Thermistors: An Overview


A thermistor is a tiny little temperature sensor that uses complicated math formulas to generate accurate temperature readings for various industrial uses. The thermistor is used for temperature sensors, inrush current limiters, overcurrent protectors, and self-regulating heating elements.

The thermistor works because it contains particles that react to changes in temperature. When the temperature changes, the particles expand and place resistance pressure on one another. The device then sends out a signal of the pressure change, which can be converted and displayed as the highly accurate change in temperature. Often, these regulators are used in current-limited devices for current protection instead of fuses. The small design of the resistors makes this usage idea. The temperature regulators are also used to monitor automotive equipment, such as cooling and oil temperature inside the engine. Surprisingly enough, the sensors are also used in many modern digital thermometers for accurate temperature readings in the body. Many appliances, both industrial and residential, use the sensors to regulate the temperature inside the appliance. The food and beverage industry particularly uses a wide variety of thermistor sensors to prevent food contamination.

Although thermistors are similar to resistance temperature detectors, the material used to make the sensor is different. A thermistor is manufactured from ceramic or polymer, while RTDs are made from metal. This makes the thermistor have a different response to temperature change. RTDs provide accurate readings for a high range of temperature, while thermistors are designed to measure highly accurate temperature readings in limited temperature ratings, often between -90 and 130 Celsius.

Even though the thermistor was first discovered and used in 1833, the true potential of the device was not realized until the industrial revolution in the early 1900s. In fact, it was not until 1930 that the thermistor design of today was invented.