| 摘要 |
<p>A line protector is provided which includes positive temperature coefficient resistors in the circuit which are thermally coupled to voltage clamping devices which require protection from failures caused by overheating from conducting excessive amounts of current for a time sufficient to cause device breakdown. This may compensate for the performance variability of the positive temperature coefficient resistors so as to improve the likelihood that they will experience a sufficient temperature increase to switch before the voltage clamping device reaches a breakdown temperature. Furthermore, a line protector which may provide protection against current flow to the communications circuit from overvoltage conditions on the circuit side of the line protector or by a ground potential difference between the line protector and the communications circuit is also provided including positive temperature coefficient resistors positioned between the overvoltage line protector circuits and the communications circuit.</p> |
