| 摘要 |
A control circuit for accurately controlling the duration of a welding operation. In a preferred embodiment the control circuit includes first and second connectors for connecting the control circuit to a power source, welding and control transformers, the first connector being connected to the first terminals of the primary windings of the transformers and the second connector being connected to the second terminal of the primary winding of the control transformer, a trigger circuit portion including an operator actuatable switch connected across the secondary winding of the control transformer and producing a signal in response to actuation of the operator actuatable switch, a timing control circuit portion connected in parallel with the trigger circuit portion and including a multiposition switch selectively settable for establishing a desired weld time interval and another circuit portion operatively connected to the trigger circuit portion to respond to signals therefrom and to weld time interval switch settings to generate weld output signals, and a gating circuit portion under control of a control input thereof connected to receive weld output signals from the control circuit portion for controlling electrical communication between the second terminal of the primary winding of the welding transformer and the second connector so as to complete a power circuit through the primary winding of the welding transformer thereby establishing a welding circuit voltage potential across the secondary winding of the welding transformer, the duration of application of the welding circuit voltage potential being controlled by the setting of the multiposition switch.
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