| 摘要 |
PURPOSE:To make available a highly precise weight measuring without the need to adding a temperature compensating circuit, by constituting a means detecting a weight of foodstuff by a bridge circuit including a strain sensor and a fixed resistor, and a differential amplifying circuit. CONSTITUTION:A weighing mechanism 5 of a weighing machine is housed in a lower part of outer shell 4 of an electronic cooking range and adapted to detect the weight of foodstuff placed on a receiving tray 9 by converting a resistance linear variation of strain sensors 7-1 and 7-2 pasted on a cantilever type plate 6 into a voltage variation. In this invention, strain sensors 7-1 and 7-2 are respectively connected with fixed resistors 8-1 and 8-2 having the same impedance as that of the former for constituting a resistance bridge. A potential difference between the resistance bridges A and B, which difference getting larger proportionally with a weight of foodstuff placed on the receiving tray 9, is amplifyed by a differential amplifyer 10, then converted by an A/D convertor 11, and then input to a microcomputer 12. Value calculated by the microcomputer 12 is displayed on a displayer (not shown). |
