| 摘要 |
It is intended to supply especially a heating element which is supplied from an AC voltage source for plastic injection moulding, using a switch arrangement for switching on and off. A relay which is controlled as a function of a control signal and has a switch contact in the load circuit is allocated to the switch arrangement. According to the invention, the switch part of the semiconductor switch element is connected in parallel with the switch contact of the relay in the load circuit. The semiconductor switch element is switched into the conductive state before the relay in time when the load is switched on, and/or is switched into the blocking state after the relay in time when the load is switched off. The switch arrangement according to the invention is especially suitable for switching high currents and voltages, has a long life even with a large number of switching operations, and permits a voltage drop on the switch path in the load circuit which is as small as possible.
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