LTC2053 thermocouple amplification circuit diagram

The amplifier LTC2053 amplifies the output mv model of the thermocouple. Since the LTC2053 works on the sampled input signal, the frequency of interest is generally lower than a few hundred Hz. In this way, adding a 0.1 fog capacitor C1 in the feedback circuit can speed up the response of the amplifier. . Capacitors C2 and C3 connected to the thermocouple input network help absorb radio frequency interference and suppress interference in the thermocouple probe.

Sampling interference occurs. Resistors R6~R9 connected in the thermocouple provide high impedance bias, which maximizes the interference immunity of the probe without voltage drop. Short thermocouples minimize common-mode signals and allow the probe node to be grounded. The 5.1V voltage regulator tube VD1 forms a power supply protection circuit, which prevents overvoltage of the power supply and reverse polarity of the 6V battery. R3 is a current limiting resistor. The working principle of a thermocouple is to generate a potential difference based on the temperature difference between the hot end and the cold end. Since the temperature of the cold end is often not 0°C during actual measurement, the thermocouple needs to be temperature compensated.