Yes PTC is a current-limiting protection device, and its working temperature is TS. When its internal temperature is lower than ts, its resistance value remains basically unchanged. The resistance at this time is called cold resistance. The current needs to be limited. "Current limiting" refers to limiting the amount of content pushed by bloggers in Weibo and other social software for a certain period of time, resulting in a decline in popularity. "Current limiting" refers to limiting the rate of data traffic, which can be understood as a traffic shaping, a network traffic management technology of computer networks.