| 摘要 |
PROBLEM TO BE SOLVED: To provide the measuring instrument which is low-cost and has high measurement precision as a temperature measuring instrument which uses a three-wire temperature measuring resistance body. SOLUTION: Reference resistance bodies 31, 32, 33, and 34 are prepared and in addition to wires 3a and 3b of a temperature measuring resistance body sensor 1, those reference resistance bodies are connected to a constant-current power source 14 in order; and generated voltages are measured and compared to find the temperature. The temperature measurement can be performed by the one constant-current source, and the draft, etc., of the constnat-current source can be canceled by comparing the voltages developed at the reference resistance bodies. The elements other than the resistance bodies need not be high in precision and stability so much, so the temperature measuring instrument 10 having high precision can be provided by using an inexpensive circuit.
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