| 摘要 |
A solid state relay comprising a pair of SCRs connected in inverse parallel relationship across a pair of output terminals adapted to be connected in series with a source of AC power and a load, each SCR having an anode connected to one of the pair of output terminals, a cathode connected to another of the pair of output terminals, and a gate terminal; a pair of MOSFETs connected as a bidirectional switch for providing a single current path connecting the gate terminals of each of the pair of SCRs, the bidirectional switch allowing current application to the gate terminals without generating switching noise; a pair of diodes allowing current to transfer in one direction from each of the output terminals to each of the gate terminals of the SCRs; a source of optically coupled input signals which are applied to rapidly enable the bidirectional switch to provide a current path to the gate terminals of the SCRs and to maintain the bidirectional switch in the on condition as long as an input signal is furnished by the source of input signals; and a bridge circuit for monitoring the voltage across the output terminals and allowing the signals from the source of input signals to rapidly enable the bidirectional switch only during a period in which the voltage across the output terminals is less than a preselected zero voltage window value.
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