Abstract: An electric coupling device for connecting, disconnecting or limiting the current in an electric circuit. The electric coupling device includes a variable resistor. This resistance is variable between a very low value corresponding to a conducting state and a very high value corresponding to a substantially insulating state. Switching between the states takes place continually and in a very short time. The invention relates to an electric circuit provided with such an electric coupling device and a method performed in accordance with the function of the electric coupling device.

Abstract: An electrical circuit interrupter includes a primary or normal current carrying path and a transient or alternative current carrying path. The normal current carrying path is established by a movable spanner extending between stationary contacts during normal operation. The transient current carrying path includes at least one variable resistance element which transitions from a lower resistance to a higher resistance during interruption. The transient current carrying path forms an open circuit in parallel with the normal current carrying path during normal operation. Upon interruption, the transient current carrying path is favored for the fault current, completely interrupting the normal current carrying path. The variable resistance elements increase their resistivity during this phase of operation to aid in providing high levels of back-EMF for complete interruption of fault current through the device and limitation of let-through energy.

Abstract: A protective circuit for an electronic unit (EU) for protection against persistent overvoltage in an automobile, located between the network connections (DCIN, GND1) of an on-board voltage network with an on-board voltage (VB), and the operating voltage connections (DCOUT, GND2) of the electronic unit (EU). The protective circuit comprises an overvoltage indicator (OVI) which is connected to the network connections (DCIN, GND1) of the on-board voltage network, and triggers a switching signal (SO) when a threshold value of the on-board voltage (VB) has been exceeded, a switch (SW) with input electrodes (S, G) which can be activated by the switching signal (SO), and a voltage limiter (VL) to limit short-term overvoltage.

Abstract: The protection circuit (30) comprises at least one switch (FET1, FET2) comprising at least one control means (G1, G2) for adjusting the conductivity of said at least one switch (FET1, FET2). The conductivity is arranged to be adjustable by means of an electrical control conducted to the control means (G1, G2).

Abstract: There is provided an input/output device having of not exerting any adverse influence on other expansion devices connected to a system bus at the time of insertion or removal. An expansion device 800 comprises an electronic circuit 400 and a MOS switch 300, and is connected to a system bus (BUS) via a connector having long and short pins. The expansion device 800 two power supply systems, namely a stable power supply 250 and an unstable power supply 260. At the time of insertion or removal of the expansion device 800, power is provided to the MOS switch 300 and a high impedance maintaining circuit from the stable power supply via a pair of long pins, so as to reliably place the MOS switch 300 in a high impedance state, inside the expansion device the high impedance maintaining circuit 350 drives an open/close control terminal, and power is provided to the electronic circuit 400 from the unstable power supply 260.

Abstract: A power input protection circuit for an electrical device including a pass device having a full-conduction state, an off state, and a current regulation state, a control device coupled to the pass device for signaling the pass device to operate in one of the full-conduction, off or current regulation states, a high-voltage sensing circuit coupled to the control device for signaling the presence of an over-voltage condition to the control device, a high-current sensing circuit coupled to the control device for signaling the presence of an over-current condition to the control device, and an energy storage circuit coupled to the regulator and for supplying energy to the regulator when the pass device is in the off state is disclosed.

Abstract: A hot-line inserting and removing apparatus is capable of inserting and removing a circuit unit while the apparatus is in operation. An overcurrent protection circuit is inserted in a power supply in the hot-line inserting and removing apparatus, and has a switch which changes its resistance to prevent a rush current from flowing into a capacitive component of a connected load for protection against an overcurrent at the time the circuit unit is inserted.

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 circuit for detecting and automatically responding to ground faults. A passive protection PTC resistor is coupled in series with an active protection switch, the active protection switch being controlled by a control circuit to open the switch when excess current is detected to be flowing in the common path of one of the channels. Floating and grounded versions are described.

Abstract: A fault protective device (48) for limiting the maximum current and voltage applicable to electronic components and wiring (26, 30) located in the fuel tank (10) of an aircraft. Particularly, a fuel gauging system circuit (18) extends from a generator (20) located outside the tank to at least one probe (14) located in the tank and from the probe to instrumentation (24) outside the tank. The device is electrically coupled to the circuit at the tank wall (28) and includes a voltage clamp (50) and series inductor-capacitor resonant circuit (46), so that the resonant circuit provides a low series impedance when applied with a signal at the operating frequency of the input signal applied by the generator but provides a high series impedance when experiencing a signal of a different frequency indicative of a system fault.

Abstract: An electric coil includes bifilar pancake coils electrically connected to an adjacent pancake coil so that current flowing in adjacent turns of adjacent pancake coils flows in opposite directions at all radial region of the coil assembly. The superconducting fault current limiter is configured to provide a minimized inductance and low resistance in a normal state of operation. On the other hand, when a fault current exceeds a predetermined threshold, the resistance increases to a level sufficient for limiting the flow of fault current to a desired level until a circuit breaker connected within the electrical system opens the circuit.

Abstract: In an over current protection circuit of a semiconductor switching device, a change in a main current of a semiconductor switching device with respect to a change in the detected voltage of the resistor for current detection connected to the current detection terminal of the semiconductor switching device becomes gentle in the vicinity of a location where the semiconductor switching device is turned off. With the provision of the current protection circuit, the variation in the cut-off level of the over current with respect to the variation in the detected voltage of the resistor for current detection connected to the current detection terminal of the semiconductor switching device is suppressed so that the semiconductor switching device can be protected from being breakdown due to the over current flow.

Abstract: An internal power protection device which prevents the flow of power to an electronic component in response to an over-voltage or under-voltage signal condition. When the power supplied to the component is within a normal safe operating range for components of that type, the device allows power to flow through it to the power input terminal of the component. When the power supplied to the component is outside the normal safe operating range for components of that type, the device prevents power from flowing to the power input terminal of the component.

Abstract: A current limiter is provided to protect a fieldbus network from electrical shorts in the wiring of the spur cables and network devices attached to the spur cables. In the event of an electrical short, the impedance of the current limiter and the spur connection increases permitting the remainder of the network to continue to function. To facilitate repairs, the current limiter includes an indicator that signals excessive current in the spur. A method of connecting a spur cable to the network is provided where the spur cable is connected to a separate current limiter module that is pugged into a connector block.

Abstract: A power line filter connected to single-phase power lines (110-230 VAC, 50-60 Hz) enables transmission of HomePNA-type home network signals between network nodes connected to the main power lines as a network medium. The filter includes fuse resistors (R1, R2) that limit the current from the main power line, a transit diode circuit that clamps the bolts to a prescribed limit, eliminating energy that may be present in main power spikes. A pair of X2-type capacitors pass the 1 MHz or higher HomePNA signals, while rejecting the 50-60 Hz main power signal. A choke-type inductor eliminates any residual high voltage signals in the 50-60 Hz range by short circuiting the power signals, while maintaining a high impedance at the 1 MHz range, enabling the HomePNA signals to be safely passed to the RJ-11 connector of a physical layer transceiver of the Home Network Node.

Abstract: Proposed is a molecular arrangement comprising a movable molecule which is surrounded by a molecular cage-like arrangement fixed on a surface. The movable molecule is in a mobilized state in which it is decoupled from the cage-like arrangement. This means that it is out of registry with the van-der-Waals lattice of the molecular cage-like arrangement. The movable molecule is further decoupled from the surface in that it is not physisorbed or chemisorbed thereon. It shows an energy barrier for rotational movement equal or lower than kT.

Abstract: An object of the invention is to obtain a Zener zapping device which can reduce the time required for Zener-zapping and the scale of the 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: An overvoltage protection circuit is provided for protecting electrical equipment from transients on power lines (41, 42). The circuit has a string of series-connected silicon avalanche diodes (SADs) (40)connected across the power lines (41, 42) to provide an initial clamping threshold before energy-absorbing modules (43a, 43b, 43c) come on line to provide secondary clamping. The modules (43a, 43b, 43c) include a number of metal oxide varistors (MOVs) (44) connected in parallel and a switching device in the form of a gas arrester (45) connected in series with the MOVs (44). A resistance (46) is connected in parallel with the gas arrester (45) to form a high pass filter with the natural capacitance of the MOVs (44). This maintains the voltage across the resistance (46) well below the switch operating level during normal conditions and enables a component such as a 230 V fast acting gas arrester (45) to be used.

Abstract: An audio loudspeaker protection circuit used to protect single or multiple array connected audio transducers, and passive audio crossover networks from damage. An audio loudspeaker protection circuit providing protection during power overload, high speed transients, or direct current. This circuit has an adjustable activation control that accommodates broad power ratings for audio transducers, irrespective of the total load impedance. No sound coloration, dynamic range, or frequency response losses are added when implementing this circuit. This is due to high impedance, and low capacitance design. Virtually no power is consumed during normal audio system operation. The circuit is able to activate with any audio or non-audio signal, regardless of signal input polarity. The circuit comprises of several elements consisting of two high-speed rectifier circuits, a threshold detect circuit, a thyristor crowbar circuit, a relay, and a relay coil current regulator.

Abstract: An interface between a main computer 20 and a peripheral unit 30 allows connection/disconnection of the peripheral unit to and from the main computer during the operation of the main computer, while achieving reduction of fluctuation in the source voltage caused by hot line connection/disconnection, as well as a reduction of the circuit size. The interface includes a connector having long terminal pairs and short terminal pairs, by which the peripheral unit 30 is connected to the main computer 20. The peripheral unit 30 contains a delay circuit comprised of a FET 10 for controlling ON/OFF operation of the electric current path, a capacitor C1, and resistors R1 and R2. The signal path containing R1 and R2 forms a closed loop only when the peripheral unit is completely inserted into the main computer. During the insertion, the long terminal pairs are first connected, which is followed by connection of the short terminal pair.

Abstract: A sensing terminal and a receptacle are installed in a charge battery and a charger, respectively. During charging, a charging circuit within the charger will detect whether the battery is pulled out from the charger. If the battery is pulled out, the power source will be turned off in a very short time so that no voltage will be sent from the terminal of the charger in order to protect the charger. As the charge battery is pulled out from the charger, no spark is generated and the battery is prevented from being burned out.

Abstract: The present invention provides a two-terminal, transistor-PTC, circuit protection device that has a reduced size and weight and is particularly suitable for use, for example, in portable electronic devices and high density electronic circuits. According to one embodiment of the present invention, a circuit protection device comprises a positive coefficient temperature (PTC) element and a bipolar transistor having base, collector, and emitter terminals. The PTC element is connected between the base and collector terminals of the transistor. The PTC element may be thermally coupled to the transistor and packaged with the transistor as a hybrid device. An electrical load may be connected to the collector terminal of the transistor. According to another embodiment of the present invention, a circuit protection device comprises a PTC element and a Darlington circuit having base, collector and emitter terminals. The PTC element is connected between the base and collector terminals of the Darlington circuit.

Abstract: A computer has at least one adapter card slot for receiving an optional adapter card. A cover plate is rotatable hinged and has open and closed positions. In the closed position, the cover plate covers the adapter card slot and inhibits the insertion or removal of an adapter card. When the cover plate is raised into the open position, a tab on the back of the cover plate is rotated out of the slot of an optical switch, and the optical switch then signals circuitry to remove power and bus signals from the adapter card slot; thereby permitting the adapter card to be removed from or inserted into the slot without removing power to the entire computer. When the cover plate is returned to the closed position, the tab is reinserted into the slot of the optical switch, which in turn signals the circuitry to return power and bus signals to the adapter card slot.

Abstract: A circuit protection device for protecting an electrical load includes a three-terminal switch element such as a bipolar, or junction or metal-oxide-semiconductor field effect, transistor and a positive temperature compensation (PTC) resistor. In several embodiments the PTC resistor is in series with the current-carrying electrodes of the transistor. In other embodiments the PTC resistor, or a second PTC resistor, is connected to a control element of the transistor. Both DC and AC load-protection circuits are described.

Abstract: A device and method for providing overvoltage and overcurrent protection to equipment and personnel that come in contact with electrical lines, particularly telecommunications lines. The overvoltage protection is provided by connecting overvoltage protectors between conductors of the telecommunications line, or between each of the conductors and ground. The overcurrent protection is provided by solid-state bidirectional, resettable, fold-back type current limiters that limit maximum current flow at a predetermined level. These current limiters are arranged in line to the conductors of the telecommunications line and in series with equipment that are connected to the telecommunications line. The overvoltage protectors and the current limiters can be combined to form an integrated protection device, or they can be packaged as separate and distinct devices.

Abstract: For use with a power supply having first and second circuit protection devices, a detection circuit, a method of monitoring the protection devices and a power supply employing the circuit or the method. In one embodiment, the detection circuit includes (1) a bridge circuit coupled to the first and second circuit protection devices, (2) a resistor parallel-coupled across one of the first and second circuit protection devices and (3) a sensing circuit, coupled to the bridge circuit and the resistor, that senses an imbalance in the bridge circuit and develops therefrom a failure signal when at least one of the first and second circuit protection devices becomes inoperable.

Abstract: A two wire solid state AC/DC circuit breaker has a line terminal for connecting the power and the load terminal for connecting to a load. A pair of insulated gate bipolar transistors (IGBTs) are connected in parallel across the line and load terminals in reversed polarity relative to one another. A diode is placed in series with each IGBT limiting current flow to the direction of polarity of the IGBT. Current sensing circuitry is connected across the terminals for sensing current passing through the IGBTs and when a predetermined level has been exceeded, a voltage pulse is generated to the respective bases of the IGBTs to turn them off. This terminates current flow through the respective IGBTs instantaneously.

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 system interconnection device connected between two systems, such as a commercial bus line carrying power from a commercial power line and a private bus line carrying power from a private power generator, is able to connect and disconnect the two systems, and, in the event of a fault, has a current-limiting effect, thus preventing instantaneous voltage drop of the respective bus lines. In the system interconnection device, unit parallel circuits made up of diodes and DC reactors are serially connected so that the diodes thereof have opposite directions. With this structure, in realizing operations equivalent to those of a conventional system interconnection device having a DC reactor between DC terminals of a single-phase rectifying bridge circuit, the number of diodes, which are rectifying elements, can be halved.

Abstract: An electrostatic discharge protection circuit for integration into an integrated circuit device. The protection circuit includes at least one transistor having a first terminal connected to an input or output terminal of the integrated circuit device, a second terminal connected to a supply line for the integrated circuit device, and a control terminal connected to ground. In a preferred embodiment, the transistor is formed by a structure that includes a substrate of a first conductivity type, a first region of a second conductivity type, a second region of the first conductivity type, a third region of the first conductivity type, and a fourth region of the second conductivity type. The third region has greater conductivity than the substrate and the fourth region has greater conductivity than the first region.

Abstract: The present invention includes an aircraft fuel tank protective barrier which includes a transformer. The transformer has a first winding coupled to a fuel tank indicator through wiring which forms a threat side of the barrier, and has a second winding coupled to one or more sensors in a fuel tank which forms a protected side of the barrier. The transformer is operable to magnetically couple normal signals between the fuel tank indicator and the sensors in the fuel tank while limiting an amount of energy delivered to the fuel tank in the event of a fault experienced on the wiring.

Abstract: A laminar sensor for detecting changes on a laminar substrate. The sensor includes a laminar sheet which has a first surface and a second opposite surface, and is made from a conductive polymer composition which exhibits PTC behavior. A plurality of sensing elements are electrically connected in series on the sensor. Each sensing element is formed as an electrode pair containing a first electrode and a second electrode. The first and second electrodes may be on the same surface of the laminar sheet or on opposite surfaces of the sheet. Two electrical leads are present for connecting the sensing elements into a circuit, which may be used to detect changes in resistance which occur when a sensing element is exposed to an elevated temperature, a change in pressure, or a solvent.

Abstract: A fault current interrupter is provided by the parallel combination of a polymer current limiter and a voltage dependent resistor connected across a pair of separable contacts to permit the interruption of current without the occurrence of arcing between the contacts when the contacts first become separated. The polymer current limiter is selected to have a relatively low resistance at quiescent operating currents and a substantially higher resistance at short circuit overcurrents. This allows the current to transfer away from the contacts through the polymer current limiter until the voltage across the voltage dependent resistor causes the voltage dependent resistor to become conductive and thereby transfer the current away from the polymer current limiter.

Abstract: A two terminal circuit protection arrangement that: (1) is intended to be series connected in a line of the circuit; (2) comprises (a) a series switching transistor (1) that controls the line current, (b) a control transistor (4) that controls the base or gate voltage of the switching transistor and is responsive to an overcurrent through the switching transistor, and (c) a voltage source, for example a battery (3), a dc-dc converter (58/59) or a Seebeck device (43), applied to the base or gate of the switching transistor which biases the switching transistor into or toward conduction in normal operation; and (3) is capable of being remotely reset into a conducting state by stopping current in the line. The arrangement enables the initial voltage drop that is required to turn the switching transistor (1) on to be reduced or eliminated while requiring relatively little current from the voltage source. The arrangement can be reset remotely by briefly removing the voltage source or load from the circuit.

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: An electrostatic discharge (ESD) discharge circuit provides robust protection to an integrated circuit (13). In one embodiment, a resistive element (71) ensures that current shunting bipolar devices (60, 62, and 68) turn-on before devices within the integrated circuit are damaged by secondary breakdown. In another embodiment, a two terminal device (69) provides base current to a bipolar device (60) that shunts excess charge. This two terminal device enters gate aided junction breakdown as does an N-type MOSFET (72 and 74) but does not exhibit the same snap-back characteristics during ESD. Consequently, the two terminal device ensures that the ESD circuit tracks process modifications to the integrated circuit.

Abstract: The present invention includes integrated circuitry, an interface circuit of an integrated circuit device, cascode circuitry, method of protecting an integrated circuit, method of operating integrated circuitry, and method of operating cascode circuitry. One aspect of the present invention provides integrated circuitry including a driver adapted to couple with a pad and internal circuitry of an integrated circuit device, the driver includes a first transistor coupled with the pad; cascode circuitry including a second transistor coupled with the pad and a third transistor coupled with ground, the cascode circuitry configured to remain in an untriggered state during the presence of stress currents at the pad; and protection circuitry intermediate the pad and ground and configured to shunt stress currents from the pad to ground.

Abstract: An electrostatic discharge (ESD) protection circuit includes circuitry for providing protection against ESD events which occur either within an ESD pad ring (intra-ring) or between different ESD pad rings (inter-ring). Self-triggering voltage clamp circuits or back-to-back diode circuits can be used to properly interconnect the positive polarity rails and the negative polarity rails of the ESD pad rings. Self-triggering voltage clamp circuits are advantageous in that they provide improved ac signal isolation (i.e. reduced noise coupling between the ESD pad rings, and thus reduced noise coupling from the digital I/O pads to the analog I/O pads).

Abstract: An electrical device which includes a resistive element which exhibits PTC behavior, is composed of a conductive polymer composition, has a planar shape with first and second major surfaces, and has a thickness of at most 0.64 mm . The resistive element is sandwiched between first and second metal foil electrodes, at least one of which has a thickness of at least 0.055 mm, so that the ratio of the resistive element thickness to electrode thickness is 1:1 to 16:1. The device can be used as a circuit protection device in an electrical circuit.

Abstract: The present invention provides a protection circuit for, and method of, sensing a transient condition and limiting a current, and a power supply having a filter incorporating the protection circuit or method. In one embodiment, the protection circuit includes: (1) a current-limiting component coupled between the filter and a return node, (2) a bypass switch coupled across the current-limiting component, (3) a load-current return switch series-coupled between an output of the power supply and the return node and (4) a control circuit that senses a transient condition in the power supply and controls at least one of the bypass switch and the load-current return switch.

Abstract: A lead on chip (LOC) semiconductor device or a chip on lead (COL) semiconductor device with a protection circuit. Non-connection pins are made shorter than connection pins to reduce the inductance of the non-connection pins, or to obtain a different capability of the protection circuit for non-connection pins with respect to connection pins. The time constant of the protection circuit for the non-connection pins is made longer than that of the protection circuit for the connection pins. Further, the clamping capability for the connection pins is made greater than that for another connection pin adjacent to the connection pin.

Abstract: An electromagnetic safety (EMS) enhancement circuit is provided for a USB (Universal Serial Bus) system, which can simulate an unplugging and replugging action so as to ensure continuous operation of the USB device after being disconnected from the USB interface due to electromagnetic interferences. The EMS enhancement circuit utilizes an EMS detection unit to detect the EMS condition of the data communication between the USB device and the USB interface; if abnormal, the EMS detection unit will output an overflow signal to a resume-control unit.

Abstract: The present invention relates to a passive electronic component architecture employed in conjunction with various dielectric and combinations of dielectric materials to provide a differential and common mode filter 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, fusing and surge suppression, alone or in combination.

Abstract: The arrangement connects at least one module (M) to a power supply unit (SV) in an apparatus in such a way that a connection is provided when the power supply unit (SV) is switched on. In the apparatus is a contact element (KG, VE) which is located outside the module and has leading contacts and a device for current limitation (AS) of an initial current flow.

Abstract: A protective circuit for protecting a circuit from a destructive voltage or current, comprising a MIS transistor, and at least one resistor connected in series with the MIS transistor for limiting current flow through the MIS transistor, wherein a resistance value R of the at least one resistor connected in series with the MIS transistor satisfies the relation R>(A-B)/C, wherein A is a surge voltage against which protection is provided, B is a hold voltage at a breakdown of the MIS transistor, and C is a maximum allowable current of the MIS transistor. The at least one resistor is connected in series with a source of the MIS transistor, a drain of the MIS transistor, or both the source and the drain of the MIS transistor, and the resistance value of the resistance is preferably smallest value that satisfies the relation R>(A -B)/C.

Abstract: A voltage spike suppressor for polyphase systems including those with alternatively connectable polyphase sources, the suppressor having a diode bridge network connected to couple overvoltage transients exceeding the nominal line voltage by more than twice the forward drop of a diode in the bridge network to a capacitor and resistor network. In four-wire systems, a center-tap in the capacitor and resistor network can be connected to the neutral lead in the power circuit. Metal Oxide Varistors may be used to clamp the center-tap voltage in the capacitor-resistor network. A diode clamp circuit may be used to limit common-mode voltage transient swings in the capacitor-resistor network and in the neutral terminal when present.

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: A protective impedance for a mains voltage supplied electronic circuit has ohmic resistors which are applied to a substrate as film. At least two resistors form a series connection. At least two series connections are connected in parallel. This permits relatively large operating currents with relatively short series connections.

Abstract: A protection device for trench isolated technologies. The protection device includes a lateral SCR (100) that incorporates a triggering MOS transistor (120) with a first gate electrode (116) connected to the cathode (112) of the SCR (100). The anode (110) of the lateral SCR (100) is separated from the nearest source/drain region (122) of the triggering MOS transistor (120) by a second gate electrode (132) rather than by trench isolation. By using the second gate electrode (132) for isolation instead of trench isolation, the surface conduction of the lateral SCR (100) in unimpeded.