工作电流对热敏电阻测温的影响

热敏电阻是一种在航天领域广泛应用的测温元件,由于其一致性差,使用时必须给出每个元件的电阻-温度对应关系.在标定时,通过控制测量电流来防止热敏电阻发热.而在实际使用中,通过热敏电阻的电流很难控制,电流往往过大,引起热敏电阻发热,给测量带来误差.其误差取决于热敏电阻上消耗的功率.因此,选取温度上升值与热敏电阻上消耗的功率之比为修正系数,采用理论计算来对热敏电阻因电流增加所带来的测量误差进行修正.实践证明,修正系数在不同的温度与电流下基本不变.根据热敏电阻的型号和实际被测对象,测量出修正系数,用理论计算修正后将大幅减少电流引起的误差,保证测量的准确性.

The thermometric error of thermal resistor effected by working current

Thermal resistor, a kind of thermometric element, is extensive used in the field of astronautics. Because of bad concordance, the corresponding relationship between the resistor and temperature must be calculated when the element is used. In order to prevent generating heat, the measurement current is controlled when calibrating. But it is difficult to control the thermal resistor current in actual use. The heating of thermal resistor caused by large current bring the error which depend on consumption power into measurement. So, the ratio between the temperature rising data and the consumption power is selected as correction ratio. The measurement error caused by current increasing is corrected by theoretical calculation. Certified by experience, the correction ratio is a invariable data in different temperature and current. For the accuracy of measurement, the error caused by current iscorrectbytheoreticalcalculationaccordingtothethermalresistortypeandactualobject.