| 摘要 |
In each path of an output stage there is provided a sensor from which the voltage is measured for feeding to an input of a differential amplifier (10). The amplifier output feeds a comparator (13) whose output controls an electric switch (16) in such a fashion that it charges an electric store (18). The charge voltage controls the standing current in the output stage via a regulator transistor (19) in such a way that the voltage sensed by the sensors, proportional to the standing current. The control of the switch (16) may occur during the zero-crossings of the signals fed to the output stage. A second controlled switch (20) may block the switch (16) while the output stage conducts using a timer (21,22).
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