Abstract: An electrically operated equipment with a sealed enclosure containing circuitry with an exterior visual indicator to show a state of operation of the equipment. The visual indicator is illuminated by a magnetic flux sensor also exterior to the equipment, the sensor inducing an electrical current from a sensed magnetic flux passing through a permeable wall of the enclosure. The magnetic flux is provided by a magnetic field generator within the enclosure. The generator is connected to the equipment to generate the field when the circuitry is operating correctly whereby the indicator shows a correct state of operation. The invention avoids the use of sealed orifices in the enclosure for conductors to pass to exterior LEDs or LEDs sealed within the enclosure and possible resultant leakage. The invention is useful for optical network units. The invention also includes a visual indicating device of multi-layer configuration and a method of visually indicating the operational state of circuitry.

Abstract: A protective device includes a signal input intended for connection to a sensor, a signal output intended for connection to an evaluation unit, and an isolation element for galvanically separating the signal input from the signal output. The provision of the protective device prevents a transmission of overvoltages from the sensor to the evaluating unit.

Abstract: A water monitoring system and a water monitoring method for a high voltage cable including a conductor and a screen surrounding the conductor. At least a first water sensing wire extends in the screen between the cable beginning and the cable end and at least a second wire is connected with the first wire at the cable end to form a loop. A first switching unit is provided between the cable beginning and the measurement circuit. A control unit controls the first switching unit over a first predetermined time interval into a first switching state in which the water sensing wire and the second wire are connected to the screen potential. In a following second predetermined time interval the control unit controls the first switching unit into a second switching state in which the water sensing wire and the second wire are disconnected from the screen potential. The measurement circuit performs a water intrusion measurement in the second predetermined time interval.

Abstract: A high-voltage-proximity warning system has a local panel (1) for being positioned in or about a cab (2) of heavy equipment or other vehicle (5), a remote panel (3) in predetermined electrical communication with the local panel and one or more proximity antennas (4) for being positioned selectively on the vehicle in predetermined electrical communication with the local panel. The local panel is adapted to be push-button operable conveniently by an operator with gloved hands in a position where it is readily visible and easily connectable electrically to the remote panel and to the one or more proximity antennas. The remote panel is adapted to be positioned on or off of the vehicle where it can be protected for supportive operation and accessed for plural electrical connection to electrical devices that can include an electrical-source terminal (11), to speakers, and to warning and alarm communication devices (50).

Abstract: A hand tool which provides an alarm signal to a user as the tool approaches a live electrical wire is disclosed. The hand tool comprises a conductive tool head and a non-conductive handle. A non-contact voltage sensing circuit is provided in the handle of the tool. As the tool head approaches a live electrical wire, the non-contact voltage sensing circuit detects the voltage across the air gap between the tool head and the electrical wire, triggering an alarm circuit. The alarm circuit provides a visual or audio signal to the user.

Abstract: A voltage testing apparatus for electrical railways is disclosed consisting in one embodiment of a transportable pole-mounted electrical power indicator, electrically conducting wire-engaging means such as a hook attached to one end of the pole and electrically connected to the indicator, and a ground-connecting device such as an electrically conducting magnet also electrically connected to the indicator. An electrical circuit is completed between the cable, the indicator and the rail by placing the hook on an overhead railway cable and attaching the magnet to a roadbed rail. An LED array and voltmeter configuration constituting the indicator illuminate and show whether voltage is present.

Abstract: A hand tool which provides an alarm signal to a user as the tool approaches a live electrical wire is disclosed. The hand tool comprises a conductive tool head and a non-conductive handle. A non-contact voltage sensing circuit is provided in the handle of the tool. As the tool head approaches a live electrical wire, the non-contact voltage sensing circuit detects the voltage across the air gap between the tool head and the electrical wire, triggering an alarm circuit. The alarm circuit provides a visual or audio signal to the user.

Abstract: An apparatus for monitoring and controlling the operation of an electrical power transformer includes a processor with input transducers for providing to the processor inputs indicative of electrical current in a winding of the transformer and ambient temperature outside the transformer. The processor is arranged using an algorithm based upon heat transfer to repeatedly calculate a first prediction, based upon the present values of electrical current and ambient temperature, of a time period before the hot spot temperature exceeds a pre-set allowable maximum and a second prediction, based upon the current value of power, of a time period before the accumulated loss of life exceeds a pre-set allowable maximum. If the shorter time period of the two calculations is less than a pre-set value, for example one half hour, the processor generates an alarm signal and a display counting down the time remaining in the period, together with a second alarm signal at a shorter second time of for example one quarter hour.

Abstract: A apparatus for recording information on power surges in an electrical or electronic system is disclosed. The apparatus has a gas discharge tube connected between an input line of the electrical or electronic circuit protected and ground. The gas discharge tube is set to activate at a predetermined voltage. The gas discharge tube has adjacent to it a light sensor that reacts to discharges in the tube and the sensor in conjunction with enabling circuitry generates a signal representative of discharge of the gas discharge tube. The signal produced provides information on the time, magnitude and duration of discharges in the gas discharge tube, which are in turn representative of the power surge experienced by the system.

Abstract: An electrical utility meter having harmonic data templates advantageously enables a user to determine whether equipment at a particular site is susceptible to electrical damage or interference. According to an exemplary embodiment, the meter generates measured harmonic data for a plurality of phases in the polyphase electrical system. A user may select at least one of a plurality of predetermined templates including one or more harmonic data thresholds. Each of the predetermined templates corresponds to a condition where a specific device is susceptible to electrical damage or interference. The measured harmonic data is compared with the one or more harmonic data thresholds included in the at least one selected predetermined template. An alarm is generated when the measured harmonic data exceeds the one or more harmonic data thresholds included in the at least one selected predetermined template.

Abstract: The present invention relates to a digital meter for use of the current and voltage, including a front end signal processing device, a press button input device, a central processing unit (CPU), an LCD controller, an LCD, and an alarm device. When the signals detected by the front end signal processing device exceed the digital values of the maximum or minimum limit of the signal of the current and voltage set by the press button input device, the LCD controller may drive the LCD having different colors to light. Thus, the informed person may identify the detecting results of the current and voltage according to the different colors of the LCD.

Abstract: A apparatus for recording information on power surges in an electrical or electronic system is disclosed. The apparatus has a gas discharge tube connected between an input line of the electrical or electronic circuit protected and ground. The gas discharge tube is set to activate at a predetermined voltage. The gas discharge tube has adjacent to it a light sensor that reacts to discharges in the tube and the sensor in conjunction with enabling circuitry generates a signal representative of discharge of the gas discharge tube. The signal produced provides information on the time, magnitude and duration of discharges in the gas discharge tube which are in turn representative of the power surge experienced by the system.

Abstract: An apparatus for detecting a high impedance load on an output of a driver circuit having a power switching circuit providing output signals to a coil. Each output signal results from a drive signal that has a waveform comprising a higher magnitude initial peak period followed by a lower magnitude hold period. The driver circuit has a feedback circuit providing a difference signal as a function of a difference between an output signal and a corresponding drive signal. A diagnostic circuit connected to the driver circuit provides a high impedance error signal in response to detecting the difference signal crossing a threshold magnitude during a higher magnitude initial peak period of a drive signal.

Abstract: A computer system and method for preventing burnout of a Central Processing Unit (CPU). The computer system includes a CPU, a temperature sensor, a Direct Current to Direct Current (DC-DC) transformer, a hardware monitor and an ATX power supply. The CPU serves to execute computer programs. The temperature sensor is adjacent to or directly attached to the CPU for monitoring the operating temperature of the CPU. The DC-DC transformer is coupled to the CPU for providing CPU source voltage. The hardware monitor is coupled to the temperature sensor and the DC-DC transformer for monitoring the operating temperature and the source voltage of the CPU. The ATX power supply is coupled to the hardware monitor and the DC-DC transformer and controlled by a Post Power-Triggering Signal. When the operating temperature or the source voltage exceeds a permitted range, the hardware monitor sends a Post Power-Triggering signal to the ATX power supply to cut its output power off.

Abstract: An apparatus for detecting a high impedance load on an output of a driver circuit having a power switching circuit providing output signals to a coil. Each output signal results from a drive signal that has a waveform comprising a higher magnitude initial peak period followed by a lower magnitude hold period. The driver circuit has a feedback circuit providing a difference signal as a function of a difference between an output signal and a corresponding drive signal. A diagnostic circuit connected to the driver circuit provides a high impedance error signal in response to detecting the difference signal crossing a threshold magnitude during a higher magnitude initial peak period of a drive signal.

Abstract: An apparatus for monitoring and controlling the operation of an electrical power transformer includes a processor with input transducers for providing to the processor inputs indicative of electrical current in a winding of the transformer and ambient temperature outside the transformer. The processor is arranged using an algorithm based upon heat transfer to repeatedly calculate a first prediction, based upon the present values of electrical current and ambient temperature, of a time period before the hot spot temperature exceeds a pre-set allowable maximum and a second prediction, based upon the current value of power, of a time period before the accumulated loss of life exceeds a pre-set allowable maximum. If the shorter time period of the two calculations is less than a pre-set value, for example one half hour, the processor generates an alarm signal and a display counting down the time remaining in the period, together with a second alarm signal at a shorter second time of for example one quarter hour.

Abstract: The circuit in accordance with the present invention monitors current signals between the preamplifier and the transducer in a data storage device such as a disc drive utilizing magnetoresistive transducers and/or giant magnetoresistive transducers. The detector circuit includes an amplitude section, a duration section, a frequency section, and an alarm section. The amplitude section has a comparator for detecting when a signal exceeds a predetermined voltage level. The duration section measures the time period that the comparator has an output signal. The frequency section measures the frequency of occurrence of comparator output signals. Each of the sections provides an input to the alarm section which provides an alarm signal condition if the amplitude section magnitude is too high, or the duration times amplitude is too high, or the frequency of occurrences of events is too high.

Abstract: A wearable electric field detector has a housing mountable on a user's person and including a sensing circuit responsive to an electric field to generate a signal which varies in proportion to the strength of the sensed field, and an alarm circuit coupled to the sensing circuit for producing an intermittent audible alarm signal, which has a repetition rate varying in proportion to the strength of the field, and a visible alarm signal. A mute circuit is manually activatable for selectively muting the audible alarm and then automatically reenabling it after a predetermined time period. The detector includes a manually-actuatable test circuit. There is no on-off switch, the detector being disabled by being disposed in a shielded carrying case.

Abstract: A power surge detection device is disclosed to investigate if there is any power surge occurring to a main processor in a computer system. When the width or frequency of power surges detected jeopardize the normal operation of the computer system, an alerting signal, for example, an interrupt signal or a power management signal, is sent to the main processor to intervene in the normal operation of the computer system so as to avoid the power instability period.

Abstract: Overload protection is provided to the tuned receiving front end circuitry of an RFID tag by selectively detuning the tuned receiving front end in response to sensed voltage overload generated across the tuned receiving front end by a high field. The tuned receiving front end is or is modeled as a tuned parallel inductor and capacitor tank circuit. A parallel capacitance is added to the tank circuit by means of a control transistor which is controlled by a voltage sensing circuit. The voltage sensing circuit senses the voltage being applied across the tank circuit and turns on the control transistor to a degree to sufficiently detune the tank circuit so that the operating voltage across the tank circuit remains at or below a desired operating value or safe limit regardless of the value of the field in which the RFID tag is placed.

Abstract: Methods and systems consistent with this invention detect a failed short thyristor in a solid-state controller for delivering power to a load during reduced-voltage operation. Methods and systems consistent with this invention detect a voltage across the thyristor, and indicate a failed short thyristor when the absolute value of the voltage across the thyristor remains below a threshold value during a predetermined period of time. Methods and systems consistent with this invention detect a failed open thyristor in a solid-state controller during full-voltage operation. Methods and systems consistent with this invention detect a voltage across the thyristor, and indicate a failed open thyristor when the absolute value of the voltage across the thyristor exceeds a threshold value.

Abstract: The present invention relates to a circuit arrangement to monitor a regulated output voltage in an automotive vehicle, wherein the regulated output voltage is monitored as to whether defined threshold values have been exceeded and/or have fallen short of, wherein the circuit element for regulating the output voltage and the circuit element to monitor whether threshold values have been exceeded or have fallen short of are integrated in one chip, wherein the adjustment of the output voltage is effected by way of a first reference voltage, and wherein monitoring of the threshold values as to whether they have been exceeded or have fallen short of is conducted by way of a second reference voltage.

Abstract: For use with a DC fan, a detection circuit and a method of detecting an operational condition thereof. In one embodiment, the detection circuit includes: (1) a sensor, coupled to the DC fan, that senses a current through the sensorless DC fan and produces an intermediate signal based thereon and (2) an alarm circuit, coupled to the sensor, that compares the intermediate signal to a range defined by an upper limit signal and a lower limit signal and generates an alarm signal when the intermediate signal is outside of the range.

Abstract: An alarm apparatus for a vehicle-onboard AC generator has an alarm function improved owing to detection of both output voltages of a pair of armature coils of the generator. The alarm apparatus includes an AC generator (1) driven by an engine of a motor vehicle and including a field coil (10) and a pair of armature coils (11, 12), a pair of rectifier circuits (21, 22; 21A, 22A) for rectifying output voltages generated by the paired armature coils (11, 12), respectively, a battery (5) charged by rectified outputs of the paired rectifier circuits (21, 22; 21A, 22A), a voltage regulator (3) for regulating the output voltages of the paired armature coils (11, 12) on the basis of either rectified output voltages of the rectifier circuits (21, 22; 21A, 22A) or a terminal voltage of the battery (5), and an alarm means (4A, 49) for generating an alarm when at least one of the output voltages of the paired armature coils (11, 12) deviates from a predetermined value (VR2).

Abstract: An alarm device is designed to warn of danger of hitting high voltage overhead power lines by a crane in motion. The alarm device is composed of an electric-field sensor for detecting the alternating electric field of the overhead power lines and for outputting an alternating current, which is then converted or amplified by an amplifier connected with the electric-field sensor. An alternating voltage is outputted by the amplifier such that the alternating voltage is rectified and filtered by a rectifier/filter circuit connected with the amplifier. A direct current voltage output is brought about by the rectifier/filter circuit. A starter is disposed between the rectifier/filter circuit and a wireless transmitter capable of being activated by the starter to transmit a wireless signal at such time when the value of the direct current voltage exceeds a preset value. The alarm device is further composed of a wireless receiver/alarm for receiving the wireless signal and for effecting a warning signal.

Abstract: A sensor system for use on drilling equipment to detect the presence of high voltages during horizontal or vertical drilling and providing an alarm signal corresponding to one of three possibilities: (1) the drilling tool hitting a high voltage line; (2) the drilling tool remaining in contact after hitting the high voltage line; and (3) an exposed or damaged high voltage line in close proximity to the drilling implement. The sensor system detects alternating current, converts the alternating current signal to a pseudo square waveform signal, compares the magnitude of the square waveform signal with a reference voltage, and sounds an alarm if the magnitude of the square waveform signal exceeds the reference voltage. The sensor system also incorporates a self-test circuit which allows an operator to check its functionality before use. The operator can also check the sensor at any time during drilling process.

Abstract: A tester for checking the impedance of an electrical circuit by measuring the percentage voltage drop of the circuit resulting from the application of a user-supplied load. The tester includes connection means suitable for connection into the electrical circuit to be tested. The tester stores a sample of the voltage present at the connection. As the user applies a load to the circuit, the tester compares the sampled circuit voltage to the loaded circuit voltage. If the voltage difference after a set delay time is greater than a set percentage, an indicator on the tester alerts the user to this fact. A large voltage drop in a circuit can be an indication of hazardous wiring conditions, possibly due to corroded or loose connections, improper wire size, or other faulty components in the circuit.

Abstract: A warning device of overload or overheat for the electric cords, cables, sockets comprisng with a, or some warning strips having evident colors at proper location on a PVC power cord, and having heat-sensing layers applied on the warning strips, whereby, when the power cord is overloaded with a large current, the copper wire thereof is gradually heated, and temperature on the PVC power cord is raised accordingly, then the dark heat-sensing layers become transparent gradually, and the colors of the sensing strips appear, so that an effect of detecting whether the electric cord is in overload, or overheat can be achieved.

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 comparison circuit (4) is formed by a Schmidt buffer (4a) which has first and second threshold values and a buffer (4b) whose threshold value is larger than the first threshold value but smaller than the second threshold value. An integrating circuit (3) and the comparison circuit (4) function as a timer circuit which operates in accordance with comparison of the three values. An input signal (IN) decreases from a reference voltage signal (V6). A control signal becomes an H level after a time which is determined by a time constant of the integrating circuit (3) and the threshold value of the buffer (4b), and a detect signal (FO) is outputted after a time which corresponds to a difference between the second threshold value and the threshold value (which is equal to or shorter than a response time of the circuit (4)). During monitoring of a d.c.

Abstract: A surge protector module is provided with a housing with an internal space, a separator disposed within the housing which divides the internal space into first and second spaces within the housing, and a surge protection device. The surge protection device has a surge protector mounted within the first space and a disconnect mechanism operable to conductively disconnect one of the terminals of the surge protector from one of the terminals of the surge protection device in the presence of a prolonged overvoltage surge across the terminals of the surge protector. A combustion-retardant material is disposed within the housing of the surge protector module so that it occupies only the first space within the housing, leaving the second space within the housing substantially free of the combustion-retardant material, and the disconnect mechanism is disposed in the second space in which no combustion-retardant material is disposed.

Abstract: Lightning strikes on or proximate to an optical fiber cable may be detected via a lightning detector (18) that monitors the characteristics of voltage present on a metallic sheath (12) associated with the cable. The lightning detector (18) detects excessive voltage levels, spikes and/or frequency variations associated with a lightning strike and generates an alarm signal communicated to a central monitoring facility.

Abstract: A modified surge protector is provided including a housing having a pair of male contacts for being inserted into a power receptacle to receive power therefrom. Associated therewith is a pair of female contacts for releasably receiving a plug of an appliance to supply power thereto. Also included is a power switch connected between the male contacts and the female contacts for allowing the flow of power therebetween only during the receipt of an activation signal. A power variation sensor is connected to the male contacts for detecting a variation in power received therefrom. A delay is included for generating a delay of a predetermined amount of time, wherein the activation signal ceases during the delay of the predetermined amount of time.

Abstract: A method and device for monitoring the production of a high voltage for use in electrostatic application of a coating product, the high voltage being produced by a generator and the monitoring being performed by a circuit for measuring an electrical parameter associated with the high voltage, together with verifying operation of the circuit immediately following start-ups of the generator.

Abstract: A circuit breaker has line and load terminals and a mechanism which indicates the magnitude of current flowing through the circuit breaker. The mechanism includes a current sensing resistor coupled between the supply and load terminals. An amplifier is coupled to the current sensing resistor and produces a first output signal corresponding to the current magnitude. A first light emitting diode is energized by the first output signal. A first comparator is coupled to the amplifier and produces illumination of a second light emitting diode when the first output signal exceeds a first reference voltage level. A third light emitting diode is illuminated by a second comparator when the first output signal exceeds a second reference voltage level. Thus the number of light emitting diodes that are illuminated indicates the relative level of current conducted by the circuit breaker.

Abstract: The position of a boring head (16) during boring operation in the vicinity of an existing utility conveyance (22) that radiates a locating signal can be determined by establishing the ratio of the strength of the locating signal of the cable induced in the boring head to the strength of the locating signal on the conveyance. Should the ratio exceed a prescribed value, indicating that the boring head is too close to the existing conveyance, then an alert is generated. Advantageously, the position of the boring head during a boring operation may be controlled in feed-back loop fashion in accordance with the ratio to maintain the boring head substantially parallel to the existing conveyance.

Abstract: The invention relates to a circuit arrangement for testing the operation of a current monitoring circuit for a power transistor. The power transistor consists of several single transistors of the same size connected in parallel, through which a fraction of the total current supplied to the power transistor flows. A monitoring signal proportional to the current flowing through one of the single transistors, is supplied to the current monitoring circuit, which generates an alarm signal when this monitoring signal exceeds a specified threshold value. The single transistors are divided into a group containing a small number of single transistors (T.sub.1.1 -T.sub.1.9) connected in parallel and a group with a larger number of single transistors (T.sub.2.1,1 -T.sub.2.2,9) connected in parallel, which can be driven independently of each other, where the single transistor (T.sub.S) supplying the monitoring signal belongs to the smaller group.

Abstract: A removable battery pack for powering a pen-based or portable computer system in which the battery pack blocks its terminals when inserted into an unknown system. The known system includes a power supply microcontroller which passes battery charge data back and forth between a memory located in the battery pack and the power supply microcontroller. A battery microcontroller, located in the battery pack, eavesdrops drops on the communication between the power supply microcontroller and the memory, and when it validates a known signature of this communication, the battery microcontroller then enables the terminals of the battery pack. A trickle discharge current flows from the battery pack whenever the battery pack is out of the known system to allow the power supply microcontroller to power up in the case of a dead auxiliary battery.

Abstract: An invalid reference detection circuit formed on a semiconductor chip having: reference input terminals adapted for coupling to a reference source external to the chip; a local reference source; and comparison circuit. The comparison circuit is responsive to the local reference source and a condition at the reference input terminals to detect an invalid condition at the reference input terminals and to produce an output signal indicative of the detected invalid condition. The invalid condition at the reference input terminals may be an open circuit condition at at least one of the reference input terminals, a condition when the voltage across the reference input terminals is below a predetermined minimum voltage level, a condition when the voltage across the reference input terminals is above a predetermined maximum voltage level, and/or a short circuit condition. An analog/digital conversion system is formed on a semiconductor chip together with the invalid reference detection circuit.

Abstract: A system for registering a malfunction in telecommunications equipment comprises a protective device including a terminal connector pin and a ground pin connected to ground. The system also includes a housing member for housing the protective device, the housing member including a conductive member attached thereto. A main failsafe switch connects the terminal connector pin to ground through the ground pin in the event of an overvoltage, while an alarm switch connects the conductive member attached to the housing member to ground in the event of the overvoltage. An overvoltage sensitive member contacts both the main failsafe switch and the alarm switch, and retracts both the main failsafe switch and the alarm switch while in a normal operating state of the telecommunications equipment. The overvoltage sensitive member releases both switches in the event of the overvoltage.

Abstract: A portable communication device with battery conservation capability is capable of sensing (223) its power source and suppressing a battery conservation circuit depending on an actual voltage determined (225) from an analog-to-digital converter. Two or more voltage ranges are defined (227) such that battery conservation is disabled when an external power source is operated in one of the predetermined voltage ranges.

Abstract: A method for detecting the presence of a spark in an electronic ignition system. The method consists of generating an overvoltage event and then generating a voltage signal proportional to the overvoltage event. The onset of the overvoltage event is detected by comparing the voltage signal to a starting threshold voltage and in response is provided a first signal at a high logic level. The first signal is maintained at said high logic level during the time duration of the overvoltage event. The termination of the overvoltage event is detected by comparing the voltage signal to an ending threshold voltage, which is lower than the starting threshold voltage and proportional to a supply voltage of the electronic ignition system, and in response is provided a second signal at a low logic level. The time duration of the first signal is detected and then the presence of a spark is signalled if said time duration exceeds a reference value.

Abstract: Currents input to and output from a device, such as a heater, in a daisy chain connection are measured and compared. Failure of an individual device, as well as device location, is indicated if no current is consumed by the device. A latch is activated in response to detection of a non-functioning device, sending a signal that gives notice and location of the failure.

Abstract: A barrier device threadably mounts to a cabling aperture on a field mounted transmitter. The field mounted transmitter receives and transmits signals, and is wholly powered by a current loop circuit. The barrier device has a conductive housing with at least a first and a second aperture and a pair of conductors passing through the first aperture of the barrier device, for connecting to a terminal block in the transmitter. A pair of signal terminals, preferably as ring tongue lug, is mounted in the second aperture of the barrier device. The signal terminals are connectable to a handheld communicator, which is used to calibrate, monitor and test the transmitter. A barrier circuit is mounted in the housing and is electrically connected between the signal terminals and the conductors. Signals from the communicator access the terminal block through the barrier circuit, and the barrier circuit limits the power available at the signal terminals.

Abstract: The invention relates to a method for supervising the functioning of a plurality of valve units, a system for performing the method, a control unit and a control assembly for cooperation with the control unit. Each valve unit in the system comprises a semiconductor element (THY1-THYN) and a control unit for controlling the semiconductor element. The control unit comprises a trigger order input for receiving a trigger order (FP), an indication output for emitting a first indication signal (TP) and a trigger signal output (100) for emitting a trigger signal to the semiconductor element. The method comprises the steps: detecting a positive forward voltage (U.sub.T) across the semiconductor valve, generating a first indication signal (IP) when the forward voltage (U.sub.T) exceeds a first threshold value (U.sub.1), generating a trigger signal upon detected receival of the triggering order signal (FP), and the step: generating a second indication signal (SSTP) when the forward voltage (U.sub.

Abstract: An electrical strike sensing system for providing an alarm if the underground boring equipment encounters a potentially hazardous condition. The system senses current carried through the equipment, as well as the voltage between the equipment and a reference. The measured current is converted to a percentage of a reference current, and the voltage is converted to a percentage of a reference voltage. The current and voltage percentages are added, and if the sum exceeds 100%, the alarms are activated. The current and voltage percentages, as well as the date and time of the strike, are stored in a nonvolatile memory.

Abstract: The indicating device (3) is used for signalling a faulty condition of an electrical apparatus, in particular of a surge arrester (1). It contains a sensor (resistor 10) which is located in an insulating material housing (6) and is intended for detecting a fault current flowing through the apparatus, as well as a two-piece metal housing (4) surrounding the insulating material housing (6). The sensor (10) and the insulating material housing (6) are part of a switching element (5). This switching element (5) causes the insulating material housing (6) to spring apart, by the formation of compressed gas, when the fault current occurs and displaces the two parts (shells 12, 13) of the metal housing (4), making the indicating element (16) visible and forming a DC connection which carries the fault current.

Abstract: In a computer system having a computer bus drive circuit capable of providing drive current to an individual line of a computer bus coupled thereto, a circuit for determining a proper level for the drive current and a method of making such determination. The circuit comprises: (1) a detection circuit, coupled to the individual line of the bus, for monitoring a response of the individual line of the bus to changes in state thereof during an operation of the computer system and providing an indication of the response and (2) a drive current establishment circuit, coupled between the detection circuit and the computer bus drive circuit, for establishing the proper level for the drive current in response to the indication produced by the detection circuit during an operation of the computer system.

Abstract: Air bags are deployed by firing circuits each containing a squib in series with a common control switch, and a control containing an accelerometer and a microprocessor for operating the switch to deploy the air bags. To diagnose shorts, a current source feeds a trickle current through each squib and a current limited voltage regulator across the switch passes the combined trickle currents to ground. The microprocessor senses the voltage across the switch via an A/D converter. That voltage goes low for a short to ground and high for a short to battery voltage.

Abstract: The present invention relates to an LED traffic signal light containing numerous LEDs and a voltage compensation circuit which allows the traffic light to operate over a wide range of input power voltages, while generating sufficient light intensity to control traffic at a highway intersection. The voltage compensation circuit achieves these objectives without substantially increasing the power consumption, overall cost, or failure rate of the LED traffic signal light. In the preferred embodiment, the voltage compensation circuit disables or rearranges a first and then a second set of LEDs in the traffic light, as the input power voltage drops below a first and then a second threshold voltage, so that the remaining LEDs will be driven by an increased current and generate a greater overall light intensity than if all of the LEDs were driven by the decreased current that would result from the decreased input power voltage.