METHOD OF REDUCING MEASUREMENT ERROR OF TEMPERATURE WITH ELECTRIC BRIDGE AND MEASURING AXLE OF WHEATSTONE-KAPINOS Russian patent published in 2020 - IPC G01K1/20 G01R17/10 

FIELD: measurement.

SUBSTANCE: invention relates to measurement equipment, in particular to measurements of electrical resistances by electric bridges, and can be used in temperature measurements, including during calibration of thermoresistors: resistance thermometers, thermistors, posistors and their use when measuring temperature by electric bridges, as well as in instrumentation for construction of measuring bridge converters. Essence of the disclosed solution lies in the fact that in the method of temperature measurement based on the use of an electric bridge with a thermistor, determining by design the permissible current value in the measuring branch of the bridge, caused by the permissible error of temperature measurement by the thermistor due to its heating by the flowing current, setting and during measurement of temperature maintaining permissible value of current in measuring branch of bridge, and permissible value of current flowing in measuring branch of bridge is determined according to expression:

where ΔT^Perm permissible error of temperature measurement by thermistor due to its heating with flowing measurement current; δ_T is thermoresistor thermal dissipation coefficient;

is maximum resistance of thermistor at boundaries of measured temperature range: for thermistor - lower limit of measured temperature range; for resistance thermometer and posistor - upper limit of measured temperature range. Besides, the invention proposes a measuring bridge for temperature measurement, consisting of three resistors and a thermistor, connected in series in form of a quadrangle, a potential difference meter included in the bridge load diagonal, and a power supply included in the diagonal of supply of the bridge, in which: power supply source used is a controlled power supply, control inputs of which are connected to outputs of constant resistor, which is included in measuring branch of bridge, containing thermistor.

EFFECT: reduced error of temperature measurement due to reduction of heating (self-heating) of thermistor (resistance thermometer, thermistor, posistor) with flowing measurement current and providing linearity of electric bridge conversion function.

5 cl, 6 dwg