| 摘要 |
A time delay relay circuit of the present invention includes a power supply terminal, a relay having a first terminal connected to the power supply terminal, and a timing circuit, for activating the relay for a preset duration, having a supply input for receiving power for the timing circuit. Also included is a means for connecting the supply input of the timing circuit to the power supply terminal during operation of the timing circuit and activation of the relay and disconnecting the supply input of the timing circuit from the power supply terminal during non-operation of the timing circuit. The means connecting the supply input to the power supply terminal may be a switch which is closed and opened to start the preset duration time running within the timing circuit. During the preset duration, the switch remains open. The relay is closed making a connection between the power supply terminal and the supply input. In a preferred embodiment, a pair of diodes are arranged such that current is prevented from flowing toward the switch when the relay is closed and current is prevented from flowing toward the load when the relay is open. The time delay relay circuit prevents current flow through the circuit when the circuit is connected to a power supply and not in use.
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