Free Simple Circuit Diagram
The figure below shows the schematic of a Digital Thermostat. The output of LM35 is digitized by the A/D. The LM35 is a temperature transducer IC with an output of 10 mV per ‘C. This 10 mV corresponds to 1/2 LSB and the circuit resolution is 2 ‘C if the Vref/2 is set for 2.56 V. The resolution become 1’C […]
Read moreCold junction compensation in thermocouple is needed when the cold junction is not kept on a constant temperature. Rather that to provide temperature stabilizer on the junction, correcting the error by measuring the cold junction temperature is cheaper. Here is one of the circuits for such solution: We can follow these steps to adjust the circuit: Adjust R1 for the […]
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Cold junction error in thermocouple can be seen as an offset drift that depend on the cold junction temperature. we can use the following circuit to correct this error for grounded thermocouple configuration: Adjustments: compensates for both sensor and resistor tolerances Short 1N4568 Adjust R1 for SEEBECK coefficient times the ambient temperature (in K degrees) across R3. Short LM135 and […]
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Differential temperature sensor is used to measure temperature difference in two different area. Here is the schematic diagram of the circuit: Please note that the connection from pin 2 to pin 3 of LM308 shouldn’t be there, just break the connection so we get valid configuration like as we see in other differential amplifier. [Source: STMicroelectronics Application Note]
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