A Platinum Resistance Bridge Thermometer
Ximin Liu · 2016
A platinum resistance bridge thermometer is introduced.It implements linear temperature measurement in -200~850 degrees with a bridge circuit.It consists of bridge circuit, multi-channel switches, amplifier, AD574, display, COM port, precision power supply, 89C51 etc.After the analysis of bridge circuit characteristic, a method is presented that the platinum resistance value is obtained by computing the current ratio of tow bridge circuit loop and then looking into the Pt100 reference table to obtain the measured temperature.So the linear temperature measurement is implemented without nonlinear compensation.The measurement error is less than 1.5 degrees.