Specifically, temperature monitoring circuits typically include a temperature sensor and a circuit to measure the resistance of the sensor. This circuit is usually a voltage divider, and the voltage divider can determine the resistance by measuring the voltage difference between the resistors. These measurements can be processed by a computer or microprocessor program and converted to a temperature value.
Simply put, a temperature monitoring circuit determines the temperature value by using a temperature sensor to measure the change in resistance due to a change in temperature.
The temperature monitoring circuit may also use other types of sensors such as thermocouples and thermistors. A thermocouple is a resistor made of two different metals, one of which has a resistance that varies with temperature. A thermistor is a varistor whose resistance varies with temperature. Both thermocouples and thermistors can have their resistance changes measured using a circuit similar to a voltage divider to determine the temperature value.
Also, some temperature monitoring circuits use digital sensors, such as the DS18B20, which can directly convert the temperature value to a digital output that can be used in digital circuit systems.
In summary, temperature monitoring circuits determine temperature values by using various types of sensors, and various types of measurement circuits. It can be used in a variety of applications such as industrial process control, home automation, medical devices, etc.
Another type of temperature monitoring circuit uses self-excited temperature sensors, such as RTDs and NTCs, which undergo nonlinear resistance changes, and these sensors require the use of high-precision circuits to measure and correct the temperature.
Alternatively, an analog or digital interface may be used in the temperature monitoring circuit to convert the signal to a computer or microcontroller readable signal for further processing or storage.
For high-precision applications, calibration and linearization circuits are often required to correct the nonlinear nature of the sensor.
In summary, temperature monitoring circuits can be customized to meet the needs of different applications by using different types of sensors. Temperature values can be determined by using different measurement methods and circuits. Analog or digital signals can be used to transmit the measurements. And, calibration and linearization circuits can be used to improve accuracy.