| 摘要 |
A floating transistorized switching circuit comprises an optical coupler for electrically isolating a source of control signals from the switching circuit; a floating DC voltage supply, electrically isolated from the AC power line, for providing positive and negative logic level operating voltages, referenced to whatever voltage appears at the output terminal of the switching circuit; an output stage including first and second NPN switching transistors connected in a Darlington configuration; and a logic network responsive to the output signal from the optical coupler going on for turning on the Darlington output stage, and to this output signal going off for turning off the Darlington output stage.
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