● Basic principles
The full name of polymer PTC is "polymer positive temperature coefficient thermistor", which has excellent overcurrent protection function due to the special properties of its material. Polymer PTC is connected in series in the circuit (as shown in Figure 1), and under normal circumstances, it is in a low resistance state, and the working current can pass smoothly; When an abnormally high current occurs in the circuit, its impedance rapidly increases (in a high resistance state), effectively limiting the passage of high current and protecting the circuit from damage (as shown in Figure 2). After the fault current is eliminated, the resistance of the polymer PTC rapidly decreases and returns to a low resistance state.

Figure 1 Figure 2 ● Selection Guide
The use of polymer PTC is both safe and convenient, and is a win-win strategy. When selecting, the first consideration should be that the operating voltage should be less than or equal to the maximum voltage that the polymer PTC can accommodate; Next is to match the size of the working current. The working current (IH) listed in the specification refers to the current value at a working environment temperature of 25 ℃. If the actual working environment temperature is different from it, temperature current reduction factors should also be considered, as shown in Figure 3. Finally, the installation method should also be considered, such as plug-in and optical chip insertion. Other technical indicators refer to the specification sheet. If there are any special circumstances, please contact our company directly to inquire about special processing.

● Application scope:
The U30 series products are widely used in circuits with medium voltage resistance, such as micro motors, computer interfaces, mice, etc CPU、 In the fields of transformers, security equipment, testing and measurement equipment, satellite receiving systems, toy industry, etc.