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A brief analysis of the precautions to take when using negative temperature coefficient thermistors.

2025-01-02

NTC is known as a negative temperature coefficient thermistor, which is made by thoroughly mixing and sintering ceramic materials with manganese cobalt nickel oxide. It has the characteristics of small fluctuations in resistance-temperature characteristics and a quick response to various temperature changes.

It can be used as a high-sensitivity, high-precision temperature sensor, commonly used for real-time temperature monitoring in electronic circuits. As body temperature rises, the resistance of the NTC decreases non-linearly, which is a characteristic of NTC.

Its working principle is to prevent the surge current that occurs at the moment of starting in electronic circuits. Please connect the power-based NTC thermistor to the power circuit to effectively suppress the surge current during startup. After completing the surge current suppression function, the continuous action of the current makes the resistance of the power-type thermistor very small, which does not affect the normal working current. Therefore, using a power-type NTC thermistor in the power circuit is the simplest and most effective measure to suppress startup surge current and protect electronic devices from damage.

Therefore, there are details to pay attention to when using negative temperature coefficient thermistors. Otherwise, the negative temperature coefficient thermistor can be easily damaged. Here are several aspects summarized by the editor that need attention.

1. Pay attention to the working temperature of the negative temperature coefficient thermistor.

Do not use the NTC thermistor outside its working temperature range. The working temperature range for φ5, φ7, φ9, φ11 series is -40 to 150 degrees. The working temperature range for φ13, φ15, φ20 series is -40 to 200 degrees.

2. Use the NTC thermistor at its rated power.

The maximum rated power for each specification is 5-0.7W, 7-1.2W, 9-1.9W, 11-2.3W, 13-3W, 15-3.5W, 20-4W.

3. Precautions for use in high temperature and high humidity environments.

If it is necessary to use the thermistor in a high temperature and high humidity environment, please use an external thermistor to expose the protective film-sealed part to the environment (water, humidity), and ensure that the open part of the sheath does not come into direct contact with water and steam.

4. It cannot be used in environments with harmful gases and liquids.

Do not use in environments with corrosive gases or in contact with electrolytes, saltwater, acids, bases, and organic solvents.

5. Protect the wires.

Do not overstretch or bend the wires and avoid applying excessive vibration, impact, and pressure.

6. Keep away from heat-generating electronic components.

It is recommended not to install heat-generating electronic components around the power-type negative temperature coefficient thermistor. Use products with higher upper parts on bent legs, and place other components on the circuit board using the NTC thermistor to ensure that heat does not affect the normal operation of other components.

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