Thermistors

Providing accurate and sensitive measurement and control of temperatures, choose RS' extensive catalog of durable thermistors and build efficient temperature-controlled circuits.

All thermistors for sale in our range are crafted from the highest quality materials by well-known thermistor suppliers such as Vishay Dale, Honeywell, and Amphenol Advanced Sensors. Our stock includes countless types, such as current-limiting, high sensitivity, harsh environment, and hermetically sealed thermistors too, so whatever your project or application, we can help.

We stock many different types of thermistors, so use the search features to restrict your search for components by feature, manufacturer, type, and more. If you would like more information on temperature thermistors, their function, and use, then scroll down. Want to know more? Get in touch or explore our expert hub to have all your questions answered.

What is a thermistor?

Thermally sensitive resistors, thermistors are components that, upon sensing a shift in temperature, resist the current flowing through them proportional to the temperature change.

They are typically used to measure temperature changes. As the temperature around the thermistor changes, the semiconducting materials within them alter the voltage running through the component. This is read by a temperature controller, with the data generated used to inform the function of other components within the circuit.

How do different thermistor temperature sensors work?

Thermistor temperature sensors work according to the materials used in their construction - these change the scaling of the resistance proportional to temperature change. Every thermistor is made from semiconducting metallic oxides pressed into shape (a bead, cylinder, or disk, for example), which is coated with a watertight material, commonly glass or epoxy.

As these oxides are heated, their electrical resistance either increases or decreases. This depends on the different types of thermistor they are used in, of which there are two:

NTC thermistors - Negative temperature coefficient (NTC) thermistors decrease their electrical resistance as the sensed temperature increases and vice versa. They are often used to measure temperature, whether in heating systems, automotive temperature sensors, or to limit currents within power supply circuits to safe levels.

PTC thermistors - The resistance of positive temperature coefficient (PTC) thermistors increases as temperature increases. They are often used within self-regulating heaters - as temperature drops, more current is applied to the heating element, increasing the ambient temperature. They can also protect against over-currents, acting as a resettable fuse that stops the current until the thermistor body temperature drops to a safe level.

What is the difference between a thermistor and a resistance temperature detector (RTD)?

While they are similar temperature probe devices, there are some key differences between thermistors and RTDs that inform their proper usage.

Thermistor temperature sensors are less expensive, more durable, typically provide a more accurate range of temperature measurement, and can much more rapidly change their resistance in line with temperature fluctuations, than RTDs.

However, their temperature measurement ranges are much lower than RTDs, and the correlation of their resistance to temperature change is non-linear. Resolving this can be complex yet must be accounted for to accurately read the thermistor data. Thermistor components can also generate heat, which can lead to false readings.

RTDs, on the other hand, are made from metal, which means they can cope with much higher temperate ranges than thermistors, and their resistance to temperature correlation is linear. They are larger and more expensive, however, and are less sensitive, changing resistance by fewer ohms per degree than thermistors.

What the applications of thermistors?

Used across many industrial, manufacturing, or electronic application where gas, liquid, or surface temperatures must be measured or responded to, thermistor temperature sensors are extremely common components.

They are used in food manufacturing, where temperatures must be controlled to moderate the condition of the food or sanitary environment. In chemical and petrochemical production, non-corrosive thermistors play a great part in producing various fluids, and safely. In aerospace, communications, electronics, and medicine, they benefit both the precise manufacture of equipment and bring temperature-sensing capabilities to the products themselves.

And in everyday life, they ensure that ovens, heating systems, air conditioners, and fire alarms can function correctly, and temperatures within vehicle engines can be controlled.

Why trust RS as your thermistor distributor?

By purchasing thermistors from RS, you benefit from nearly a century of expertise in electrical component distribution.

We are one of the largest authorized distributors in North America and have close partnerships with a vast range of component suppliers like Omron Automation, EPCOS, AVX, and Sensata. That means we are almost certain to have the thermistor you need for the task at hand.

Search our range by resistance - view NTC thermistors, PTC thermistors, or ICL and PPTC components - and browse by tolerance, termination type, and much more. Simply use the menu on the left to narrow your selection.

If we don't have the temperature thermistors you need, please don't hesitate to get in contact with our specialists and they'll be happy to help. Explore our expert hub to learn more.