How Do Thermal Resistors Work?
A thermal resistor is a special type of resistor that is sensitive to temperature, more so than other normal resistors. The term is a blend of thermal and resistive resistor. The thermal resistor has two physical structures, a thin metallic film or a metallic plate, which is electrically insulated from the rest of the circuit. These two structures are connected to a core through a pair of conducting connections. The thermal parts melt when the temperature rises, thus rendering the portion that contains the resistive material non-resonant and therefore less sensitive to temperature changes.
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How Do Thermal Resistors Work?
A thermal resistor is a special type of resistor that is sensitive to temperature, more so than other normal resistors. The term is a blend of thermal and resistive resistor. The thermal resistor has two physical structures, a thin metallic film or a metallic plate, which is electrically insulated from the rest of the circuit. These two structures are connected to a core through a pair of conducting connections. The thermal parts melt when the temperature rises, thus rendering the portion that contains the resistive material non-resonant and therefore less sensitive to temperature changes.
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In electrical engineering, a thermal resistor is defined as any device that exhibits a linear current when its temperature increases beyond a threshold value, which is set by the manufacturer. In a thermal receiver, the thermal resistor acts as an output control variable. In an electronic circuit, the thermal resistor permits current to be controlled by altering the voltage across the circuit. Thus, in both electronics and circuits, the thermal resistor allows a method of temperature control. This can be seen by the equation of thermal conductance and thermal Resistance, which relate the thermal resistance with the temperature.
When a current is forced through a thermal resistor, its resistance changes depending on the temperature increase and the value of the thermal resistor is determined by the thermal conductivity of the metals being used in the circuit. Thus, it can be said that the resistance changes as a result of the current and not as a result of the temperature increase. This is the reason why most resistors have a built-in safety feature wherein the current can be controlled automatically at high temperatures. However, such a feature is only available in conductors with low-molecular weight; conductors with high thermal conductivity can be used without such safety feature.
There are several classes of thermally sensitive resistors and each has its own advantages and disadvantages. There are also several classifications of thermally sensitive device. These may include piezoelectric, thermal, photovoltaic, piezoelectric, and some other types. The different classes of thermally sensitive devices are separated based on the temperature sensitivity of their semiconductor diodes. The thermal tolerance of the device is measured by its minimum temperature ability to withstand a certain temperature rise of the semiconductor material. This maximum temperature is what is termed as the threshold temperature.
The threshold temperature is measured as the percentage change in the resistance’s value when the current is applied at the lowest possible level. A thermal resistor will have a high threshold temperature if the resistance does not respond to a changing input voltage at all. In such a situation, the thermal resistor will fail to measure temperature changes. A positive thermal coefficient will reduce this failure rate because the output current will only reach a predetermined maximum before it starts decreasing. A negative thermal resistor will only reach the predetermined maximum until the input current has reached its maximum.
There are also thermocouple based monitor which uses electromagnetic impulses for the measurement of temperature changes. One example is the thermal resistor that is based on the electromagnetic induction technique. The other example is the infrared thermocouple that works through shining infrared laser light on metals to determine their temperature. Both of these thermocouples are used for different applications, but they are basically the same concept.