Choosing a Temp Sensor – RTD – Thermistor

Plus: Thermistor vs RTD vs Thermocouple

Some basics in this quick little YouTube Video and an intro to NI’s Tutorial on RTDs & Thermistor considerations.

Online — Signal Conditioning Requirements for RTD and Thermistor Sensor output signals are typically in the millivolt range, which means that one must pay careful attention to the sources of error that can impact system measurement accuracy.

The primary signal conditioning factors to consider for resistive sensor measurements are:

  • Noise considerations
  • Connection configuration
  • RTD and Thermistor Excitation.

Because RTDs and thermistors are resistive devices, you must supply them with an excitation current and then read the voltage across their terminals. If extra heat cannot be dissipated, I2R heating caused by the excitation current can raise the temperature of the sensing element above that of the ambient temperature.

Self-heating actually changes the resistance of the RTD or thermistor, causing error in the measurement. Self-heating effects can be minimized by supplying lower excitation current.

This National Instruments (NI) tutorial introduces and explains the concepts and techniques of measuring temperature with a resistance temperature detector (RTD) or thermistor.

Table of Contents

  1. Signal Conditioning Requirements for RTD and Thermistor Sensors
  2. NI-Compatible RTDs Platforms for Measuring
  3. RTDs NI Platforms for Measuring Thermistors
  4. Learn more about Understanding and Choosing RTDs or Understanding and Choosing Thermistors before you begin.

Read the complete tutorial online at: www.ni.com/white-paper/3643/en