Abstract: A signaling system employing indicator lamp means and an audible alarm is employed to remind a user to periodically test his GFCIs and to provide information regarding the status of the GFCI. The power lines that supply the GFCI with power are also coupled to the circuits on the PCB to disconnect power to those circuits of the GFCI that trips due to faults or tests.

Abstract: A connector that is particularly suitable for use in high speed data transmission is provided in the form of a plug connector that may be terminated to the end of a high speed cable. The connector has a plurality of terminals for terminating to respective signal wires, ground wires and power wires of the cable, and also has an additional terminal that serves to detect and identify status information about the cable to circuits on a circuit board to which the cable is connected thorough the plug connector and a mating receptacle connector. This detection terminal is shorted to another terminal of the connector, preferably a power ground, or return, terminal. The shorting is done with an electronic component that modifies the voltage passing from the shorted terminal through the detection terminal. The modified voltage may be easily read on the circuit board to determine the status of the cable (such as the speed of the cable) or an electronic device attached thereto.

Abstract: A power supply circuit detects ground fault paths, and miswiring of the load, using a test mode in which electrical power is applied to only one power output terminal of the power supply relative to the ground terminal, while substantially no electrical power is applied to the second power output terminal relative to the ground terminal. If application of power during the test mode causes substantial current flow through ground, then there is a ground fault path, or an incorrect connection between the midpoint of the load and ground. The power supply further includes unique features for signaling the presence and kind of fault it has detected; the power supply is capable of distinguishing between ground faults in at least two different locations, and when a fault is detected, the power supply signals the presence of the fault and its location, e.g., by timed blinking of the connected discharge light. These features are enhanced by a diagnostic analyzer for connection to the power supply.

Abstract: A switch status monitoring system (10) includes a switch signal processor (16) that operates in either of a supervised mode or an unsupervised mode for each monitored switch (12). Selection of the operating mode is made via configuration data provided to the switch signal processor, for example, from an applications processor (20). In this manner, reconfiguration of the mode of monitoring, supervised or unsupervised, of any particular switch within a system is accomplished by providing revised configuration data and without changes or modifications to the switch signal processor hardware. As will be appreciated, the present invention has application in for example door or window monitoring systems and in other similar security system applications.

Abstract: A method for identifying short circuits in a low-voltage network includes the step of determining a first envelope and a second envelope for a plurality of locus curves of a current steepness as a function of a current in a low voltage network, the first and second envelopes including all switching angles, the first envelope being determined for a lower power factor, the second envelope being determined for an upper power factor. Additionally a third envelope is determined taking into account rated-current switching operations between the lower power factor and the upper power factor. A resultant envelope is formed from a combination of the first, second, and third envelopes by overlaying the first, second, and third envelopes. The resultant envelope defines a tolerant locus curve criterion indicating a short circuit for values outside the tolerant locus curve criterion. A configuration for identifying short circuits is also provided.

Abstract: A circuit and device to detect grounding problems in electrical soldering irons. The device includes a cleaning sponge in electrical connection with a sensor element. The sensor element is connected to the controlling circuitry which is in turn connected to a safety grounding point, such as a screw of a face plate of an electrical outlet. The circuitry includes LED's which indicate when the grounding mechanism is functional, and when the grounding connection is broken. Additional circuitry tests for a low impedance path to ground via a sensor element contacted by the soldering iron tip or (in the case of an isolated tip) the soldering iron heater barrel. Further circuits indicate when the cleaning sponge has gone dry, and when the operator has an unsafe level of electrostatic charge.

Abstract: This invention relates generally to monitoring systems and more particularly concerns devices and systems used to monitor bed patients in hospital or other care-giving environments. In accordance with a first aspect of the instant invention, there is provided a binary switch-type device (e.g., a “mat”) for use in patient monitoring situations which contains, in addition to a conventional patient detection circuit, identification circuitry that can be sensed by an attached electronic monitor. The identification circuitry can be sensed by the electronic monitor and is designed to be configured to serve many different purposes, including, by way of example only, identification of the type of mat attached thereto, detection of connectivity problems, tracking mat usage time, and identifying mats that are nearing the end of their useful lives.

Abstract: The electronic trip device comprises a processing unit comprising protection means, and an initialization device of said processing unit. The initialization device comprises means for initialization after an interruption comprising at least one storage register connected to the protection means to store a value of at least one quantity of a protection function and to supply a value of said at least one quantity when initialization of the processing unit is performed. A back-up power supply circuit supplies the storage register, and means for monitoring the back-up power supply circuit delete the register values when a voltage of the back-up power supply circuit drops below a preset threshold.

Abstract: A ground fault location system is used in a multi-phase ungrounded or high-impedance grounded power network. A signal generator is coupled to the network at a first location and generates for each network phase an individual non-DC voltage signal between such phase and ground. A ground fault detector is coupled to the network at a second location and has a summing device and an annunciator. The summing device is coupled to all of the phases of the network at such second location, sums any current passing therethrough, and produces a sum signal. The annunciator receives the sum signal and provides an indication when such signal is non-zero. Each phase of the network at the second location has a distribution current passing therethrough, the sum thereof normally being substantially zero and resulting in a substantially zero sum signal and the lack of an indication from the annunciator based on such distribution currents.

Abstract: A system for warning regarding the presence of manually attached grounding contacts (21) on high voltage conductors (3), comprises a) a naked additional conductor (1) close to the high voltage conductor (3), however spaced therefrom, and with an ability to be clamped resiliently to contact with the high voltage conductor (3) when the grounding contact (21) is attached; and b) a warning device (20) having connection means (4, 5) to the high voltage conductor (3) and to the additional conductor (1). The warning device has, in a part (24) arranged near the high voltage conductor (3), equipment for sensing whether the additional conductor (1) has been brought to contact with the high voltage conductor or not, and for transmitting a signal regarding this condition to another part (26) of the warning device which is remote from the high voltage conductor, preferably at ground potential. From this part (26) the signal can be transmitted to an operation central.

Abstract: A multiplexing apparatus multiplexes between processing units and a battery unit of a vehicle which are connected to one another by wire harnesses, by grouping a variety of on-board controlled objects into a plurality of neighboring controlled objects and controlling each of respective processing units. The wire harness has electric conductors of which the outer peripheral portion are covered with a first insulating layer, electric conductivity layer which covers the electric conductors, a second insulating the peripheral portion of the electric layer which covers conductivity layer, means for applying an electric potential to said electric conductivity layer, and means for monitoring the electric potential of said electric conductivity layer.

Abstract: Electrical consumers receive load current from a supply voltage via two or more power switches. A false-closure detection device includes a measuring device and a diagnostic device for the detection of faults. The measuring device is connected parallel to the power switches and the electrical consumer lying in series with the switches. A diagnostic voltage is compared as the output signal of the measuring device with a reference value for the detection of false closures in the load circuit.

Abstract: The present invention provides an alarm apparatus suitable for use with an object or person, which apparatus is activated upon energisation of the object or person, wherein said alarm apparatus comprises a power source, at least one alarm means, actuating means associated with an unearthed sensor which actuates said alarm means in the event of the energisation of said object or person.

Abstract: A ground fault circuit interrupter (GFCI) with built in intelligence is described that includes circuitry to automatically indicate a device miswiring condition. When a GFCI is wired with its AC and LOAD terminals reversed, downstream devices are still protected in the event of a ground fault but the duplex receptacle on the GFCI itself is not. The invention incorporates miswiring sense circuitry that automatically triggers the generation of visual and audible alarms in the event a miswiring condition is sensed. The invention employs an alarm inhibiting technique that incorporates sense circuitry connected to the AC terminals on one side of the internal GFCI switches or relays and alarm generation circuitry connected to the LOAD terminals on the opposite side.

Abstract: An improved circuit and method for connecting a device to an actuator-sensor interface (“ASI”) bus. The circuit provides the proper AC and DC coupling between the device and bus during normal operation, while providing AC and DC decoupling in the event of a short circuit or when the device is disconnected. The circuit accomplishes these goals while advantageously eliminating some of the components used in prior art circuits.

Abstract: A circuit arrangement for monitoring leakage currents of a circuit which includes a plurality of valve coils connected in parallel to a supply line and adapted to be connected to ground by way of individual switches, and wherein the supply line is connected by way of a main switch to the positive pole of the supply voltage source and, further, to a testing current source used as a test signal source, is designed such that prior to each closing of the main switch, with the individual switches still open, the testing current source is connected to the supply voltage source and thereby activated. The result is an increase of the voltage potential on the supply line. A comparator establishes the difference between the potentials on the supply line and the supply voltage. If the difference exceeds a threshold value, this indicates leakage current.

Abstract: A method and apparatus for detecting silent faults in feeding diodes of redundant DC power supplies. The voltages on both sides of the feeding diodes are measured. Arrangements are then made to ensure that if corresponding feeding diodes are both operative, that current flows through a particular one of these diodes. The measurements of voltage under the various conditions will reveal any open or shorted feeding diodes. The voltage across a diode can be altered by heating the diode through the process of heating a power resistor that is in thermal contact with that diode. Alternatively, a controllable rectifier of a power source can be controlled to reduce the voltage of that power source, and thereby drive current through the diode connected to the other power source. Advantageously, this arrangement allows silent faults in these diodes to be detected without substantial risk of causing the failure in the powered system.

Abstract: A pulse width modulation driver provides programmable current control for a variety of load current ranges using a modulation feedback block. The block scales a signal representative of a sensed current flowing through the load by a selectable gain multiplier. The scaled signal is compared to a target current value to indicate to a driver control when to generate trigger signals for switching current through the load. In this way, load currents can be amplified to match the operational range of the comparator.

Abstract: A resistance tester is incorporated into a grounding device. The resistance tester includes a test circuit, a battery, a switch and a set of indicator devices. With the grounding device being worn and the cord end of the device in contact with the user so as to form a closed circuit, the test circuit measures the resistance level of the grounding device upon activation of the switch. The indicator devices provide a visual indication of the resistance level, i.e., too high, too low or within acceptable limits. The resistance tester is self-contained and may be used anytime by the user to ensure that the resistance of the grounding device is acceptable.

Abstract: The present invention provides a remote detection device including a conventional measurement device, such as a thermostat, having an internal contact which is wired in series with a resistor and two wires of a standard telephone line. When the measurement device reaches or surpasses a predetermined set value, such as a predetermined temperature, the measurement device will close the internal contact such that the resistor will short the telephone line. Accordingly, the owner or manager of a building will receive a busy signal when dialing the telephone line connected to the remote detection device. The device, therefore, allows the building owner or manager to check on the condition of the building at any time. The device is not susceptible to breakdown or malfunction due to its simplicity. Moreover, the device is not susceptible to shutdown because the device is passive and does not require connection to a power source for operation.

Abstract: A controller for a starter/generator used with an aircraft engine, includes means for monitoring field return current in a generator field winding; means for monitoring generator voltage; and microprocessor control means for adjusting generator field current as a function of the field current and voltage and field return current. The field return current and output voltage monitoring functions allow for open field, field integrity, over voltage, field weakening and torque limiting functions to be realized in an integrated programmable system configuration.

Abstract: A load short-circuit failure detection apparatus comprises load current drive means 8, load current control means 7, load current detection means 6 and load short-circuit failure judging means 9 and judges that a short-circuit failure occurs in a load when a state in which a load current detection value exceeds a predetermined value within a first predetermined time continues for a second predetermined time so that the load drive means can be protected, a short-circuit failure of the load can be detected, and the erroneous detection of a short-circuit failure caused by a transient overcurrent can be prevented.

Abstract: A fuse protected power supply circuit for a sensor-operated solenoid controls plumbing fixtures such as automatically-operated faucets, automatically-operated flush valves, hand dryers, soap dispensers and the like. The circuit includes two automatically resettable fuses, one to protect the power supply circuit if the AC-operated solenoid should short and a second to protect the power supply circuit in the event that the sensor which detects the presence of a user of the plumbing device should short. The automatically resettable fuses provide a simple and reliable troubleshooting method in that replacement of either the sensor or the solenoid, depending upon whether one or both are in a shorted condition, allows the circuit to return to normal operation. Such troubleshooting may be undertaken by a maintenance person without the need of sophisticated electronic meters or similar troubleshooting devices.

Abstract: A diagnostic system for detecting when one or more temperature sensors as found in motor vehicle climate control systems are invalid. The system works at extreme temperature conditions and functions to distinguish between sensor faults such as open or short circuits and true sensor temperature readings, which could be, misinterpreted as faulty readings. In particular, combinations of ambient temperature sensors, in-car-temperature sensors and evaporator air temperature sensors are tested by the diagnostic algorithm to make such determinations.

Abstract: A portable tester plugs into a receptacle in a branch circuit of an electric power distribution system to verify protection against arc faults, line to ground faults and neutral to ground faults provided by a circuit breaker located at a remote load center or by ground fault and, or arc fault interrupters in the receptacle, and also checks for proper wiring. The arc fault detector gates phased back rectified half cycles of the ac power to generate step changes in the instantaneous amplitude of current in the branch circuit which mimic the repetitive striking of an arc. Preferably, only half cycles at least 60 ms apart are gated so that the user can verify the time to trip with a watch and can count the gated half cycles to trip by counting pulses generated by a light emitting diode (LED) in the gating circuit.

Abstract: An apparatus and method for distributing power includes a housing, at least one input terminal, and at least one output terminal. The input and output terminals are each positioned in the housing. The input terminal is operatively connected to the output terminal. At least one circuit breaker is positioned in the housing. The circuit breaker includes an on position and an off position. The circuit breaker is operatively connected to the input terminal and the output terminal. An alarm circuit is operatively connected to the output terminal to prevent an alarm signal when an electronic chassis is not operatively connected to the output terminal and the circuit breaker is in the off position.

Abstract: In order to detect abnormality of a cable, the cable has an electrical conduction line surrounding a power supply line, an electric potential of the electrical conduction line is controlled by a controller, and the abnormality of the cable is judged by detecting the inability of the controller not to control the electric potential of the electrical conduction line in case of contact by the electrical conduction line with the ground or the power supply line. Damage to the power supply line from the accident is prevented by previously detecting the accident of the cable, thereby, the reliability of the cable is highly improved.

Abstract: A power supply circuit detects ground fault paths, and miswiring of the load, using a test mode in which electrical power is applied to only one power output terminal of the power supply relative to the ground terminal, while substantially no electrical power is applied to the second power output terminal relative to the ground terminal. If application of power during the test mode causes substantial current flow through ground, then there is a ground fault path, or an incorrect connection between the midpoint of the load and ground. The power supply further includes unique features for signaling the presence and kind of fault it has detected; the power supply is capable of distinguishing between ground faults in at least two different locations, and when a fault is detected, the power supply signals the presence of the fault and its location, e.g., by timed blinking of the connected discharge light. These features are enhanced by a diagnostic analyzer for connection to the power supply.

Abstract: A multiplexing apparatus multiplexes between processing units and a battery unit of a vehicle which are connected to one another by wire harnesses, by grouping a variety of on-board controlled objects into a plurality of neighboring controlled objects and controlling each of respective processing units. The wire harness has electric conductors of which the outer peripheral portion are covered with a first insulating layer, an electric conductivity layer which covers the electric conductors, a second insulating the peripheral portion of the electric layer which covers conductivity layer, a circuit for applying an electric potential to the electric conductivity layer, and a monitor for the electric potential of the electric conductivity layer.

Abstract: A fault indicator for detecting the occurrence of a fault current in a monitored conductor includes a rotatably mounted indicator flag. The flag is positioned in either a reset indicating or a fault indicating state by a magnetic pole piece, which is magnetized in one magnetic direction or the other by momentary application of a current in one direction or the other to an actuator winding on the pole piece. An auxiliary magnetic circuit comprising an auxiliary pole piece magnetized by the actuator winding, a reed switch and a bias magnet magnetically aligned to oppose the reset magnetic orientation and reenforce the trip magnetic orientation of the magnetic pole piece provides contact closure upon occurrence of the fault current.

Abstract: A sound warning circuit for PCI hot plug basically comprises: a timer that takes as inputs a fixed frequency clock and the system port B's bit 0, and which controls the system; a logic AND gate that takes as inputs the timer output and the system port B's bit 1; a speaker driver that takes as an input the AND gate's output; and a speaker that operates based on the speaker driver. In a further embodiment, the timer takes as inputs a fixed frequency clock and either the system port B's bit 0 or a PCI card VDD input, while the AND gate takes as inputs the timer output and any one or more of the system port B's bit 1, a chassis ground cable 0 input, and a chassis ground cable 1 input. In a further embodiment, the AND gate takes as inputs the timer output and either the system port B's bit 1 input or the output of a D Flip-Flop, the latter having the chassis ground cable signal as an input and receiving a reset signal from an AND gate, the latter having as inputs a reset switch input and a system reset # input.

Abstract: A method and system for detecting faults with a self-exciting sensor includes a monitor circuit coupled to the self-exciting sensor for monitoring a signal associated with the sensor and generating a failure signal. A voltage limiting circuit is coupled to a receiver circuit associated with the self-exciting sensor for generating a first output signal within a valid range of operation in the absence of the failure signal. The voltage limiting circuit also generates a second output signal outside the valid range of operation in response to the failure signal so as to eliminate the necessity of an additional input to control logic associated with the self-exciting sensor.

Abstract: A device for detecting low magnitude electrical currents includes a generally toroidally-shaped member made of magnetic material that provides an air gap, and a magneto-resistive device in the form of a bridge located in the air gap for sensing a current flowing through a conductor that passes through the member. In order to reduce damage due to overcurrents, the member has a portion of reduced cross-sectional area to cause saturation of the member. The device can be used in an earth leakage current detector.

Abstract: A fail-safe fluid transfer control apparatus has full redundancy in the response to various inputs such as overfill probe signals, ground detection signals, and the like. Independent microprocessor controllers independently evaluate the inputs and each output control signals to close a respective relay when the inputs indicate that fluid transfer may commence. The relays are arranged in series such that both must be closed for a fluid transfer to commence. The control signals from each controller include a static signal and an alternating signal, both of which must be properly output to close its respective relay. Each controller monitors the state of each relay, and discontinues its control signals if either relay appears to be malfunctioning. Each controller runs an different, independently written firmware program to process the detected inputs to prevent a common firmware error.

Abstract: A ground fault circuit interrupter (GFCI) with built in intelligence is described that includes circuitry to automatically indicate a device miswiring condition. When a GFCI is wired with its AC and LOAD terminals reversed, downstream devices are still protected in the event of a ground fault but the duplex receptacle on the GFCI itself is not. The invention incorporates miswiring sense circuitry that automatically triggers the generation of visual and audible alarms in the event a miswiring condition is sensed. The invention employs an alarm inhibiting technique that incorporates sense circuitry connected to the AC terminals on one side of the internal GFCI switches or relays and alarm generation circuitry connected to the LOAD terminals on the opposite side.

Abstract: In a power distribution system, a reliable, accurate, and energy efficient fault circuit indicator is provided through a microcomputer-based fault current indicator design. First, reliability is improved inherently because the microcomputer, and the software embedded therein, replace the functionality of numerous discrete, less reliable electronic components found in prior designs. Second, the embedded software is capable of placing the fault current indicator in one of a number of energy conservation states, without compromising the fault current indicator's ability to provide information relating to the occurrence of a fault. Finally, greater fault current indication accuracy is achieved by detecting excessive line current, followed by a significant drop in line voltage.

Abstract: There is provided at least one pressure detector for detecting a change in pressure of an insulating medium, a vibration detector for detecting vibration of an oil-filled electric equipment, and a determination processor for determining, based on information detected by the pressure detector and the vibration detector, whether an internal short circuit has occurred in the oil-filled electrical equipment.

Abstract: A method and apparatus for improved indication of power-consumption status in a computer system is described. The computer system includes a light-emitting diode (LED) which produces an optical signal. The apparent intensity of the optical signal is controlled by a pulsed LED control signal having an adjustable duty cycle. By varying the duty cycle, the apparent intensity of the optical signal is varied. The rate at which the duty cycle is varied may be selected to produce an apparent intensity optical signal which varies continuously between a greatest and a least intensity. Also, the rate at which the duty cycle is varied may be selected from a plurality of rates, each corresponding with a one of a plurality of power-consumption states in which the computer system can operate.

Abstract: A circuit arrangement protects an FET power switch against damage from short circuits that may occur in the load connected between the drain terminal and an operating voltage source of the FET. The protection is achieved by the cooperation between a shunt resistor (3) connected between ground and the source terminal (S) of the FET and a gate voltage limiter (7) connected to the gate terminal of the FET. This cooperation limits the short circuit current through the FET until a short circuit detector (DT) provides a control signal that switches the FET off.

Abstract: A controller for a starter/generator used with an aircraft engine, includes means for monitoring field return current in a generator field winding; means for monitoring generator voltage; and microprocessor control means for adjusting generator field current as a function of the field current and voltage and field return current. The field return current and output voltage monitoring functions allow for open field, field integrity, over voltage, field weakening and torque limiting functions to be realized in an integrated programmable system configuration.

Abstract: Circuits for supervising message generators and audio output cables include memory for binary storage of messages previously recorded in a message generator. As the generator is cycled to produce an audio output, that analog output is sampled and compared to the previously stored binary representation. A match indicates a successful generation of the message. The cables can be supervised by applying a DC bias thereto and detecting the voltage present on the respective cable. Line integrity is indicated where the cable DC voltage falls in an expected range.

Abstract: The invention concerns a method for generating a fault indication signal in the event of a fault in an electric power supply network being monitored through a neural network arrangement. In order to rapidly generate fault indication signals capable of distinguishing between permanent metal contact short-circuits and short circuits due to arcing, a neural network (26) is used for each phase of the power supply network being monitored. Each neural network (26) is taught, while being coached through simulated voltages (U.sub.R (t)) of each phase during short-circuits caused by metal contact and arcing, so that the output signal (S) assumes a pre-defined value (0.8) for arcing and another pre-defined value (0.1) for a metal contact short-circuit. At the same time, the sequentially sampled normalized values (U.sub.Rn1 (t) through U.sub.Rn20 (t)) of the respective phase voltages (R.sub.

Abstract: Safety discharge circuit and method, capable of protecting workers from electric shocks during maintenance of high voltage electrical systems. A high voltage electrical system is placed inside a grounded box having a cover, releasably connected to the box. The circuit uses an electronic device adapted to sense the removal of the cover from the box and disable the high voltage electrical system. The electronic device is connected to the cover at its input and to the high voltage electrical system at its output, and is preferably a semiconductor controlled rectifier having a gate at its input. The semiconductor controlled rectifier is in a reverse blocking state when the cover is connected to the box, and is latched in a forward conducting state when the cover is removed from the box. The connection from the gate of the semiconductor controlled rectifier to the cover is made through mounting screws, which hold the high voltage electrical system connected to the cover.

Abstract: The noise received by the unused connectors limits the accuracy of a device for measuring the leakage from a piece of electronic medical equipment. To reduce noise the device is surrounded by a Faraday shield which encloses unused connectors of the device. The shielded connector includes a post having a transverse hole near its distal end. A coil spring surrounds the post end and is connected to the Faraday shield of the device. An insulated retainer prevents the distal end of the coil spring from extending beyond the end of the post. The retainer is compressed against the coil spring to expose the transverse hole when a lead is to be attached to the connector.

Abstract: An apparatus and method for determining a location and resistance of an electrical leak in a battery having a first and second terminals. The apparatus includes a resistor, a switch assembly for selectively connecting the resistor to the first terminal of the battery and for selectively connecting the resistor to the second terminal of the battery, and a controller.

Abstract: An ESD sensor includes a plurality of layers of dielectric material positioned on a substrate, each having a different thickness, a first contact positioned adjacent each of the plurality of layers and a plurality of second contacts, one each positioned on each layer of the plurality of layers of dielectric material. Each different thickness of each individual layer of dielectric material is formed to provide a specific voltage at which an electrical short will occur between the first and second contacts when an ESD appears thereacross, so that the sensor provides an indication of a range of voltages.

Abstract: Arcing in an AC power system is detected by monitoring the power waveform for wideband high-frequency noise, and examining the detected noise for patterns of variation in its amplitude synchronized to the power waveform. A narrowband, swept-frequency detector and synchronous averaging may be employed to improve discrimination of arc noise from background interference. An arcing fault interrupter for controlling a single circuit, and a whole house monitor, for detecting arcing anywhere in a house, are described.

Abstract: A three wire power supply circuit is provided comprising a circuit for monitoring the integrity of the ground connection of the power supply circuit. A circuit element is provided in the line-to-ground current path which conducts when current flows in the line-to-ground current path and is nonconductive when the ground connection is poor or absent. A microcontroller monitors the output of the circuit element and operates a buzzer or a light emitting diode to indicate when the ground connection is poor or absent.

Abstract: A ground fault circuit interrupter (GFCI) with built in intelligence is described that includes circuitry to automatically indicate a device miswiring condition. When a GFCI is wired with its AC and LOAD terminals reversed, downstream devices are still protected in the event of a ground fault but the duplex receptacle on the GFCI itself is not. The invention incorporates miswiring sense circuitry that automatically triggers the generation of visual and audible alarms in the event a miswiring condition is sensed. The invention employs an alarm inhibiting technique that incorporates sense circuitry connected to the AC terminals on one side of the internal GFCI switches or relays and alarm generation circuitry connected to the LOAD terminals on the opposite side.

Abstract: An instrument used for the live troubleshooting of short circuits in electronic equipment. This instrument has a current indicator, an adjustment to set the maximum current and electrical connectors. The short circuited line on the equipment to be repaired is opened and the connectors are connected, in order to complete the circuit. The instrument is adjusted to deliver a maximum current which is safe for the equipment when the equipment is functioning normally. The technician will now be able to troubleshoot the live circuit without causing further damage.