Method for controlling read-time of a humidity sensor in a microwave oven

A method of controlling read-time of humidity sensor of a microwave oven for cooking food using an oscillation of a magnetron, the method comprising the steps of:

• (a) dividing one period of a frequency of a power source of the microwave oven into a first section and a second section according to an external interrupt signal generated in a zero-crossing point of a frequency signal of the power source, the first section and the second section having the same period;
• (b) sensing humidities repeatedly and respectively in the first section and the second section, and then increasing a noise count in the first section and the second section when a difference between a maximum value and a minimum value in each section is larger than a predetermined reference value;
• and
• (c) comparing noise counts obtained in step (b) with each other, and then determining one of the first and the second sections as a humidity sensing read time section when the count of said one section has less noise count than that of other section.