A Basic Guide to RTD Measurements
RTDs, or resistance temperature detectors, are sensors used to measure temperature. These sensors are
the among the most accurate temperature sensors available, covering large temperature ranges.
However, getting accurate measurements with precision analog-to-digital converters (ADCs) requires
attention to detail in design of measurement circuits and calculation of the measurement. This application
note starts with an overview of the RTD, discussing their specifications, construction, and details in their
use in temperature measurement. Different circuit topologies with precision ADCs are presented for
different RTD configurations. Each circuit is shown with a basic design guide, showing calculations
necessary to determine the ADC settings, limit measurement errors, and verify that the design fits in the
operating range of the ADC.