二进制数控电桥测室温

摘要

传统惠斯登电桥受限于电阻箱的测量精度，往往无法准确测量温度。根据二进制数控R-2R电阻网络的伏安特性，把R-2R电阻网络作为惠斯登电桥的比例臂，通过12个手动开关(或者360度旋转编码器)调节比例臂电阻的比值以实现电桥的平衡。并通过运算放大器调节检流计灵敏度以测量PT100的阻值，从而实现对室内温度的精确测量。%It is difficult to measure the precision indoor temperature with traditional Wheatstone bridge limited by measurement precision of the resistance box. According to the volt ampere characteristic of the Binary Digital R-2R resistor network,the balance of the bridge is realized by 12 manual switch( or 360 degree rotary encoder) to change the arm resistance which is the R-2R resistor network. The resistance of the PT100 is meas-ured by the operational amplifier which raised the galvanometer sensitivity,so the accurate measurement of the indoor temperature is achieved.