Resistance Temperature Detectors

Resistance Temperature Detectors

Resistance temperature detectors, or RTDs, are also known as resistance thermometers. RTDs display changes in resistance as temperature changes. Usually made of alloys such as nickel, copper, nickel-iron, or platinum, RTDs are gradually replacing thermocouples for many applications. In general, RTDs offer high stability, repeatability, and accuracy.

The two main types of RTDs are film and wire-wound. Film thermometers, which contain a layer of platinum, work quickly and are inexpensive. Wire-wound thermometers are favorable when the temperatures used vary greatly.

Because of the material's unique characteristics, RTDs are usually made with platinum. Some advantages of platinum RTDs are high accuracy, wide operating range, and low drift.