| 摘要 |
PURPOSE:To obtain an inexpensive weigher having simple circuit constitution by making rates of a positive voltage and a negative voltage slightly different from each other to apply them to a weighing sensor as power not to give both of positive and negative polarities to an output voltage. CONSTITUTION:In consideration of influences of variance of temperature, wind, etc., voltage rates of positive and negative voltage sources 2 and 3 whose voltages are applied to a weighing sensor 1 are slightly unbalanced preliminarily so that an output voltage V1 of a differential amplifier 4 is not negative. In this case, the output voltage V1 is biased, and an output corresponding to unbalance is generated even if the load is 0g. A value corresponding to unbalance is set to a preset circuit 16 preliminarily, and this value is subtracted from the output value of a counter 8 by a subtracting circuit 17 to obtain a correct weight value, and this value is displayed. Thus, the circuit constitution is simplified to obtain an inexpensive and high-precision weigher.
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