Combining overcurrent and overvoltage circuit protections, this creates a device which will open if subjected to continuous over current, thus protecting the MOV and greatly reducing the risk of catastrophic failures.

MOV (Metal Oxide Varistor) has been a common solution for overvoltage circuit protection, it’s cost effective and  ideal for transient surge protection. However, a prolonged or repetitive overvoltage event will generate a overcurrent which will lead to thermal runaway. 

PPTC combined with MOV, when overvoltage strikes, resistance drops and overcurrent occurs, PPTC limits the overcurrent and protect MOV.

Please refer to the attached file for more information.