, production cost is reduced.
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