METHOD OF REDUCING MEASUREMENT ERROR OF TEMPERATURE WITH ELECTRIC BRIDGE Russian patent published in 2019 - IPC G01R17/10 G01K7/08 

FIELD: measuring equipment.

SUBSTANCE: invention relates to measurement equipment, in particular to measurements of electric resistances by electric bridges, and can be used, for example, in temperature measurements, including at calibration of resistance thermometers, thermistors and posistors, at temperature measurements with electric bridges. Essence of the disclosed technical solution lies in the fact that in the method of reducing temperature measurement error by an electric bridge, supplied from a voltage source, in the measuring branch of the bridge there installed is a constant resistor with high electric resistance, and the value of voltage of the power supply source of the bridge is selected from the condition of provision of permissible error of temperature measurement by the bridge due to heating of thermistor by flowing measuring current. Besides, in the proposed method to achieve the set goal: thermistor can be used as thermal resistor, resistance value of constant resistor in measuring branch of bridge is selected not less than 0.8 of value of resistance of thermistor at lower boundary of range of measured temperatures, and voltage value of power supply of bridge, providing permissible error of temperature measurement by bridge due to heating of thermistor by flowing measurement current, is set for lower boundary of range of measured temperatures; as a thermistor there can be used a resistance thermometer or a posistor, value of resistance of constant resistor in measuring branch of bridge is selected not less than 0.8 of value of resistance of resistance thermometer or posistor at upper boundary of range of measured temperatures, and voltage value of power supply of bridge, providing permissible error of temperature measurement by bridge due to heating of resistance thermistor or posistor with flowing measurement current, is set for upper boundary of range of measured temperatures; value of power supply voltage of bridge, providing permissible error of temperature measurement by bridge due to heating of thermistor, can be installed using expression

where R₄ is the value of the resistance of the corresponding thermistor in the measuring branch of the bridge at the corresponding boundary of the range of measured temperatures; R₃ is resistance value of constant resistor in measuring branch of bridge; ΔT is permissible error of temperature measurement by the bridge due to heating of thermistor by flowing measurement current; δ_T is coefficient of thermal dissipation of appropriate thermistor.

EFFECT: reduced error of temperature measurement by electric bridge due to heating (self-heating) of thermistor (resistance thermometer, thermistor, posistor) flowing measurement current.

3 cl, 6 dwg, 1 tbl