Thermistors

Termistor - what is it?

A thermistor is a type of resistor made of materials that make the resistance value of a component dependent on the temperature that affects it. Oxides of copper, aluminium, nickel, vanadium, lithium or manganese are used to make such elements. Depending on the chosen mixture, thermistors of different types and resistances can be created. There are three types - the most popular is NTC (negative temperature coefficient). It has a negative temperature coefficient, as a result of which a higher temperature results in a decreasing resistance (and a lower one - an increasing one). PTC (positive temperature coefficient) thermistors work exactly the opposite way: they have a positive temperature coefficient, which means that they achieve higher resistance at increasing temperature. The last type is CTR (critical temperature resistor) - these are thermistors that are characterized by sudden increases in resistance (depending on the material used, the reaction is an increase or decrease in resistance). Standard resistors also depend on the parameter of the temperature value, but the degree of dependence is much higher for thermistors. In a standard resistor, temperature-dependent resistance is an undesirable feature.

Application of thermistors

Thermistors are passive elements used in electronic circuits, which make it possible to determine the ambient temperature easily and quickly. They are a very cheap, robust and precise tool for such applications. All these advantages make them commonly used in electronic thermometers, for measuring the temperature of components and operating fluids in motor vehicles, refrigerators, ovens, microwaves and all types of domestic appliances where temperature measurement is required. It is also an excellent learning tool for electronics beginners or students of electronics-related fields of study (for example, automation and robotics or computer science). The thermistor can be, for example, a type of analogue sensor connected to a development board (Raspberry Pi, for example), which, based on room temperature readings, will give appropriate signals to devices such as a fan or air conditioner. Thermistors are also used in devices as a tool to compensate for changes in resistance, for example, due to a rise in temperature on a low frequency generator.

What products do you find in this category?

Chronic thermistors

Our offer includes mainly NTC (negative temperature coefficient) type thermistors. This means that the higher the ambient temperature, the lower the resistance of the thermistor. We have a wide range of small thermistors sold as a single element intended for threaded assembly (with legs of about 30 mm in length), but we also offer elements of this type equipped with a long cable and finished electronic circuits with built-in thermistors. They are sold separately and have an error tolerance of 5%. Their resistance values vary depending on the product - we offer thermistors with resistances of 1 kΩ, 2.2 kΩ, 5 kΩ, 10 kΩ, 22 kΩ, 47 kΩ and 100 kΩ.

Thermistors with cables

We also offer a thermistor with a resistance of 110 kΩ, which is equipped with a wire of about 160 mm and a connector for a screw with M6 thread. This type of thermistor can be particularly useful when the electronics engineer intends to precisely control the temperature of an object that is made of a material that is well-conducting. The thermistor can be easily screwed on, for example, a hot motor element to measure its temperature on the fly. We also offer thermistors equipped with long, two-wire cables of 300 cm, 100 cm or 50 cm in length. An example of this type of product is a thermistor with a resistance of 10 kΩ (with a 1% tolerance) and a diameter of 5 mm, connected to a one-meter long cable terminated with wires with insulation removed. The measuring range of the product is from -30°C to 280°C.

Thermistors in electronic circuits

We also offer ready-made temperature sensors ready for connection in any electronic system. Each of them is equipped with thermistors, which are able to measure temperature from -25°C to 125°C. Electronic circuits are prepared so that the user can comfortably use the outputs and connect it to the power supply (5 V) and to the analog input of any microcontroller (for example to Arduino development board). Reading its status will be equivalent to reading the current temperature value.