Analog Input Channels Temperature is a measure of the average
kinetic energy of the particles in a sample of matter expressed
in units of degrees on a standard scale. You can measure
temperature in many different ways that vary in equipment cost
and accuracy. The most common types of sensors are
thermocouples, RTDs, and thermistors. Figure 1. Thermocouples
are inexpensive and can operate over a wide range of
temperatures. Thermocouples are the most commonly used
temperature sensors because they are relatively inexpensive yet
accurate sensors that can operate over a wide range of
temperatures. A thermocouple is created when two dissimilar
metals touch and the contact point produces a small open-circuit
voltage as a function of temperature. You can use this
thermoelectric voltage, known as Seebeck voltage, to calculate
temperature. For small changes in temperature, the voltage is
approximately linear. You can choose from different types of
thermocouples designated by capital letters that indicate their
composit