The Use of PTC Thermistors

With the rapid development of science and technology, the use of electronic devices is becoming more and more extensive, and the performance is constantly improving. Take the thermistor as an example, it has the advantages of good stability, strong overload capacity, small size, convenient use and so on. This article will tell you about the the use of PTC thermistors.

PTC thermistors can be used to replace traditional fuses for overcurrent protection. PTC thermistors react not only to unacceptably high currents, but also to exceeding preset temperatures. They reduce current by adding resistance, thereby reducing power consumption.

The voltage-current characteristic curve of PTC thermistors makes them ideal for short-circuit or overcurrent protection devices. When connected in series with a load, the PTC thermistor is in a low resistance state with negligible current attenuation. When a short circuit or overcurrent condition occurs, the PTC thermistor will switch to a high resistance state, limiting the current well below normal operating levels. When the fault is removed, the PTC will return to a low resistance state, allowing the current to return to normal levels.

One thing to note is that while several PTC thermistors can be connected in series for temperature sensing applications, do not connect them in series for higher voltage ratings. Since no two components are alike, one tends to heat up faster than the other, thus limiting the current flowing through the other device, causing the entire available voltage to drop across a single device.

When a PTC thermistor is in series with the load, it has a high resistance response. So the large voltage should be chosen high enough. Possible supply voltage fluctuations must also be considered. The PTC thermistor must have sufficient current rating.

In addition, it is necessary to check whether there is a situation where the maximum allowable switching current is exceeded, and it must be ensured that the PTC thermistor is not overloaded due to excessive switching current. If there is a possible risk, it can be solved by placing a resistor in series with the thermistor.

Dongguan Zhixu Electronic Co., Ltd. (also JYH HSU(JEC)) has engaged in the electronic component industry for many years, and our technical engineers can help you solve related problems. When purchasing varistors, you need to find out whether the products come from regular manufacturers. A good varistor manufacturer can reduce many unnecessary troubles.

JEC has over 30 years of manufacturing experience in the electronic components industry. If you have technical questions or need samples, please contact us.