After time, temperature is the variable most frequently measured. The three most common types of contact electronic temperature sensors in use today are thermocouples, resistance temperature detectors (RTDs), and thermistors. This article will examine the negative temperature coefficient (NTC) thermistor.

Photo 1. NTC thermistors are manufactured in a variety of sizes and configurations. The chips in the center of the photo can be used as surface mount devices or attached to different types of insulated or uninsulated wire leads. The thermistor element is usually coated with a phenolic or epoxy material that provides protection from environmental conditions. For applications requiring sensing tip dimensions with part-to-part uniformity and/or smaller size, the devices can be encapsulated in PVC cups or polyimide tubes.