In general in a microwave oven provided with a microprocessor controlling the operation of the microwave generator or magnetron, the food treatment (thawing, thawing plus heating, or thawing plus cooking) can be preplanned by the user by setting the food weight, the food type and the required type of treatment. These data enable the microprocessor to control the magnetron operation for the time required to obtain the desired treatment.
In known microwave ovens the food weight is determined for example by placing the food on a support to which a weight measurement device or more simply balance is connected. The balance thus enables the food weight to be automatically fed to the microprocessor by merely placing the food in the oven. Such a system is such used. It has however many drawbacks including the high cost of the components and the fact that the weighing device is a very sensitive and delicate mechanism which means that it can be easily damaged during the insertion of the food into the oven and its withdrawal therefrom.