Development of a Temperature-Controlled Resistance Micro-Change Experimental Device

In order to solve the problems of small change of resistances, which is difficult to control, a design of experimental device based on temperature-control and micro-change of resistance is introduced. Ohm's Law and Direct Current Potential Drop method (DCPD) has been used.AT89S52 MCU was applied to the micro controller. The precision amplifying circuit based on an operational amplifier AD620 and OP07ADJ with high precision, low drift and low bias voltage, through data acquisition, Analogue to Digital (A/D) conversion, the data are processed and displayed by MCU, and the principle of small change of the resistances and the feasibility of the measurement are analyzed. The experiments show that the micro-change of resistance is accurate measured under the micro-change of temperature. The measuring accuracy reaches 1/100 when the environment temperature is 20~65°C, and the resistance value is 0.13~0.16Ω.