Provided is a sensor device wherein malfunction due to a negative surge is suppressed. This sensor device is provided with: a sensor element wherein electrical characteristics change corresponding to physical quantities; a signal processing circuit that processes output signals of the sensor element; a first transistor element that supplies currents to the sensor element and the signal processing circuit; a control circuit that controls a base current of the first transistor element; a power supply terminal; and a ground terminal. The sensor device is characterized in that the control circuit is provided with a limiting section that limits a current flowing from the ground terminal toward a base terminal of the first transistor element.

A surge protective device with an independent chamber comprising a fuse for overcurrent protection is disclosed. It comprises a first chamber for receiving a voltage sensitive element with a thermal protection switch, and a second chamber independent from the first chamber and provided in the external of the first chamber. The second chamber contains a fuse for power frequency overcurrent protection in series connection with the voltage sensitive element. The surge protection device comprises an independent chamber for power frequency overcurrent protection at outside of the thermal protection device, so as to avoid interference with the components around the fuse. In addition, when the MOV is unexpectedly punctured and got short circuit, the device of the present invention still operates to protect the surge protective surge.

A surge protection device includes an isolating transformer configured to conduct an Ethernet data signal on a wire pair and configured to provide voltage surge protection for Ethernet equipment coupled to the wire pair, and a power supply coupled to the isolating transformer and configured to conduct a DC voltage signal from the wire pair and configured to provide voltage surge protection for the Ethernet equipment coupled to the wire pair.

A surge protection device includes an isolating transformer configured to conduct an Ethernet data signal on a wire pair and configured to provide voltage surge protection for Ethernet equipment coupled to the wire pair, and a power supply coupled to the isolating transformer and configured to conduct a DC voltage signal from the wire pair and configured to provide voltage surge protection for the Ethernet equipment coupled to the wire pair.

An equipotential bonding system can be provided for a lightning protection system that includes a mast assembly with an internal passageway that includes an internal surface, and a conductor that extends through the internal passageway. The equipotential bonding system can include a deflection member that is disposed at least partly within the internal passageway. The deflection member can be configured to urge the conductor into contact with the internal surface to form a conductive pathway between the mast assembly and the conductor.

An equipotential bonding system can be provided for a lightning protection system that includes a mast assembly with an internal passageway that includes an internal surface, and a conductor that extends through the internal passageway. The equipotential bonding system can include a deflection member that is disposed at least partly within the internal passageway. The deflection member can be configured to urge the conductor into contact with the internal surface to form a conductive pathway between the mast assembly and the conductor.

A surge suppression system provides surge protection both locally within the radio station building were the power plant and telecommunication equipment are located and remotely next to the radios and antennas located outside of the building on the communication tower. An external surge suppression unit provides a waterproof enclosure for both surge suppression devices and fiber optic connectors. A rack mountable surge suppression unit provides local in-line surge suppression protection for the electrical equipment located in the communication station. A unique surge suppression tray is hot swappable so that multiple surge suppression devices can be replaced at the same time without disrupting radio operation. Pluggable surge suppression modules can be used in both the external surge suppression unit and the rack mountable surge suppression unit.

A T-type DC circuit breaker includes a main branch, a first commutation switch, a second commutation switch, and a bypass branch. The first commutation switch and the second commutation switch are arranged at both ends of the main branch, respectively. The bypass branch is connected in parallel with the main branch. The main branch includes at least one half-controlled power electronic component. The bypass branch includes a bypass capacitor and a bypass diode connected in series. Each of the first commutation switch and the second commutation switch includes at least one fully-controlled power electronic component. The first commutation switch is connected in parallel with a first surge arrester, and the second commutation switch is connected in parallel with a second surge arrester. The grounded branch is arranged between the main branch and the second commutation switch and is grounded or connected to the negative terminal of the load.

A T-type DC circuit breaker includes a main branch, a first commutation switch, a second commutation switch, and a bypass branch. The first commutation switch and the second commutation switch are arranged at both ends of the main branch, respectively. The bypass branch is connected in parallel with the main branch. The main branch includes at least one half-controlled power electronic component. The bypass branch includes a bypass capacitor and a bypass diode connected in series. Each of the first commutation switch and the second commutation switch includes at least one fully-controlled power electronic component. The first commutation switch is connected in parallel with a first surge arrester, and the second commutation switch is connected in parallel with a second surge arrester. The grounded branch is arranged between the main branch and the second commutation switch and is grounded or connected to the negative terminal of the load.

A circuit protection device is provided. The circuit protection device includes an active energy absorber that is coupled between two power lines in an electrical power distribution system and is configured to selectively conduct fault current responsive to overvoltage conditions. The active energy absorber includes an overvoltage protection module that includes two thyristors that are connected in anti-parallel with one another and a varistor that is connected with the overvoltage protection module as a series circuit. The series circuit including the varistor and the overvoltage protection module is connected between the power lines.