What is a Thermometry Bridge?
We continue our Introductory Guides to Temperate Metrology and are looking at thermometry bridges. We look at why many calibration laboratories use “bridges” rather than DVMs or Bench Thermometers, how these bridges are used and then we introduce the Isotech microK range of bridges.
What is a thermometry bridge?
A thermometry bridge is the best way to measure the resistance of a Standard Platinum Resistance Thermometer.
Why make ratio measurements with a bridge?
Measuring ratio has advantages and better performance than can be achieved with a DVM or Precision Thermometer that measure the voltage developed across the resistance thermometer for a known current
What accuracy can be achieved with a bridge?
At best accuracies can be in the order 20 µK, 20 millionths of a degree! At this level temperature-controlled Standard Resistors are used.