| 摘要 |
<p>A fluorescent display tube power supply device in a microwave oven comprises circuitry for generating a stable voltage supply for a microcomputer by rectifying the output of a first secondary coil of an AC power transformer, and rectifying a half wave of the output from a second secondary coil of the transformer, one-half cycle of which is applied to a heater of the fluorescent display tube. A rectifying circuit generates a double voltage from the output of the second secondary coil, the double voltage being mixed, in direction in which it becomes lower than the stable voltage of the microcomputer, thus providing a display erase potential. As a result, the luminance of the display can be maintained constantly unaffected without causing the voltage of the display tube to vary throughout ON-OFF operations of the heating power source, thus achieving a highly satisfactory display effect.</p> |
