Thermocouples produce a measurable voltage as the surrounding temperature increases or decreases, where thermistors change their resistance to electrical current as the temperature changes. Also, thermocouples and thermistors are used in different applications, depending upon the precision needed and the temperature ranges involved.Know More
Thermocouples exploit the fact that when two dissimilar metals are joined together and in the presence of changing temperatures, a difference in the electrical potential, or voltage, between the two metals changes. This is known as the Seebeck Effect, named after its discoverer, Thomas Seebeck. Thermocouples are used in high-heat applications, typically where they are the only viable option. However, when compared to thermistors, thermocouples are not as precise or accurate and often need recalibration before and after each use.
Thermistors, on the other hand, are restricted to lower-temperature applications but have much better accuracy and reliably track changes far more precisely than the average thermocouple. Because they are small, lightweight and very accurate, thermistors are more often used in conjunction with microprocessors and data recording units. Thanks to their smaller sizes, thermistors are often arranged with redundant counterparts for data integrity. Since they produce such large, proportional changes in resistance for a given change in temperature, thermistors provide a much more accurate representation of the actual changes in temperature.Learn more about Measurements
Digital thermometers work on the principle that changes in temperature cause the resistance of a sensor to change allowing a computer to convert the difference to a digital read-out. The sensor is a thermoresistor, commonly called a thermistor, according to HowStuffWorks.com.Full Answer >
While the majority of thermometer manufacturers no longer make mercury thermometers as of March 2015, a few manufacturers still produce them for industrial or laboratory use. Many states, including California, Massachusetts and Washington, have passed laws to limit the manufacture or sale of mercury thermometers.Full Answer >
The difference, or subtraction, between120 hertz and 240 hertz is 120 hertz. These two frequencies are typically used to measure the refresh rate of high-definition televisions. Although in theory a higher refresh rate frequency is better, in actuality it makes little difference, explains PC Magazine.Full Answer >
The main difference between 120V and 240V is the amount of electrical power that flows through the wires. Outlets with a 240V rating supply twice as much electrical power as those rated 120V.Full Answer >