학술논문
Control device for heating sources of cooking appratus
Document Type
Patent
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Abstract
Control device for the heating sources of a cooking apparatus, in particular of a cooking surface, possessing a set of neighboring heating sources and a smooth sheet of vitroceramic glass, of uniform thickness, inparticular covering the entire surface, having a plurality of sensitive keys actuated by the approach of a user's finger into contact or into immediate proximity with the surface of the sheet.
According to the invention, each key is associated with a specific source and is formed by the two metal armatures, disposed substantially in the same plane, of a single capacitor carried by a printed circuit board attached under the sheet opposite the upper surface thereof, the capacitor having its first armature connected to a pulse generator and its second armature connected to a differential comparator, the first, peripheral armature having a general U-shaped profile which surrounds the second, central armature in a manner such that the approach of the finger directly over the capacitor but on the other side of the sheet, towards or against its upper surface, modifies its capacitance and causes a change of state at the output of the differential comparator capable of varying the electrical voltage supplied to the source associated with the key.
According to the invention, each key is associated with a specific source and is formed by the two metal armatures, disposed substantially in the same plane, of a single capacitor carried by a printed circuit board attached under the sheet opposite the upper surface thereof, the capacitor having its first armature connected to a pulse generator and its second armature connected to a differential comparator, the first, peripheral armature having a general U-shaped profile which surrounds the second, central armature in a manner such that the approach of the finger directly over the capacitor but on the other side of the sheet, towards or against its upper surface, modifies its capacitance and causes a change of state at the output of the differential comparator capable of varying the electrical voltage supplied to the source associated with the key.