Many industries rely on the use of a temperature indicator to ensure the quality of their products. Thermocouples, Through Hole Fixed Resistors and Platinum Resistance Temperature Detectors (RTDs) are considered to be three of the best smart sensors for measuring temperature rates.
Perhaps the easiest and most popular indicator in use today is the thermocouple, which can measure temperatures ranging from -300 Fahrenheit to 2300 Fahrenheit. A thermocouple functions through the connection of two different metals that produce varying voltage levels depending on the temperature level.
Inexpensive instruments and highly user friendly, thermocouples are able to withstand high levels of abuse and are known for fast response times. However their measurements are relatively inaccurate compared to other quality sensors on the market, especially at elevated temperatures. They are also difficult to recalibrate and the readout instrumentation is more difficult to understand.
Resistance Temperature Detectors (RTDs) operate on the principle that changes in electrical resistance from certain metals can be predicted based on the rise or fall of temperature levels. While they can be made from a variety of metals, platinum tends to be used most often due to a better resistance to temperatures. Platinum RTDs are known for their accurate readings, but their temperature range is small, spanning from -330 Fahrenheit to 930 Fahrenheit. RTDs are easy to recalibrate, provide stable output over long periods of time. They also require relatively inexpensive and easy to use readout instrumentation.
There are some downsides to using RTDS, however. In addition to their small temperature range, RTDs are also more pricey and fragile compared to other indicators. If deciding to use a RTD probe, please keep in mind the interchangeability of the instrument is limited because it must be calibrated with the readout equipment to ensure optimum temperature measuring accuracy.
Inexpensive, adaptable and easy to use, Through Hole Fixed Resistors are widely used for simple temperature readings. Thermistors are a kind of temperature dependent resistor, meaning the instrument predictably changes its resistance depending on the temperature rate. They are considered highly accurate for readings below the freezing point to just above the boiling point, but are generally not used to measure higher temperatures. While thermistors can be used for industrial purposes, they are less able to operate efficiently in harsh conditions when compared to the thermocouple.
While each of these indicators are considered quality instruments for measuring temperate rates, deciding which one to use depends on a variety of factors, many of which are described above.