03.06.2015 Views

Understanding Infrared Thermography Reading 3

Understanding Infrared Thermography Reading 3

Understanding Infrared Thermography Reading 3

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

■ Resistance Thermometers<br />

Resistance temperature detector (RTDs) arc contact sensors thaI measure<br />

tcmpcralUrc by a predictable change in resistance as a function of<br />

temperature. Platinum is the most popular resistance temperature detector<br />

material because of its excellent stability and its linear response to<br />

temperature change. Other materials used include nickel. copper. tungsten<br />

and iridium. In operation. the resistance temperature detector may be placed<br />

in a bridge circuit such that the bridge output voltage is a measure of the<br />

resistance and hence the temperature at the resistance temperature detector.<br />

A more accurate measurement may be achieved by using a constant current<br />

source and a digital volt meter (DVM). such that the digital volt meter reading<br />

is proportional to the resistance temperature detector resistance and hence<br />

the temperature at the resistance temperature detector.<br />

Charlie Chong/ Fion Zhang

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!