Picking the Perfect NTC Thermistor

ntc thermistorNTC thermistors are temperature-sensing devices that are designed with a semiconductor material. The semiconductor material is capable of showing variations in temperature by using a small, measured direct current. Essentially, thermistors are superbly accurate tools for measuring temperature change. These tools can sense overheating in electronics and subsequently protect circuits from overcompensation. There are many different NTC thermistors on the market, which can make shopping for one a difficult task. This article will help highlight different types of thermistors and their most suitable applications.

There are two types of NTC thermistors on the market. The main difference between the two is the way that the electrodes have been fixed to the ceramic section thermistor. The Bead type and chip thermistors have lead wires. The other type of thermistor is called the surface metal thermistor (SMD) and has metalized surface contacts. 

The best way to find the perfect thermistor is to consider different variables that are associated with thermistor types. The size of the device and physical characteristics are two basic facts that should be established prior to purchasing a thermistor.
When selecting a thermistor, the first step is to assess the type and size of the product. Thermistor users must know what is needed in terms of size and dimensions for the thermal response and additional physical features. Once this in narrowed down, choosing an NTC thermistor is much simpler.

The next factor to consider is the nominal resistance value. NTC thermistors are usually calibrated at 25 degrees Celsius, but there can be alternative options with different nominal resistance values.

After the nominal resistance value is determined, you want to look at standard resistance tolerances. Most thermistors have different zero-power resistances:

It is best to select the broadest tolerance for your intended application.

Beta tolerances are another factor to consider when purchasing an NTC thermistor. The metal oxides used in its creation determine the beta tolerance. Tolerances are different for metal-surface and bead-type thermistors. If an application has many high and low temperatures, it is beneficial to specify resistance during at operating temperature.

The last aspect you want to consider is calibration. There are many thermistors available with extremely accurate calibrations. Make sure to find out how to calibrate your thermistor before making a final purchase.


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