File name 4440_RTD_Require.pdf
RTD Instrumentation Requirements
By Tom Hayden and Joel Roop
Keithley Instruments, Inc.
Temperature measurement is vital in many processes, during product
development, in safety systems and a host of other applications. For the majority
of these applications, a temperature sensor in contact with a solid surface, or
immersed in a fluid, can be used. The most commonly used contact sensors are
thermistors, thermocouples, and RTDs (resistance temperature detectors).
An RTD frequently is the sensor of choice when sensitivity and application
flexibility are the most important application criteria. They can be manufactured in
a variety of configurations and used for measurements covering a wide
temperature range. When a 100ohms RTD is properly excited (~1mA), it will
produce a 400