主要论述了金属材料膨胀尺寸的测量。测量方法采用了差动式电容型膨胀尺寸传感器 ,用此传感器研制成的膨胀尺寸测试仪具有线路简单、成本低的特点 ,输入输出是线性特性 ;且具有较高的抗共模干扰能力 (如温度影响 )。同时给出提高测量精度和灵敏度的措施 Mainly discusses the measurement of metal material expansion size. The measurement method uses a differential capacitance type expansion size sensor. The expansion size tester developed by the sensor has the characteristics of simple circuit and low cost, and the input and the output are linear characteristics; and has high anti-common-mode interference ability Temperature effect). At the same time give measures to improve the measurement accuracy and sensitivity