| 摘要 |
PURPOSE:To enable the switching of DC power supply, by connecting a transistor in parallel with a contact connected to the power supply circuit of a load. CONSTITUTION:When a relay coil 1 is excited, a contact 4 is closed and a transistor (Tr)10 turns on, a load 5 is energized from a DC power supply 11, and after that a contact 3 is closed. Next, when the power supply to the load 5 is stopped, and when the excitation to the coil 1 is stopped, the contact 4 is opened after the contact 3 is opened. Then, Tr10 is OFF and the power supply to the load 5 is stopped. Thus, at the start and stop of power supply, only Tr10 is inserted to the power supply circuit and the contact 3 is also inserted to the power supply circuit during the power supply in other cases. Accordingly, no arc is produced to the contact 3 and switching for a large current can be made. |
