By Brian Smith
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22 Sep, 2021
Even though they mostly remain unseen, sensors are necessary for every day, essential systems and devices. Temperature is an important measurement of environmental and physical conditions because it is important for many applications. Measuring temperature might seem unimportant for many, but precise and consistent temperature measurement is essential for electronic systems and devices. To deal with issues associated with heat, engineers and designers have several options at their disposal. On the surface, selecting the best sensors for a device and application can feel overwhelming. Although there are many options, two are ideal for most situations: NTC and RTD. NTC Thermistors – NTC stands for negative temperature coefficient, and they are thermally sensitive resistors. They demonstrate a negative temperature coefficient of resistance, which is done through a decrease in resistance proportionate to temperature increase. This is referred to as a non-linear relationship between temperature and resistance. This is most beneficial in an application that demands accurate temperature measurements. NTC thermistors work within a narrow range of temperatures. RTDs – RTDs stand for resistance temperature detectors, and they are also thermally sensitive resistors (like NTC thermistors). The difference, however, is that an RTD exhibits a positive temperature coefficient, whereas an NTC thermistor does the opposite. An RTD increases the resistance of a device as the temperature increases. An NTC is considered non-linear, and RTD is nearly linear (for a wide range of temperatures). Many engineers find the linear response beneficial when converting resistance readings into clear and accurate temperature values. As a result of this function, RTDs is often the more suitable option for applications with a wide range of operating temperatures.