A relay device includes a coil portion, a fixed contact, a spring, a moving contact and a drive circuit. The drive circuit controls the electromagnetic force of the coil portion to be a first electromagnetic force when switching the fixed contact and the moving contact in a contact state to a non-contact state. The drive circuit controls the electromagnetic force of the coil portion to be a second electromagnetic force that is larger than the first electromagnetic force after a lapse of a first time from start of control of the electromagnetic force of the coil portion to be the first electromagnetic force. The drive circuit controls the electromagnetic force of the coil portion to be reduced with time after a lapse of a second time from start of control of the electromagnetic force of the coil portion to be the second electromagnetic force.

A power supply circuit, a relay device and a Power over Ethernet system related to the electronic technical field are provided. In the power supply circuit, each rectifier module has its positive output end connected to a positive supply pin, and a negative output end connected to a first end of a switch control module. The positive supply pin is connected to a positive terminal of a relay circuit in the relay device. The switch control module has a second end connected to a negative supply pin, and a control end connected to the positive supply pin. The negative supply pin is connected to a negative terminal of the relay circuit. The switch control module allows conduction between the first end and the second end when the rectifier module outputs a voltage greater than a preset threshold.

A power supply circuit, a relay device and a Power over Ethernet system related to the electronic technical field are provided. In the power supply circuit, each rectifier module has its positive output end connected to a positive supply pin, and a negative output end connected to a first end of a switch control module. The positive supply pin is connected to a positive terminal of a relay circuit in the relay device. The switch control module has a second end connected to a negative supply pin, and a control end connected to the positive supply pin. The negative supply pin is connected to a negative terminal of the relay circuit. The switch control module allows conduction between the first end and the second end when the rectifier module outputs a voltage greater than a preset threshold.

A relay device includes a coil portion, a fixed contact, a spring, a moving contact and a drive circuit. The drive circuit controls the electromagnetic force of the coil portion to be a first electromagnetic force when switching the fixed contact and the moving contact in a contact state to a non-contact state. The drive circuit controls the electromagnetic force of the coil portion to be a second electromagnetic force that is larger than the first electromagnetic force after a lapse of a first time from start of control of the electromagnetic force of the coil portion to be the first electromagnetic force. The drive circuit controls the electromagnetic force of the coil portion to be reduced with time after a lapse of a second time from start of control of the electromagnetic force of the coil portion to be the second electromagnetic force.

A power supply circuit, a relay device and a Power over Ethernet system related to the electronic technical field are provided. In the power supply circuit, each rectifier module has its positive output end connected to a positive supply pin, and a negative output end connected to a first end of a switch control module. The positive supply pin is connected to a positive terminal of a relay circuit in the relay device. The switch control module has a second end connected to a negative supply pin, and a control end connected to the positive supply pin. The negative supply pin is connected to a negative terminal of the relay circuit. The switch control module allows conduction between the first end and the second end when the rectifier module outputs a voltage greater than a preset threshold. The power supply circuit can supply power to the relay circuit of the relay device without increasing power wiring and affecting the normal power supply of the powered device by the power sourcing equipment. This improves the application flexibility of the POE technology.

A power supply circuit, a relay device and a Power over Ethernet system related to the electronic technical field are provided. In the power supply circuit, each rectifier module has its positive output end connected to a positive supply pin, and a negative output end connected to a first end of a switch control module. The positive supply pin is connected to a positive terminal of a relay circuit in the relay device. The switch control module has a second end connected to a negative supply pin, and a control end connected to the positive supply pin. The negative supply pin is connected to a negative terminal of the relay circuit. The switch control module allows conduction between the first end and the second end when the rectifier module outputs a voltage greater than a preset threshold. The power supply circuit can supply power to the relay circuit of the relay device without increasing power wiring and affecting the normal power supply of the powered device by the power sourcing equipment. This improves the application flexibility of the POE technology.

An electrical storage system includes an electrical storage device, a load, a positive electrode line, a negative electrode line, a first relay, a second relay, a third relay, a drive circuit and a controller. The drive circuit includes a coil, a first power line, a second power line, and a sensor. The first power line includes a first switch element and a second switch element connected in series with each other. The second power line includes a second resistive element and a third switch element connected in series with each other. The drive circuit is configured to cause both the second and third relays and the first relay to operate at different timings. The controller is configured to control operation of the drive circuit. The controller is configured to output a control signal for setting each switch element to the non-energized state, and determine whether any one of the switch elements has a failure in the energized state on the basis of the output signal of the sensor.

An electrical storage system includes an electrical storage device, a load, a positive electrode line, a negative electrode line, a first relay, a second relay, a third relay, a drive circuit and a controller. The drive circuit includes a coil, a first power line, a second power line, and a sensor. The first power line includes a first switch element and a second switch element connected in series with each other. The second power line includes a second resistive element and a third switch element connected in series with each other. The drive circuit is configured to cause both the second and third relays and the first relay to operate at different timings. The controller is configured to control operation of the drive circuit. The controller is configured to output a control signal for setting each switch element to the non-energized state, and determine whether any one of the switch elements has a failure in the energized state on the basis of the output signal of the sensor.

A circuit for preventing sparks. The circuit having a power storage component having a first power storage end and a second power storage end; a power source electrically connected to the power storage component, the power source having a first power source end and a second power source end; a first current directional component electrically connected to the power storage component and having a first current direction; a first power absorption component electrically connected to the power storage component and having a current direction, the first current directional component and the first power absorption component being electrically connected to the power storage component in parallel; and at least one switch electrically connected to the power storage component.