| 摘要 |
A method and apparatus for suppressing electrical transient signals, occurring on power lines, includes a clamping circuit for switching from a high impedance to a low impedance at a certain switching voltage, to suppress the transient signals. A first blocking circuit inhibits the clamping circuit from switching to maintain it at its high impedance during normal line voltage, and permits the clamping circuit to switch to its low impedance for clamping purposes responsive to an initial portion of a transient signal for initial suppression purposes. A second blocking circuit has a second low impedance, which is substantially lower than said first low impedance of the first blocking circuit, for inhibiting substantially the first blocking circuit from continuing to dissipate the transient signal following the initial time period, and for permitting the clamping circuit to suppress the transient signal following the initial time period. When coupled to a three conductor power line, unidirectional devices are employed to couple transient signals from any one of the three conductors of the power line, to the clamping circuit.
|
