Krets för att noggrant mäta belastningen av tillagningsmat i mikrovågsugn

摘要

The invention discloses a circuit for precisely measuring the weight of the cooking food in a microwave oven. The circuit is capable of reducing the variation of the weight-voltage converted value due to the existence of the tray during the measurement of the weight of the cooking stuff. The circuit includes: a piezo-electric sensor for generating a sinusoidal wave each time each of rollers passes the pressing plate of said sensor; a filtering section for shaping the weight-voltage converted sinusoidal wave of said piezo-electric sensor; an amplifying section for amplifying the weight-voltage converted sinusoidal wave output of said filtering section to above the maximum recognizable voltage Vmax of a microprocessor; a rectifying section for charging or discharging the weight-voltage converted sinusoidal wave output of said amplifying section; and a buffer section for supplying to said microprocessor the weight-voltage converted output having a corrected gradient as a result of adding an adder voltage (-V1) as much as the minimum recognizable voltage Vmin of said microprocessor to the weight-voltage converted gradient of said rectifying section.