Abstract: An anti-theft power cord for use with electrical devices has sensors for detecting removal of the cord from an electrical receptacle and for detecting the removal of the cord from the device sought to be protected. Control systems associated with each of the sensors activate alarms when receiving signals from the sensors. The control systems, comprising microcontrollers, also communicate with one another along the power cord and will sound an alarm if the cord is cut. A battery backup system is provided to allow the power cord to function as an anti-theft device even during a power failure without sounding false alarms.

Abstract: The present invention provides a digital automatic power interruption and re-supply relay for performing detection and comparing operation to inform a state of an accident with voice and numerals and automatically operating a connected relay to interrupt power when there occur abnormal changes such as interruption of electric power, open-phase, anomalous voltage, unbalanced voltage, negative-phase, overcurrent, and electric leakage in a power transmit and supply line of high and low voltage or special high voltage and high (low) voltage and, after compensating for the accident, for automatically re-supplying the power.

Abstract: A wireless switching system includes a central transmitter unit which generates a plurality of electromagnetic frequencies. A plurality of switches within the electromagnetic field each selectively open and close a resonant circuit having a unique resonant frequency. When the user activated switch closes its associated resonant circuit, the resonant circuit consumes energy from the electromagnetic field at its resonant frequency. The central transmitter unit detects this energy consumption and the frequency at which the energy consumption occured and consequently activates a vehicle function associated with the closed user activated switch.

Abstract: Disclosed is a method and arrangement for use in an electrical utility meter, the electrical utility meter operable to be connected to a plurality of electrical service types. The arrangement is operable to identify a present service type, the present service type being one of the plurality of electrical service types to which the electrical utility meter is connected. The arrangement comprises: conversion circuit for obtaining measured voltage magnitude and phase angle data for a plurality of phases in a polyphase electrical system; a memory; and a processor connected to said memory and said conversion circuit. The processor is operable to execute programming steps stored in the memory to receive the measured voltage magnitude and phase angle data from the conversion circuit and identify the present electrical service type based on the measured voltage magnitude and phase angle data.

Abstract: The current through the coil of a solenoid valve is monitored for a deflection which is generated when the valve armature shifts in response to the current being applied to the coil. A lack of detection of the deflection is indicative of a solenoid malfunction and causes generation of an alarm signal.

Abstract: The present invention includes an apparatus and method of monitoring a power transmission line. According to one embodiment, an apparatus adapted to monitor a power transmission line supported by a plurality of structures includes a first measuring device located at a position in space; and a second measuring device coupled with the power transmission line, the first measuring device and second measuring device being configured to provide position information of the second measuring device relative to the first measuring device.

Abstract: An electrical static eliminator device performance indicator including a sensor for sensing the ion flow from an emitter point of the static eliminator device and also for sensing the presence of a voltage at an emitter point to accurately detect the fouling of a point or shorted point condition; a display, responsive to the means for sensing, for displaying an indication of a fouled emitter point or a shorted emitter point; and an electrical circuit interconnecting the sensor and the display.

Abstract: This invention solves the problem of differentiating between a short-circuit and a low resistance value. A multi-tester impresses voltage across an LED circuit in inverse correspondence with the resistance of a subject circuit. A low-resistance voltage divider, including a circuit under test having an unknown resistance R.sub.X as a first shoulder or voltage portion, causes a threshold voltage to be impressed across the LED, thereby causing the LED to emit light for circuit resistance values at or below a maximum detectable resistance R.sub.X1. Shorts are detected by switching a shunt resister defining a second shoulder or voltage portion into parallel relationship with the LED circuit. The shunt resister has a low resistance which decreases the sensitivity of the LED to such a point that the threshold voltage is impressed across the LED for a circuit resistance R.sub.X2 of near zero amount.

Abstract: A power measurement system calculates the power flow within a wire to a customer and transmits an indication of the power flow to a remotely located operator. The measurement system includes both a current transformer that senses current within the wire and generates a first output signal and a voltage input that senses voltage within the wire and generates a second output signal. A measurement device receives both the first and second output signals and in response generates a third signal representative of the power flow within the wire. The measurement device includes both a speech encoding circuit that receives the third signal and in response generates a voice signal, and a transmitter that receives the voice signal and transmits the voice signal to the remotely located operator.

Abstract: A frequency detection circuit has a transistor switching device between first and second electric potentials, and a gate applied with a clock signal. A resistor and a capacitor are connected in parallel between the output of the transistor switching device and the second potential. The capacitor is charged toward the first potential when the clock signal assumes one level and discharged toward the second potential in accordance with a time constant determined by the resistor and the capacitor when the clock signal changes to the other level.

Abstract: In the case of a multichannel monitoring device for monitoring system operating states, a test input (45a, 45b) is provided per channel (2, 3) on an evaluation and monitoring circuit for the purpose of testing the supply leads (7a, 7b) to the signalling units (1a, 1b) for freedom from damage. Either no filters or filters (47a, 47b) with a short settling time are provided in the supply lead to this test input (45a, 45b). As a result, testing requires only a very short time, so that the evaluation of the signalling units (1a, 1b) is interrupted only for a very short time. The time is so short that no dangerous system states can occur.

Abstract: The system for determining protection quality of a protective relay and related functions of the protection system include obtaining information concerning the output status of the various protective elements in the relay. The status of various operations in the protective element are also evaluated against specific standards. The operation of supervisory and control elements affecting the action protective elements are also evaluated. Other aspects of the relay, including the availability of the relay and the operation of the voltage and current transformers are also evaluated. In addition, associated aspects such as the status of the communication channels, the station voltage availability and the condition of the trip and close circuits are monitored. All of the above is analyzed in a summary report to provide an indication of protection quality for the relay and associated protection system functions.

Abstract: In a method for frequency analysis of a signal of a hazard detector, wavelet transformation is combined with fuzzy logic analysis. In the transformation, based on orthonormal or semi-orthonormal wavelets, an original signal is fed to a multi-stage filter cascade of pairs of high-pass/low-pass filters. From the output of the high-pass filter, wavelet coefficients and values of the original signal, each filter stage produces an association function. The functions are normalized and analyzed further in accordance with fuzzy logic rules. The method is particularly suitable for analyzing signals from flame detectors, noise detectors and the like. As processor code for transformation and analysis is kept short, high speed and accuracy are achieved at low cost.

Abstract: A combination of circuits is responsive to a respective one of a definite number of operation patterns of a plurality of PTCs, the operation patterns being different therebetween and including a plurality of first patterns each respectively representative of an operating state of a corresponding PTC thermally operated, for providing a signal with a corresponding one of a definite number of signal states representing the operation patterns, respectively, and a common LED is operable by the signal with a respective signal state to provide an identifiable indication relative to an indication by the signal with any other signal state.

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: The audible alarm system of the present invention incorporates an alarm condition indicator that is designed to detect an alarm condition within the AED. The audible alarm system further incorporates an audible alarm circuit that is connected to the alarm condition indicator and is designed to produce an audible alarm. The audible alarm circuit is initially activated by the alarm condition indicator and then operates independently of the alarm condition after the initial activation.

Abstract: A safety apparatus for electric appliances which includes a sensor for sensing that an electric appliance is operating. An alarm coupled with the sensor, whereby an alarm is initiated. A manually operated alarm disabling switch permitting a person supervising the operation of the electric appliance to temporarily disable the alarm for a predetermined time interval.

Abstract: A sensor assembly and method of forming the sensor assembly for sensing count and tamper, where the count is related to an energy field having a gradient along an axis of sensitivity and where the tamper is related to a static energy field and where the energy comprising the static energy field is the same type as the energy comprising the energy field having a gradient, includes an energy gradient detector that has at least a first sensor spaced apart from and communicably coupled to a second sensor along the axis of sensitivity. A static energy detector that has at least a first shielded sensor, the shielded sensor being substantially shielded from the energy field having a gradient and from the static energy field. A second unshielded sensor is communicably coupled to the shielded sensor. The invention further includes a method of detecting a spatially varying magnetic field.

Abstract: A indicating power cord system including a housing and an elongated extension cord having a first end connected to the housing and a second end having a plug coupled thereto for being releasably inserted in a standard electrical receptacle to receive power therefrom. Next provided is an electrical outlet positioned on the housing for being electrically connected to a block heater of a vehicle. The electrical outlet is electrically connected to the extension cord with a relay contact and associated relay coil connected therebetween. The relay contact has a closed unbiased orientation upon the lack of receipt of current by the relay coil and an open biased orientation upon the receipt of current by the relay coil. Also included is a thermistor positioned on the heater block of the vehicle. The thermistor can be connected to the relay coil for providing current thereto upon the engine block reaching a predetermined temperature.

Abstract: A fault sensor device comprising a receiver (3; 3A; 3B) for receiving microwaves (2, 8) radiated from an object to be monitored (1; 1A; 1B; 1C; 1D; 1E; 1F), a detector (4) connected to the receiver (3; 3A; 3B) for converting and outputting the microwaves (2, 8) into a video signal (2S4; 2S21), and a signal processor (5) for converting the video signal (2S4, 2S21) output by the detector (4) into a presentation signal (2S5) and outputting the presentation signal (2S5) to an external presentation device (91; 91A), and for determining whether or not the microwaves (2, 8) received are associated with a fault, based on one of the duration and the frequency of the video signal (2S4; 2S21) and the level of the video signal, and for issuing an alarm signal (2S6) when the determination reveals that the microwaves are associated with the fault.

Abstract: An apparatus for detecting abnormal radio-frequency signals has an antenna responsive to a radio-frequency signal. The radio frequency signal has a plurality of signal components, each of which has an associated amplitude. A circuit attenuates each of the plurality of signal components having an amplitude not greater than a threshold value and generates a suspect signal comprising each of the plurality of signal components having an amplitude greater than the threshold value. A circuit then compares the suspect signal to a plurality of preselected signal types. When the suspect signal does not correspond to any of the preselected signal types, a circuit generates an alarm. In a method of detecting usage of a radio-frequency weapon, a signal having an amplitude, is received. A background signal amplitude of a plurality of components of the signal is determined.

Abstract: Switching devices can have means for contactless switching position detection. According to the invention, magnetic field sensors arranged at suitable locations inside and/or outside a device housing are provided for switching position detection. In particular, position-dependent magnetic fields are measured for ON/OFF position detection, overcurrent triggering, and contact welding; however, the magnetic field of the current flowing is detected to recognize short-circuit triggering. Differential Hall effect sensors and Reed contacts, respectively, can be used for these purposes. In addition, a sound sensor can be provided for detecting the switching noise, whose signal is evaluated together with the overcurrent triggering signal for short-circuit detection.

Abstract: A method and apparatus for detecting power quality or disturbance events, such as voltage swells, sags or impulses, in power signals at remote locations of a power distribution system and for conveying information relating to the power disturbances to a central location. Voltage and/or current signals in electric power lines are monitored and converted to low level analog signals. The low level signals are processed by analog processing circuits or are digitally sampled and processed by digital processing circuits to detect power disturbances. Each power disturbance is characterized according to multiple parameters. The characterization information is encoded into a single signal. This is done by assigning a subset of a range of possible values of the signal to represent a parameter and then assigning a value within each subset of the range to represent another parameter.

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 novel line-current protection circuit that is useable with a PCMCIA modem card is disclosed. The protection circuit is adapted to detect when an excessive voltage is present across the tip and the ring leads of a telephone subscriber loop by sensing the amount of line-current being supplied to line interface circuitry disposed on the PCMCIA modem card. The protection circuit includes a current sensing circuit portion that is placed in series with the tip lead and which detects when the line current exceeds a predetermined maximum amount. In the event the line current exceeds the maximum amount, the current sensing circuit asserts an excessive line current signal which is being monitored by a digital processor. The digital processor responds by causing a relay circuit to be opened, thereby causing the PCMCIA modem to be in an "on-hook" state.

Abstract: There is disclosed a device for measuring the magnetic field strengths associated with a.c. electrical currents over a protracted period of time and, as required, in hostile environments. A preferable application calls for the determination of the field strengths associated with electrical currents flowing in the a.c. power distribution lines of utilities. The device includes a monitoring instrument positioned in relation to the power lines to be monitored, typically at the base of a pole immediately adjacent the pole of the power line or on a power line supporting pole itself. In order to provide for long term, powering of the monitoring device, d.c. power is developed utilizing the a.c. power that is present. The conversion from a.c. to d.c. is effected at a distance sufficiently far from the monitoring instrument so as not to have any consequence on the readings that are being taken. Readings during the protracted period are typically stored and then accessable at pre-determined periods.

Abstract: An isolated fault monitoring circuit for a AC port in an AC I/O module for a programmable logic controller is taught. Briefly stated, a bridge circuit is series connected to a fuse and an optocoupler. When the fuse which is in series with the AC input line is blown, the output of the optocoupler produces a voltage one-half of that during steady state operation thereby causing one of two comparators to go high which in turn causes an LED to light indicating a blown fuse. Should the AC input line be disconnected or otherwise not present, the optocoupler produces no output which thereby causes the second of the two optocouplers to have its output go high thereby causing a second of the two LEDs to light so indicating that condition. At any time during the fault condition only one of the LEDs will light, while no LEDs are lit during steady state operation.

Abstract: A load insulator 2, for interposition into a loaded line, comprises a plurality of mechanical links 4 connected together to form a chain, and an electrical insulator 8 arranged between a pair of adjacent interlocked links 10,12 in the form of an insert of insulative material to electrically isolate the links 10,12 of the pair from each other. A load sensing device may be provided for sensing the strain on the mechanical link. A measuring device 24 for measuring the resistance of the insulator 8 is provided to check the electrical condition of the load insulator, whilst a recording and indicating device allows for recording of electrical strikes and provide a lifetime expiry indicator.

Abstract: There is disclosed a methodology for measuring the magnetic field strengths of fundamental and harmonic frequencies associated with a.c. electrical current flows over a protracted period of time; and, particularly, in hostile environments. A preferable application calls for the determination of the field strengths associated with electrical currents flowing in a.c. power, distribution lines of utilities. The monitoring instrument is positioned in relation to the power lines to be monitored, typically at the base of a pole immediately adjacent the pole of the power line or on a power line supporting pole itself. In order to provide for long term, powering of the monitoring device, d.c. power is developed utilizing the a.c. power that is present. The conversion from a.c. to d.c. is effected at a distance sufficiently far from the monitoring instrument so as not to have any consequence on the readings that are being taken.

Abstract: A voltage detection circuit includes a first resistive arm receiving an internal voltage to produce a basic current, current amplification circuitry to produce a reference current proportional to the basic current, a second resistive arm to produce a reference voltage representing the reference current, a voltage source to produce a control voltage from the reference voltage and a logic circuit to produce a binary signal from the control voltage, the state of the binary signal representing the value of the internal voltage.

Abstract: A branch circuit includes an branch breaker, a master outlet, and two slave outlets in series with the master outlet. The master outlet is the closest of the outlets to the circuit breaker. It includes a power sensor, the output of which is graphically displayed on a multi-segment LED display visible from the front of the outlet. The power sensor output is also supplied to displays at the slave outlets so that the power measured at master outlet is indicated at all outlets. This allows the available power capacity for the branch circuit to be appropriately indicated at all outlets on the circuit. The design can be implemented inexpensively enough that it is economical to employ the invention at every outlet in a building.

Abstract: A self-excited microelectromechanical device is described. The device includes a resonating structure, such as a cantilever, which responds to a physical phenomenon by generating an induced variable frequency voltage signal corresponding to the physical phenomenon. Self-excitation circuitry connected to the cantilever processes the induced variable frequency voltage signal and produces a variable frequency voltage signal in a resonant pass band of interest that is applied to the cantilever to augment the effect of the physical phenomenon on the cantilever. An exemplary use of the device is as a power line sensor. In this context, the cantilever responds to the electric field associated with a power signal on a power line. The cantilever transforms the voltage signal of the electric field into a corresponding frequency signal. The noise-immune frequency signal can be readily processed to reconstruct the power signals carried by the power line.

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: A method for monitoring an electrical drive, in particular a drive of an armature, having electric supply lines being extended through a switchgear plug-in unit associated with the drive and being connected at the plug-in unit to a measurement and evaluation unit, includes connecting at least one of the supply lines to the measurement and evaluation unit through a current transformer, and simultaneously operating and monitoring the drive with the plug-in unit. An apparatus for monitoring the electrical drive includes a switchgear plug-in unit associated with the drive. Electric supply lines of the drive extend through the plug-in unit. Voltage pickups and current pickups are disposed at the plug-in unit for a measurement and evaluation unit. Voltage measuring lines in the plug-in unit begin at the supply lines and end at the voltage pickups. Current transformers in the plug-in unit are associated with the supply lines without interrupting the supply lines.

Abstract: A testing wristlet seat using an oscillation circuit to test a test lead which is grounded to discharge the static electricity produced in the manufacturing procedure. In case the test lead is broken or poorly grounded, the grounding condition will no more exist. At this time, the oscillation circuit oscillates and generates a frequency to make an inner buzzer emit warning sound to inform the user of the breakage of the circuit. An LCD display screen is disposed on the wristlet seat for displaying time in normal condition. In case a failure takes place, the display screen displays a fail signal for the user.

Abstract: A load insulator 2, for interposition into a loaded line, comprises a plurality of mechanical links 4 connected together to form a chain, and an electrical insulator 8 arranged between a pair of adjacent interlocked links 10,12 in the form of an insert of insulative material to electrically isolate the links 10,12 of the pair from each other. A load sensing device may be provided for sensing the strain on the mechanical link. A measuring device 24 for measuring the resistance of the insulator 8 is provided to check the electrical condition of the load insulator, whilst a recording and indicating device allows for recording of electrical strikes and provide a lifetime expiry indicator.

Abstract: A method of monitoring abnormality of a clock driver in an electronic apparatus having a clock supply unit that supplies a clock signal and a plurality of function executing units to which the clock signal is inputted for executing prescribed functions at an identical clock, wherein each function executing unit is provided with a clock driver which, on the basis of the clock signal, oscillates internally to reproduce a clock signal, includes monitoring cut-off of an input clock signal and cut-off of an output clock signal of the clock driver, and outputting an alarm upon judging that the clock driver is abnormal in a case where the output clock signal has been cut off but the input clock signal has not.

Abstract: The present invention provides a low burden visual POWER ON indicator for a self-powered electrical circuit protection device. The visual indicator includes a current transformer for producing an induced current in direct proportion to the current supplied to an electrical device protected by the protection device. The induced current is summed and rectified. An energy accumulator stores a predetermined voltage required to operate the protection device. The stored voltage is controlled by an accumulation switch which in turn is controlled by a hysteresis control circuit. The hysteresis control circuit includes an operational amplifier which is biased by a stable reference voltage. When the voltage on the energy accumulator is equal to the stable reference voltage the operational amplifier produces a HIGH output signal. When the voltage on the energy accumulator is less than the stable reference voltage the operational amplifier produces a LOW output signal.

Abstract: The present invention provides a transient event detector for use in a nonintrusive electrical load monitoring system at a monitored site having at least one electrical load. The transient event detector includes a data acquisition portion for acquiring and storing start-up power transient pattern data associated with each electrical load being monitored; a monitor for continuously monitoring total power load pattern data at the site; and a processor for correlating the transient pattern data to the total power load pattern data in order to identify each electrical load.

Abstract: An electromagnetic disturbance power (EDP) checker measures disturbance waves of an equipment under test (EUT), that is, a small electric appliance having a power cord. The EDP checker is capable of detecting and measuring disturbance waves even in sites more confined and having more external disturbance waves than in absorbing clamp method. The EDP checker includes a VHF current probe 2, a matching circuit 3 having input impedance matched at a reception frequency of a measuring equipment (receiver) 6 connected to the VHF current probe 2, and a circuit separating mains 4 for designating terminal impedance of the matching circuit 3 and eliminating influence of power source impedance. Power is supplied from the circuit separating mains 4 to drive the EUT 5 connected to the VHF current probe 2. The maximum value of disturbance power generated by the EUT 5 and supplied through the power cord 12 is measured by the measuring equipment 6 connected to the VHF current probe 2.

Abstract: A detector for detecting electrostatic discharge events in an electronic component, assembly or system and including a display element which produces an immediate indication on exposure to a change in voltage level, an electrostatic discharge sensor, and circuit means for connecting said sensor to said display element. In one embodiment, the detector and the board or other device to be monitored are mounted in a housing having a visual access window with the display element of the detector viewable through the access window and with the detector positioned at the electronic device being monitored.

Abstract: A detector for detecting electrostatic discharge events in an electronic component, assembly or system and including a display element which produces an immediate indication on exposure to a change in voltage level, an electrostatic discharge sensor, and circuit means for connecting said sensor to said display element. In one embodiment, the detector and the board or other device to be monitored are mounted in a housing having a visual access window with the display element of the detector viewable through the access window and with the detector positioned at the electronic device being monitored.

Abstract: An inductive amplifier for identifying and tracing wires is provided with a pair of threaded post terminals for being engaged by the electrical clips of a jumper wire or telecommunications butt set. The inductive amplifier includes a built-in speaker and a depressible power switch for applying power from a battery to a tone amplifier. A switching transistor couples the battery to the tone amplifier whenever a low impedance path is formed between the pair of threaded post terminals, even if the power switch is not depressed. The built-in speaker is connected in series with the threaded post terminals and is a.c. coupled to the tone amplifier for sounding the tone through either the built-in speaker or through a butt set engaged with the threaded post terminals. The impedance of the built-in speaker is selected to be less than that of the butt set for silencing the built-in speaker when the butt set is connected.

Abstract: A workstation mat used to monitor radio frequency, electromagnetic field induced currents flowing through the body of a person standing on the workstation mat. The workstation mat includes an upper and lower conductive plate residing in parallel planes. The upper plate is superposed in spaced apart relation over the lower plate. The mat also includes an electronic circuit coupled to the conductive plates. The electronic circuit senses the induced current flowing through a person's body and sounds an alarm to warn the worker when the induced body current meets or exceeds a predetermined current threshold. The threshold setting is variable and preset by the user. The workstation mat has a reset button switch mounted on one lateral side and contains connectors for a remote alarm and a remote reset switch.

Abstract: A combined current and voltage transformer for a metal-enclosed, gas-insulated high-voltage switching station. It has a current and voltage sensor (10) and a signal processing device connected following the current and voltage sensor (10). A coil (14) wound in the shape of a torus serves as current sensor, and a hollow cylindrical test electrode (15) serves as voltage sensor. After installation of the current and voltage sensor (10) in the metal enclosure (4), the coil (14) and test electrode (15) concentrically surround a conductor (5) of the switching station. This combined current and voltage transformer is cost effective in production, has small dimensions, and a high measurement accuracy.

Abstract: A high-amperage current sensor is disclosed which is suitable for use in an automotive electrical system and which is operatively unaffected by changes in ambient temperature. The current sensor utilizes a shunt assembly having at least one low-resistance shunt element connectable in line between a source of electrical energy and a load. Circuitry preferably configured on an application specific integrated circuit measures voltage drop across the shunt element due to current flow. As a result, an output signal is produced which may be fed to external circuitry for further processing. In presently preferred embodiments, the sensor may comprise analog circuitry producing an analog output signal and/or digital circuitry producing a digital output signal.

Abstract: A system is disclosed for monitoring the operation of an encoder having a scale which is illuminated from a light source, in which light from the scale is detected by a detector, with the encoder having means coupled to the detector for detecting in-phase and quadrature signals representing scale position, means for detecting the phase difference between the in-phase and quadrature signals, and means responsive to the detected phase difference for adjusting the output of the light source to maintain its output at a predetermined level and for providing an error signal representing the amount of adjustment of the output of the light source.

Abstract: A detector for detecting electrostatic discharge events in an electronic component, assembly or system and including a display element which produces an immediate indication on exposure to a change in voltage level, an electrostatic discharge sensor, and circuit means for connecting said sensor to said display element. In one embodiment, the detector and the board or other device to be monitored are mounted in a housing having a visual access window with the display element of the detector viewable through the access window and with the detector positioned at the electronic device being monitored.

Abstract: A microcomputer that reduces through current of output buffers, and thus, reduces power line fluctuation that occurs when a large number of the bus lines connected to output buffers change state at the same time. The through current (or punch-through current) is reduced through the use of a detector circuit that detects the number of bus lines which are changing state and a decoder circuit that changes the impedance of output buffers, which drive the bus lines to external components, when the number of bus lines changing state at a given time exceeds a predetermined number.

Abstract: A system is provided for monitoring signals from a linear or rotary encoder or scale to provide a warning of a malfunction of the encoder or to be able to predict a future malfunction. The system includes a feedback circuit for comparing the output of the detector in the encoder with a voltage reference and for either raising or lowering the voltage to the light source for maintaining constant maximum detected light amplitude regardless of dirt build-up on the scale with the amount of voltage correction to the light source being an indicator of the level of functioning of the encoder. The system also assures constant amplitude output signals from reflectance-type encoders in which the light source and detector are on the same side of the scale and in which the subject servo system maintains a constant amplitude reflected beam.