With the continuous advancement of communication equipment technology, the protection requirements for switching and outdoor equipment have also greatly increased. Use PTC thermistors to protect telephone lines, mainly for overcurrent caused by the following reasons:
Surge current caused by direct lightning strikes or lightning strikes of nearby telephone line equipment; AC induced voltage caused by the failure of adjacent power lines or railway systems; The telephone line is connected to the power line; Usually each telephone line is connected in series with a PTC thermistor. Even with primary protection (usually a gas discharge tube), the PTC thermistor must meet strict requirements. Due to voltage pulses of up to 2 kV, in order to withstand short-term induced voltages, PTC thermistors must have high withstand voltage capabilities. If there is primary protection in the circuit, the PTC thermistor withstand voltage of 200V~300V is sufficient. There is no primary protection in the circuit, and the withstand voltage of the PTC thermistor must be above 600V. YAXUN can produce a series of PTC thermistors that meet the above requirements.


Application range:
1. Program-controlled exchange
2. Distribution frame
3. Telephone
4. User communication terminal equipment
5. Communication base station equipment


Product parameters:
1. MZ23 series products are resin-coated lead type, MZ25 series products are non-coating
    Lead type, MZ26 series products are SMD type

2. Meet ITU-T K20 K21
     --Current impact (10/700μs 1.5-6000KV)
     --Electric high voltage induction (600V, 1A, 0.2S)
     -Power line connection (230V, 15min.)
3. Suitable for continuous work under 110/230VAC (high resistance state) voltage
4. Resistance tolerance is small (sub-resistance pairing)
5. Long-term stability
6. Fast response time
7. No need to set after product overload protection
8. Safety certification: UL/CUL: E243011
                                 TUV: R50187698