Abstract: The present invention relates to a polymer fuse apparatus that provides bypass fuse protection. A polymer bypass fuse is comprised of an electrical conductor wherein a portion of the conductor is surrounded by an internal electrode, which is then surrounded by a layer of polymeric positive temperature coefficient (PTC) material, which is then surrounded by a conductive material similar to that of the internal electrode.

Abstract: A surge protection device includes terminals adapted to receive a power source voltage and surge protection circuits, each of which includes a thermal fuse spring, one or more metal oxide varistors (MOVs), and one or more fuse traces corresponding to the MOVs. The thermal fuse spring, one of the fuse traces and the corresponding one of the MOVs are electrically interconnected in series between the terminals, in order to form a series electrical connection therebetween. The thermal fuse spring is adapted to disconnect the series electrical connection between the terminals under first fault conditions including a first current of first duration through one of the MOVs. The thermal fuse spring and each of the fuse traces are adapted to cooperatively disconnect a corresponding one of the series electrical connections between the terminals under second fault conditions including a second greater current of second lesser duration through one of the MOVs.

Abstract: An electrical device includes a housing with first and second portions. Each of the first and second portions has a first insulative layer and a second conductive layer. The first and second layers define an inner cavity. The second portion has opposing first and second lateral sides with the first layer defining a first thickness at the first lateral side and a second thickness at the second lateral side. An electrically conductive member is received within the inner cavity in the first portion. At least one electrical component is received within the inner cavity at the second portion. A weak section is defined by the first thickness at the first lateral side being substantially less than the second thickness at the second lateral side diametrically opposite it at given points along a longitudinal axis of the second portion.

Abstract: A method for protecting a printed wiring board (PWB) and the electrical components mounted on the PWB from high temperature, fire, plasma and debris resulting from a catastrophic failure of an at-risk electronic component located on the PWB or in close proximity to the PWB. This protection is provided by a layer of inorganic refractory material applied to a surface of the PWB adjacent the at-risk electrical component. The refractory material is preferably applied to the PWB surface as a pourable liquid. The refractor material must have sufficient viscosity such as to easily flow in and around electronic components located on the PWB and be self-leveling before curing, so as to produce a uniform thickness. The refractory material should also have a small shrinkage factor when cured such that no gaps are created between the PWB and the enclosure and around the electrical terminals of the at-risk components.

Abstract: An overvoltage arrester for high or medium voltage is described which includes an arrester block arranged inside a sealed, gas-tight enclosure housing, a sensor, in 5 particular a temperature sensor in the form of a surface wave sensor, is arranged inside the enclosure housing. The surface wave sensor is arranged in a housing that is designed as an antenna.

Abstract: An overvoltage protection device includes a housing including a first substantially planar electrical contact surface and a sidewall. The housing defines a cavity therein and has an opening in communication with the cavity. An electrode member of the device includes a second substantially planar electrical contact surface facing the first electrical contact surface and disposed within the cavity. A portion of the electrode member extends out of the cavity and through the opening. A wafer formed of varistor material and having first and second opposed, substantially planar wafer surfaces is positioned within the cavity and between the first and second electrical contact surfaces with the first and second wafer surfaces engaging the first and second electrical contact surfaces, respectively.

Abstract: A voltage suppression device for suppressing voltage surges in an electrical circuit, comprised of a voltage sensitive element having a predetermined voltage rating, the voltage sensitive element increasing in temperature as voltage applied across the voltage sensitive element exceeds the voltage rating. Terminals are provided for electrically connecting the voltage sensitive element between a power line of an electrical circuit and a ground or neutral line of the electrical circuit. A normally closed, thermal switch is electrically connected in series with the voltage sensitive element between the power line and the voltage sensitive element, the thermal switch being thermally coupled to the voltage sensitive element wherein the thermal switch moves from a normally closed position to an open position to form a gap between the thermal switch and the voltage sensitive element when the temperature of the voltage sensitive element reaches a level indicating an over-voltage condition.

Abstract: A surge arrester includes an electrically insulating arrester housing and a surge arresting block housed within the electrically insulating arrester housing. The surge arresting block is arranged to provide support for the surge arrester without the use of a support member. The surge arresting block may be a single surge arresting block having a voltage rating of at least 9 KV. The surge arresting block may have threads formed integrally therewith.

Abstract: The present invention provides an ESD structure that can tolerate voltages at the I/O pin, or pad, higher than the voltage allowed for such technology. More particularly, the present invention provides an electrostatic discharge integrated circuit having a first and second NMOS transistor, a first and second voltage divider, a first and second steady state biasing circuit. The first NMOS transistor sinks electrostatic discharge current from an input/output pad to a ground source, the first NMOS transistor having a drain coupled to the input/output pad, and a gate. The first voltage divider has a node connected to the gate of the first NMOS transistor. The first steady state biasing circuit connects to the gate of the first NMOS transistor. The second NMOS transistor sinks electrostatic discharge current from the input/output pad to the ground source, the second NMOS transistor having a drain coupled to a source of the first NMOS transistor, and a source coupled to the ground source.

Abstract: An electrostatic discharge device adapted to be mounted to an electrical fixture wallplate is disclosed. The discharge device consists of a circuit having at least a resistor and preferably a non-linear discharge component mounted on an electrical fixture wallplate. Another embodiment has an electrical discharge circuit built within an electrical switch.

Abstract: An electrical service apparatus housing carries a plurality of line and load blade terminals and jaw contacts. Surge suppression elements are carried on a circuit board mountable within the housing and are connected to certain blade terminals and jaw contacts for conducting electrical surges to ground. Insulating barriers surround the jaw contacts and, also, fixedly position the circuit board in the housing. A switch element is energized when one of the surge suppression elements changes state and provides an externally transmittable signal indicative of the change in state of one of the surge suppression elements. An insulating safety shield surrounds the jaw contacts. A light transmissive guide carried on the shield has a first end disposed adjacent to a light source on the circuit board and an opposed second end visible exteriorly through the housing to provide an exteriorly visible indication of the state of the light source.

Abstract: A transient voltage surge suppressor (TVSS) having a fuse rated to withstand high transient surge currents is disclosed. The TVSS employs metal oxide varistors (MOV's) in close proximity to the fuse such that heat from failed MOV's is used to reduce the time required to blow the fuse. The fuse may be mounted to the metal bus connection of a MOV within a sand-filled or potted box containing the MOV's. Thus, the TVSS of the present invention utilizes a thermally assisted disconnect method which enhances the performance of the TVSS under unusual fault conditions.

Abstract: An electrical surge arrester is manufactured by securing a stack of metal oxide varistor blocks between end terminations by passing a rod through through-holes in the varistor blocks and securing the ends of the rod to the end terminations. The through-holes are larger than the rod cross-section and a silicone rubber material is injected into the void which otherwise would exist between the rod and the interior surfaces of the through-holes in the varistor blocks. The silicone rubber material is also moulded around the exterior of the stacked varistor blocks and forms a shedded external housing for the arrester. The silicone rubber coatings on the varistor block internal and external surfaces effects a passivation function and means that the passivation coatings normally provided on the surfaces of varistor blocks by their manufacturers at significant cost can be omitted.

Abstract: A surge arrester includes a mounting bracket, a surge arresting element, an electrically conductive connector, and a fault disconnector. The mounting bracket forms a bracket cup. The surge arresting element is arranged to conduct in the presence of a surge. The electrically conductive connector is electrically coupled to the surge arresting element and forms a connector cup. The electrically conductive connector is received by the mounting bracket so that the bracket cup is received in the connector cup. The fault disconnector is arranged to disconnect the surge arresting element from an electrical line in the event of a fault, and the fault disconnector is housed within the housing formed by the connector cup and the bracket cup.

Abstract: The present invention relates to a polymer fuse apparatus that provides bypass fuse protection. A polymer bypass fuse is comprised of an electrical conductor wherein a portion of the conductor is surrounded by an internal electrode, which is then surrounded by a layer of polymeric positive temperature coefficient (PTC) material, which is then surrounded by a conductive material similar to that of the internal electrode. Various hybrid combinations are also contemplated where in-line and/or bypass fuses are combined with other circuit components. One example is, a plurality of in-line and bypass fuses combined with a differential and common mode filter, which itself consists of a plurality of common ground conductive plates maintaining first and second electrode plates between the various conductive plates, all of which are surrounded by a material having predetermined electrical characteristics to provide fail safe filter and circuit protection.

Abstract: An electrical component assembly includes a first printed circuit board (PCB) having a plurality of first-PCB conductive paths communicating with the surface of the first PCB, the assembly also includes at least one additional PCB having a plurality of additional-PCB conductive paths communicating with the surface of the PCB, with the conductive paths located such that when the additional PCBs and the first PCB are positioned one on top of the other, the conductive paths of the PCBs are substantially aligned, the conductive paths being formed from solder-filled vias passing through the PCBs and electrically-conductive junction pads positioned on the surface of the PCBs. The assembly also includes a plurality of electrical circuit components, wherein each component is electrically connected to a conductive path of one of the PCBs at one end and to a conductive path of another of the PCBs at the other end, the assembly also includes a plurality of traces that connect conductive paths.

Abstract: A suspension device for a line arrester in an air-insulated transmission line including two suspension parts which support the line arrester such that its longitudinal axis deviates from the vertical line. One of the suspension parts includes a disconnecting device which, when releasing, permits the line arrester a swinging motion under the influence of a force of gravity caused by the weight of the line arrester itself. And, one of the suspension parts includes a damping member which influences the line arrester with a force directed against the swinging motion during at least part of the swinging motion. The damping member may include a damping plate, one or more friction linings, or a flexible wire.

Abstract: The present invention relates to a passive electronic component architecture employed in conjunction with various dielectric and combinations of dielectric materials to provide one or more differential and common mode filters for the suppression of electromagnetic emissions and surge protection. The architecture allows single or multiple components to be assembled within a single package such as an integrated circuit or connector. The component's architecture is dielectric independent and provides for integration of various electrical characteristics within a single component to perform the functions of filtering, decoupling, fusing and surge suppression, alone or in combination.

Abstract: Overvoltage-protection device, applicable in particular to the low-voltage mains, comprising, between the two lines (1, 2) of the mains, a gas-discharge arrestor (3), a varistor (4) and a thermal-fuse element (5) tasked with ensuring the thermal disconnection of the device. It includes, in parallel with the varistor (4), a resistor (7) causing, after the short-circuiting of the gas-discharge arrestor (3), the heating of the thermal-fuse element (5) so as to trigger the thermal disconnection of the device.

Abstract: A voltage non-linear resistor unit is composed of at least one of voltage non-linear resistors which is composed of a columnar sintered body formed by molding and sintering a raw material, the sintered body having both end surfaces having a surface roughness in term of arithmetic average surface roughness Ra of 1 to 2 &mgr;m and being formed with an electrode film layer, a terminal metal fitting formed in a predetermined shape and attached to the voltage non-linear resistor, and a soldering material arranged between the voltage non-linear resistors and between joint surfaces of the voltage non-linear resistor and the terminal metal fitting, the joint surfaces being joined by heating the soldering material and applying a load vertically to the joint surfaces while giving a rotation motion thereto. Such voltage non-linear resistor is effectively assembled into an arrester.

Abstract: A method and apparatus for mounting heat generating components on a printed circuit board. Components mounted on the printed circuit board that generate heat may alter the properties of the printed circuit board and allow the printed circuit board to conduct current. To stop the flow of current in the printed circuit board, a slot may be used between the mounting points of the component. The slot prevents current from flowing within the printed circuit board.

Abstract: A varistor has a thermal fuse between a lead and an electrode. The fuse includes a link extending between the surface of an insulator and the fused electrode. The electrical connection of the link and the electrode is maintained by a low temperature solder fillet. That part of the link between the electrode and the insulator is surrounded by hot melt electrically insulating material. Upon sustained over-voltage conditions, the link and the solder fillet melt, and an insulating gap is rapidly created by molten hot melt material.

Abstract: The surge arrester has an arrester housing, two electrical power connections (16, 17) which are routed out of the arrester housing, and at least one varistor, which is arranged in the arrester housing (1, 2), is in the form of a disc and has two contact points which are provided on the end faces. The contact points are each electrically conductively connected to one of the two electrical power connections (16, 17).

Abstract: The present invention relates to a polymer fuse apparatus that provides bypass fuse protection. A polymer bypass fuse is comprised of an electrical conductor wherein a portion of the conductor is surrounded by an internal electrode, which is then surrounded by a layer of polymeric positive temperature coefficient (PTC) material, which is then surrounded by a conductive material similar to that of the internal electrode. Various hybrid combinations are also contemplated where in-line and/or bypass fuses are combined with other circuit components. One example is, a plurality of in-line and bypass fuses combined with a differential and common mode filter, which itself consists of a plurality of common ground conductive plates maintaining first and second electrode plates between the various conductive plates, all of which are surrounded by a material having predetermined electrical characteristics to provide fail safe filter and circuit protection.

Abstract: A variable voltage protection component is provided with a reinforcing layer of insulating material having a substantially constant thickness embedded in a voltage variable material. The reinforcing layer defines a uniform thickness for the variable voltage protection component that is resistant to compressive forces that may cause a reduction in the clamp voltage or a short in the voltage variable material. In addition, the variable voltage protection device component can be attached to a compressible ground plane to form a variable voltage protection device.

Abstract: An apparatus and method for protecting hardware devices using a spiral inductor. The surge suppressor protects hardware devices from electric surges by isolating the radio frequency from an inner conductor. The surge suppressor includes a housing, an inner conductor, a surge blocking device, and a spiral inductor. The surge blocking device is inserted in series with the hardware devices for blocking the flow of electrical energy therethrough. The spiral inductor is coupled to the surge blocking device and is shunted to ground for discharging the electrical surge.

Abstract: The present invention is a surge protector circuit and method of protecting electronic equipment which do not load down a circuit at high frequencies and do not degrade a signal in high speed data transmission. A gas tube is connected in parallel with low capacitance diodes and an avalanche semiconductor device, such as a TVS. The diodes and the avalanche semiconductor clamp the voltage transient and allow the slower gas tube more time to fire, discharging the surge. The addition of the low capacitance diodes in series with the avalanche semiconductor, reduces the line-to-line and line-to-ground capacitances of the surge protector and keeps the surge protector circuit from loading down the rest of the circuit and degrading the signal.

Abstract: A discharge counter relating to an operation of a lightening arrester to protect a power system and electric apparatus from overvoltage. This discharge counter includes a lightening arrester terminal, a grounding terminal, a nonlinear resistor connected between the lightening arrester terminal and the grounding terminal, a capacitor connected to the nonlinear resistance in parallel between the lightening arrester terminal and the grounding terminal, and a counter for counting the number of times a discharge current flows from the capacitor. Further, the counter is connected in parallel to the nonlinear resistance and capacitor. The nonlinear resistor includes a nonlinear material. That is, the nonlinear material is equal to a nonlinear resistance which includes zinc oxide as a main component and bismuth oxide and titanium oxide as a sub component, which have an excellent characteristic for the discharge counter.

Abstract: A surge suppressor and method for its manufacture. The surge suppressor includes a housing, a plurality of terminal busses contained within the housing, and a plurality of substantially planar conductive plates, each plate having two electrodes for electrical connection to two of the plurality of terminal busses. In one embodiment, by using five terminal busses pentagonally arranged around the plates, the surge protector requires only two types of plate/electrode configurations, thereby simplifying manufacture.

Abstract: The thin film, electrical device is an subminiature overvoltage circuit protection device in a surface mountable configuration for use in printed circuit board or thick film hybrid circuit technology. The surface mountable device (SMD) is designed to protect against electrostatic discharge (ESD) damage to electronic components. The circuit protection device comprises three material subassemblies. The first subassembly generally includes a substrate carrier, electrodes, and terminal pads for connecting the protection device 60 to a PC board. The second subassembly includes a voltage variable polymer material with nonlinear resistance characteristics, and the third subassembly includes a cover coat for protecting other elements of the circuit protection device.

Abstract: Surge suppressor apparatus comprising AC power line overvoltage protection, telephone voice line overvoltage and overcurrent protection, high speed data line overvoltage and overcurrent protection and coaxial transmission line overvoltage protection, all tied to a common ground.

Abstract: An output driver device (10) includes a first output transistor (12) and a second output transistor (14) coupled to a bias transistor (16). The bias transistor (16) is coupled to a ground potential. The first output transistor (12) is coupled to a first output pad (18) and the second output transistor (14) is coupled to a second output pad (20). The output driver device (10) has a direct non-metal path to ground potential from either the first output pad (18) or the second output pad (20). In this manner, an electrostatic discharge device on either the first output pad (18) or the second output pad (20) can be absorbed through the first output transistor (12) or the second output transistor (14), respectively, and through the bias transistor (16) without damaging the output driver device (10).

Abstract: A method for determining the extent of a transient's ability to cause MOV over heating and subsequent explosion by microprocessor analysis of an AC voltage input waveform with respect to a stored perfect sine wave. The microprocessor also calculates the RMS value of the applied voltage waveform and compares it to stored limits to determine if it could cause over heating of the MOV. In either case, the microprocessor will generate an out-of-range signal to a disconnect device to take the MOV, and also the load, if desired, off line until normal line voltage is restored.

Abstract: The present invention relates to a polymer fuse apparatus that provides bypass fuse protection. A polymer bypass fuse is comprised of an electrical conductor wherein a portion of the conductor is surrounded by an internal electrode, which is then surrounded by a layer of polymeric positive temperature coefficient (PTC) material, which is then surrounded by a conductive material similar to that of the internal electrode.Various hybrid combinations are also contemplated where in-line and/or bypass fuses are combined with other circuit components. One example is, a plurality of in-line and bypass fuses combined with a differential and common mode filter, which itself consists of a plurality of common ground conductive plates maintaining first and second electrode plates between the various conductive plates, all of which are surrounded by a material having predetermined electrical characteristics to provide fail safe filter and circuit protection.

Abstract: A gas-insulated semiconductor valve for high voltage power has an elongated valve stack with a plurality of semiconductor elements. The valve stack is provided with electrostatic shields for reducing the stresses on the insulating medium. The shields comprise a plurality of annular shields distributed along the longitudinal axis of the valve stack. The shields are arranged in planes which are substantially perpendicular to the longitudinal axis of the stack and surround the valve stack. The curved part of each shield has a substantially constant radius of curvature.

Abstract: An apparatus and method for protecting hardware devices using a spiral inductor. The surge suppressor protects hardware devices from electric surges by isolating the radio frequency from an inner conductor. The surge suppressor includes a housing, an inner conductor, a surge blocking device, and a spiral inductor. The surge blocking device is inserted in series with the hardware devices for blocking the flow of electrical energy therethrough. The spiral inductor is coupled to the surge blocking device and is shunted to ground for discharging the electrical surge.

Abstract: The surface mountable electrical device provides utilizes polymer composite materials to protect electronic components against electrical overstress transients. The device includes a first substrate having an electrode formed thereon. A portion of the electrode forms an electrical connector which projects outwardly from the substrate. A second substrate has a electrode formed on a surface thereof. A portion of the electrode on the second substrate forms a well or cavity. A voltage variable material is disposed within the cavity formed in the electrode on the second substrate. The two substrates are laminated together such that the electrical connector extends into the voltage variable material disposed within the cavity. Outer terminations adapted to be connected to an electrical circuit are formed on the outer surfaces of the substrates and are electrically connected to each respective electrode.

Abstract: In one embodiment, a variably conductive shunt is provided for protecting a read/write sensor element, e.g., an MR read element, which has first and second terminals. A variably conductive member is electrically connected between the first and second terminals. The variably conductive member conducts charge when a potential sufficient to damage the element is applied across the first and second terminals thereby protecting the element from the charge.

Abstract: A transient voltage surge suppression system incorporating a current protection device comprised of a voltage sensitive and a thermal sensitive device. The voltage sensitive device has a predetermined voltage rating and increases in temperature as voltage applied thereto exceeds its voltage rating. The thermal sensitive device is responsive to heating of the voltage sensitive device to break an electrical current path if an overvoltage condition sensed by the voltage sensitive device exceeds the voltage rating of the voltage sensitive device.

Abstract: A power switching apparatus is disclosed which has an electrical conductor to which high voltage can be applied. A series of circuits formed by a switching point and a current-limiting element which contains PTC thermistors and varistors is arranged in the cable run of the electrical conductor. An apparatus for operating the switching point interacts with the current-limiting element. The current-limiting element has n (where n is a natural number greater than 1) series-connected parallel circuits each having at least one PTC thermistor and at least one varistor connected in parallel with it. A current sensor arranged in the cable run of the electrical conductor or those connections of one of the PTC thermistors and of the varistor connected in parallel with it which are interconnected at two junction points in one of the parallel circuits are operatively connected to the input of the operating apparatus.

Abstract: An overvoltage protection device includes a first electrode member having a first substantially planar contact surface and a second electrode member having a second substantially planar contact surface facing the first contact surface. A wafer formed of varistor material and having first and second opposed, substantially planar wafer surfaces is positioned between the first and second contact surfaces with the first and second wafer surfaces engaging the first and second contact surfaces, respectively. The contact surfaces may apply a load to the wafer surfaces. Preferably, the electrode members have a combined thermal mass which is substantially greater than a thermal mass of the wafer. The wafer may be formed by slicing a rod of varistor material. The device may include a housing including the first substantially planar contact surface and a sidewall, the housing defining a cavity within which the second electrode is disposed.

Abstract: A surge arrester protection system includes a surge arrester, a first mechanism fixed on a first end of the surge arrester for directing arcs around the surge arrester and a second mechanism fixed on a second end of the surge arrester for directing arcs around the surge arrester. The first and second mechanisms each include a plurality of slots extending substantially radially therein. Additionally, a cap which covers a lower end of the arrester is used to catch material dripping from the surge arrester and a cap covering an upper end of the arrester is used to protect the arrester from animals and the elements.

Abstract: An electrical device has a housing with an internal cavity lined with insulating material. An electrical component is mounted in the cavity between the opposite ends of the housing. An electrically conductive probe is mounted in the cavity at one housing end. An end connector is mounted in the cavity at another housing end. The electrical component is electrically connected to the end connector and to the probe. The electrical component connection to the probe includes wedge insert engaging the component inner end and engaging an inner surface of the lining of insulating material to form a seal between them. Gas generated by the electrical component will not flow past the wedge insert in the direction of the probe.

Abstract: An electrical surge arrester comprises a stack of varistors (10) separated by conductive spacers (12), the respective faces of the varistors and the spacers being bonded for electrical and physical contact, and the outer surfaces of the stack having an insulating coating (14). The varistors have different cross-sectional size from the spacers, the elements of larger size thereby providing the `sheds` of the arrester.

Abstract: A surge arrester module having an array of MOV's and other components includes an insulative coating (16) for applying an axially compressive force to the stacked array. The component stack (20), while held in an axially compressed condition, receives the insulative casing that includes thermosetting resin that, when cured, has a coefficient of thermal expansion that is greater than that of the components of the stack. The coated stack is then cured at a temperature that exceeds the maximum expected temperature that will be experienced by the arrester components. Upon cooling, the components of the array are held in compression and adequate electrical contact with each other is maintained by the casing. Fiberglass strands (24, 28) are included in the casing for reinforcement and cantilever strength. A method of manufacturing the module is also disclosed.

Abstract: A telecommunications network (10) includes a main distribution frame (12) that receives telecommunications traffic carried over individual tip and ring signal line pairs (20) from trunks (18). The main distribution frame (12) provides the individual tip and ring signal line pairs (20) to a protector block (14). The protector block (14) includes a connector (22) for each individual tip and ring signal line pair (20). The connector (22) has a first terminal (24) that provides external access to low frequency voice band telecommunications traffic for POTS providers. The connector (22) has a second terminal (26) that provides external access to high frequency telecommunications traffic, such as ADSL for ADSL providers. The external access capability allows for the unbundling of physical connections at the main distribution frame (12) in order to provide competitive access to subscribers.

Abstract: In this invention, a whole-chip ESD protection scheme with the SCR string or the SCR/diode-mixed string are proposed to protect the mixed-voltage CMOS IC's against the ESD damage. The SCR string or the SCR/diode-mixed string is placed between the separated power lines. The ESD current is arranged to be discharged through the SCR string or the SCR/diode-mixed string and the ESD clamps between the power lines. Therefore, the internal circuits and the interface circuits between the circuits with different power supplies can be prevented from ESD damages. The number of the SCR's or the diodes in the SCR string or the SCR/diode-mixed string connected between the different power lines is dependent on the voltage difference between the different power supplies in the mixed-voltage CMOS IC's. When the IC is in the normal operating conditions, such SCR string or the SCR/diode-mixed string between the different power lines is kept off to maintain the independence of the power supplies in the mixed-voltage COMS IC.

Abstract: An electrostatic discharge protection circuit is used to protect an internal circuit that is electrically connected to an integrated circuit pad. The electrostatic discharge protection circuit comprises an erasable programmable read only memory, a capacitor, and a load element. The erasable programmable read only memory is provided with one source/drain connected to the pad, another source/drain connected to a power node, and a control gate. The capacitor is connected between the control gate and the pad while the load element is connected between the control gate and the power node. When electrostatic discharge stress occurs to the pad, the erasable programmable read only memory enters breakdown and is programmed by means of coupling effect through the capacitor. Under normal operation, the erasable read only memory is turned off via the load element.

Abstract: The current-limiting resistor has two connection electrodes (1, 2) which are arranged parallel to one another, a resistance body (3) which has PTC behavior and with which large-area contact is made by the connection electrodes (1, 2) and at least one varistor (4) which is in electrically conductive contact with the resistance body (3). The varistor (4) is of pillar-shaped design and has at least two first portions (4a) routed predominantly perpendicularly to the varistor axis and, arranged between said portions, a second portion (4b) having a reduced cross section compared with each of the first portions (4a). The material of the resistance body (3) fills an interspace (6), which is formed by the at least two first portions (4a) and the second portion (4b), and encloses the outwardly pointing edges (4c) of the at least two portions.This resistor can be operated at high voltages, for example 5 or 10 kV, and advantageously has a single resistance body 3 and a single varistor.

Abstract: A failure indicator device for a surge arrester (2) employs a conventional explosive disconnector (10). Operation of the disconnector (10) due to earth fault current passing through the arrester (2) causes an arc to be formed. Movement of the disconnector (10) away from the arrester (2) is guided and limited by a support arrangement (18, 20) that subsequently provides a solid and permanent conductive path to earth (6) from the arrester terminal (12), thus extinguishing the arc.