Resistance to temperature conversion table

They can be encapsulated in epoxy resin, glass, baked-on phenolic, or painted. Thermistors come in a variety of shapes-disk, chip, bead, or rod, and can be surface mounted or embedded in a system. Sensitivity: The degree of response to a change in temperature. Stability: The ability of a controller to maintain a constant temperature based on the sensorвЂ™s temperature feedback. This is the time, in seconds, that a thermistor takes to reach 63.2% of the temperature difference from the initial reading to the final one. Time Constant: Approximate time required to change from one temperature value to another.

For example, thermistors are inexpensive in relation to RTDs, partly because the material of choice for RTDs is platinum. Relative Cost: Relative cost as these sensors are compared to one another. Within a given temperature range, some sensors work better than others. Temperature Range: The approximate overall range of temperatures in which a sensor type can be used. The table below gives a brief comparison of the benefits and drawbacks of each. Which sensor works best for a particular use is based on many factors. The most common are Resistance Temperature Detectors (RTD) and integrated circuits (IC), such as the LM335 and AD590 types. In addition to thermistors, several other types of temperature sensors are used. What is the difference between a thermistor and other sensors? How the change in resistance is converted into measurable data will be covered in detail below. A typical thermistor graph looks like this: The location of the line and how much it changes is determined by the construction of the thermistor. Unlike other sensors, thermistors are nonlinear, meaning the points on a graph representing the relationship between resistance and temperature will not form a straight line. How much the resistance changes depends on the type of material used in the thermistor. How does the thermistor вЂњreadвЂќ temperature?ДЄ thermistor does not actually вЂњreadвЂќ anything, instead the resistance of a thermistor changes with temperature. For example, a 10 kО© thermistor is the standard that is built into laser packages. For more sophisticated applications, such as laser stabilization detectors, optical blocks, and charge coupled devices, the thermistor is built in. Some of the most common uses of thermistors are in digital thermometers, in cars to measure oil and coolant temperatures, and in household appliances such as ovens and refrigerators, but they are also found in almost any application that requires heating or cooling protection circuits for safe operation. They are ideal when very precise temperatures are required. While they do not work well with excessively hot or cold temperatures, they are the sensor of choice for applications that measure temperature at a desired base point. Thermistors are easy to use, inexpensive, sturdy, and respond predictably to changes in temperature. The direction of the arrow or bar is not significant. The arrow by the T signifies that the resistance is variable based on temperature. This range is dependent on the base resistance.ДЇigure 1: Thermistor Symbol - US and Japan Typically, a thermistor achieves high precision within a limited temperature range of about 50вњ¬ around the target temperature. This type of thermistor is generally used as a fuse. When temperature increases, the resistance increases, and when temperature decreases, resistance decreases. This type of thermistor is used the most.ДЄ PTC thermistor works a little differently. Conversely, when temperature decreases, resistance increases. With an NTC thermistor, when the temperature increases, resistance decreases. There are two types of thermistors: Negative Temperature Coefficient (NTC) and Positive Temperature Coefficient (PTC). It is made of metallic oxides, pressed into a bead, disk, or cylindrical shape and then encapsulated with an impermeable material such as epoxy or glass. The term is a combination of вЂњthermalвЂќ and вЂњresistorвЂќ.

A thermistor is a resistance thermometer, or a resistor whose resistance is dependent on temperature.

Resistance to temperature conversion table