An improved electric circuit structure for short circuit protection is applicable to examining a device under test, comprising a circuit breaking element, a thermistor, a filtering and rectifying module and a capacitor. A first end of the circuit breaking element is connected to a power source. The filtering and rectifying module is connected to a second end of the circuit breaking element, a ground, a first end of the thermistor and a first end of the capacitor. A second end of the capacitor is connected to a second end of the thermistor. The capacitor is connected in parallel with the device under test. The circuit breaking element disclosed in the present invention is a ceramic tube fuse and forms an open circuit when the device under test forms a short circuit. Meanwhile, the ceramic tube fuse withstands voltage between its first and second end without generating any physical damage.

In an embodiment, an apparatus includes a source device including a first current limiter and a second current limiter in parallel with each other and a first transformer and a second transformer; a load device includes a third transformer and a fourth transformer in parallel with each other; and an Ethernet cable is electrically coupled between the source device and the load device, the Ethernet cable including first twisted pair lines and second twisted pair lines. A direct current (DC) voltage is provided to the first current limiter and the second current limiter, the first transformer is electrically coupled to an output of the first current limiter, and the second transformer is electrically coupled to an output of the second current limiter. The DC voltage is transmitted to the third transformer and the fourth transformer in parallel with each other via the first twisted pair lines and the second twisted pair lines. The first twisted pair lines and second twisted pair lines are included in an Ethernet cable electrically coupled between the source device and the load device.

Embodiments of an ESD protection device are described. In an embodiment, an ESD protection device includes a first voltage rail electrically connected to a first node, a second voltage rail electrically connected to a second node, and ESD cells connected between the first and second voltage rails and configured to shunt current in response to an ESD pulse received between the first and second nodes. Each of the ESD cells includes clamp circuits electrically connected to the second voltage rail, ballast resistors connected between the first voltage rail and the clamp circuits, where at least some of the ballast resistors are electrically connected to a third voltage rail, a driver circuit connected between the second and third voltage rails and configured to generate a driver signal, and an output stage configured to generate an output signal in response to the driver signal.

The present invention provides a surge protection module which comprises a carrier board and a probe set. The carrier board is used to carry an electronic component. The probe set is disposed on the carrier board and has a plurality of probes and a short-circuit unit. Each probe is used for contacting the electronic component, and the short-circuit unit is selectively moved to a first position or a second position. When the short-circuit unit is moved to the first position, the short-circuit unit simultaneously contacts and shorts the plurality of probes. When the short-circuit unit is moved to the second position, the short-circuit unit is away from at least one of the plurality of probes.

Surge protection circuitry includes a pair of series connected diodes sharing a first common terminal that is directly electrically connected to only one of a pair of transmission lines, a pair of series connected Zener diodes, in parallel with the series connected diodes, sharing a second common terminal that is directly electrically connected to only the other of the transmission lines, and a pair of series connected power supplies each configured to reverse bias one of the series connected diodes such that the diodes prevent electrical coupling of the Zener diodes to the transmission lines responsive to a voltage of the signal source being less than a threshold value, and the diodes permit electrical coupling of at least one of the Zener diodes to the transmission lines responsive to the voltage being greater than the threshold value.

An overvoltage absorption circuit and a single-phase HERIC topology are provided. The overvoltage absorption circuit is applicable to the single-phase HERIC topology, and includes a clamping capacitor, an absorption resistor, a first diode, and a second diode. One terminal of the clamping capacitor and one terminal of the absorption resistor are each connected to collectors of two cross transistors in the single-phase HERIC topology. The other terminal of the clamping capacitor and the other terminal of the absorption resistor are each connected to the anodes of the first diode and the second diode. The cathode of the first diode is connected to the emitter of one of the two cross transistors. The cathode of the second diode is connected to the emitter of the other of the two cross transistors.

A storage compartment is provided. The device includes a housing unit with a door. The housing unit is designed to be concealed within a wall. The housing unit is secured to the wall by a plurality of fasteners. The door is pivotally connected to the housing unit via a plurality of hinges. The door provides access to an interior volume of the housing unit. The door includes more than one spring-loaded latch that secures the door to the housing unit. A plurality of electrical outlets is disposed on the interior walls of the housing unit. A recessed area of the housing unit provides a storage area for electrical cords, surge protectors, and other items. The door includes an aperture that allows for electrical cords within the storage area to be accessed when the door is closed.

An improved electric circuit structure for short circuit protection is applicable to examining a device under test, comprising a circuit breaking element, a thermistor, a filtering and rectifying module and a capacitor. A first end of the circuit breaking element is connected to a power source. The filtering and rectifying module is connected to a second end of the circuit breaking element, a ground, a first end of the thermistor and a first end of the capacitor. A second end of the capacitor is connected to a second end of the thermistor. The capacitor is connected in parallel with the device under test. The circuit breaking element disclosed in the present invention is a ceramic tube fuse and forms an open circuit when the device under test forms a short circuit. Meanwhile, the ceramic tube fuse withstands voltage between its first and second end without generating any physical damage.

An AC disconnect switch with integral surge protection. The intrinsic pullout head of the AC disconnect switch embodies a surge protection device, thereby eliminating the need for an extrinsic surge protection device.

An AC disconnect switch with integral surge protection. The intrinsic pullout head of the AC disconnect switch embodies a surge protection device, thereby eliminating the need for an extrinsic surge protection device.