抄録
When the Manganin wire is used in wide temperature scope, its quality should be considered as the function of not only the primary temperature coefficient of resistivity α20 but the secondary temperature coefficient β20 and temperature scope to be used. The author, defining the thermal variation of resistance w (%) to represent the quality of Manganin wire, has shown some experimental way to derive it smoothly. To do this, he divided the temperature range into four stages of each temperature of which the resistance value becomes maximum. Then he derived for each stage such equations as Eqs. (10)-(13) in this paper. These equations are useful to show the possible value of α0 and β0 in order to derive the desired thermal variation (Fig. 2). On a resistance element, the following equation can be easily obtained from several measuring points:
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When every plot of this equation falls inside an encircled zone of Fig. 5, the thermal variation of this element must be within desired value.
