A basic guide to thermocouple measurements
Thermocouples are common temperature sensors used in a wide variety of commercial and industrial applications. While slightly less accurate than resistance temperature detectors (RTDs), thermocouples cover a wide temperature range, are self-powered, and have a fast response time. Their simple construction make them inexpensive and durable.
Because of the small sensor voltage and low noise requirements, delta-sigma analog-to-digital converters (ADCs) are well suited data converters for measuring thermocouples. This application report from Texas Instruments gives an overview of thermocouples, discussing theory of operation, functionality, and methods in temperature measurement.
Many circuits are presented showing thermocouple connections to precision ADCs. Different topologies focus on biasing thermocouples for the ADC input and for burn-out measurements.
To read the full report, click here.