It has been a obstructor in application being the high resistivity at room temperature, the feeble PTC intensity and the poor reproducibility in our country.

• 我国在该领域的研究开发起步较晚，存在室温体积电阻率高、PTC强度低和热循环稳定性差等问题，成为制约其走向实用化的瓶颈。