K type thermocouple amplifier circuit

K type thermocouple amplifier circuit measurement is actually measuring the cold junction at zero for specification, however, usually when measuring instrument is under room temperature, due to the cold end is not zero, forming thermoelectric potential difference decreases, and the measurement error, display an error. The compensation measures is the cold junction compensation.

thermocouple measuring temperature request when its cold end ( Measure the end for the hot end, through lead and the end of the measurement circuit connection is known as the cold end) Stick to the same temperature, the thermoelectric potential size had certain proportion relationship with measuring temperature. When measuring, the cold end ( Environment) Severely affected by the temperature change, the measurement. Take action at the cold end compensation because of the effect of cold end temperature change is called a thermocouple cold junction compensation.

thermocouple cold junction compensation is usually used in the cold end of a bridge composed of thermal resistance in series. The three bridge arm resistance for the specification, in addition, there are a bridge arm by ( Copper) Thermal resistance. When the cold end temperature change ( For lower) , thermocouple thermoelectric potential will change ( Reduce) Series, while the heat resistance of bridge resistance will also change and make the change also appeared at the ends of the bridge voltage ( Reduce) 。 If well parameter selection and wiring is correct, bridge the voltage as it happens and thermoelectric potential change with temperature and the amount of change are equal, all thermocouples at http://www. wuxiyibiao。 Com/measuring circuit of the input voltage ( Potential) Exactly reflect the measured temperature value.