Abstract: An electronic control timer of microwave oven capable of establishing a total cooking period by different time units is disclosed. The electronic control timer includes a gear having a first gear segment and a second gear segment. A switch installed adjacently to the gear generates a pulse signal in accordance with a rotation displacement of the gear. The gear driving device is activated when the switch is activated, and then rotates the gear in an opposite direction to an initial rotating directioon of the gear and returns the gear to an initial state thereof. The first gear segment includes a first gear teeth having a first gear pitch corresponding to a first time unit and a second gear teeth having a second gear pitch corresponding to a second time unit. The second gear segment has a toothless shape. The switch is activated when it is brought into contact with the first gear segment so that the switch generates the pulse signal.

Abstract: A power supply converting circuit for eliminating abnormal voltage components, such as an electrical noise component and a surge component, from the commercial alternating current without a transformer and for converting the commercial alternating current into a weak direct current and/or an alternating current having a low voltage to apply the weak direct current and/or the alternating current having a low voltage to a load. A filter filters the commercial alternating current and is connected to main power transmission live lines of the commercial alternating current power. A power level adjusting section receives the filtered alternating current in the filter to convert a power level of the received alternating current. A snubber circuit receives the power level converted alternating current in the power level adjusting section and eliminates the abnormal voltage components of the power level-converted alternating current.