Abstract: In a computer system accessible via a keyboard--in which the keyboard and system are supposed to reset automatically in reaction to power outages or other disturbances lasting for longer than a first period of time, in which the keyboard and system are generally unaffected by power outages or other disturbances lasting for less than a second period of time less than said first period, and in which lockouts can occur during system power outages or other disturbances lasting for a time greater than said second period and less than said first period--an anti-lockout circuit is interposed between a DC low voltage output port of the system and a DC voltage input port of the keyboard. This circuit is powered by the low DC voltage appearing at said output port and operates in response to small changes in that voltage to switchably interrupt transfer of that voltage to the keyboard input port.

Abstract: A first voltage is first applied to the electrode or electrodes of an electrostatic chuck for electrostatically attracting a workpiece such as a silicon wafer. Then, before the workpiece is removed from the electrostatic chuck, a second voltage which is of opposite polarity to the first voltage is applied to the electrostatic chuck for eliminating a residual attractive force from the electrostatic chuck. The second voltage has a voltage value which is 1.5 to 2 times higher than the voltage value of the first voltage. The second voltage is continuously applied for a period of time which is in inverse proportion to the voltage value of the second voltage.

Abstract: A multi-pole group-operated switch configuration is provided for electrical distribution circuits. The switch configuration includes integral arrangements for sensing circuit parameters and supplying power for a switch operator of the switch configuration. The switch configuration includes a plurality of switch-pole units. In accordance with desired characteristics and features, one or more of the switch-pole units includes an integral current-sensing device, an integral voltage-sensing device, or an integral combination voltage and current-sensing device. The voltage-sensing device also provides operating power to power a switch operator and charge the batteries of the switch configuration.

Abstract: A safety device for vehicle occupants has an operational voltage source, typically the vehicle's battery, and a storage device for electrical energy, typically a capacitor. Several tripping devices, typically ignition tablets, are coupled to the storage device and/or the operational voltage source, for actuating inertial restraining devices, such as airbags, belt tighteners or the like. If the storage device fails, each tripping device is connected for a specified period of time to the operational voltage source by a respective switch. Each switch is triggered by an evaluating device. Therefore, if the storage device fails, as long as the operational voltage source is connected to the safety device, each tripping device and, therefore, inertial restraining device can be actuated.

Abstract: A dual resistance connector system is provided to allow the replacement of power regulators in a computer system without removing power from the operating voltage bus. The new power regulator can be "hot plugged" into the voltage bus without creating a voltage drop on the bus which could lead to voltage transients and logic errors. The low resistance bus bar is augmented by a retractable high resistance contact. The high resistance contact is configured to make electrical connection with the operating voltage bus before the low resistance contact. The establishment of a high resistance circuit allows charging of output filter capacitors without creating a large voltage drop on the operating voltage bus. As installation continues, the low resistance bus bar makes contact and is held in position by a fastener. The fastener is initially held out of electrical contact by a compression spring.

Abstract: A power supply which automatically adapts to different input power sources. A double pole, double throw, latching relay switches the primaries of the rectifier transformer to a series or to a parallel configuration depending upon the output voltage of the rectifier, thus adapting the circuit to either a nominal 220 VAC source or a nominal 120 VAC source. The control circuit also derives power from the rectifier transformer and is designed to operate even under the worst possible undervoltage or overvoltage conditions. The additional choice of 24 VDC power is available by the use of a diode OR circuit. When a 24 VDC source is connected to the DC input, it is also connected to the rectifier output through a diode, so that power is furnished to the load by whichever source has the higher voltage. In this configuration, a battery pack can be connected to the DC input to supply automatic backup power.

Abstract: A fluctuating voltage to be monitored is fed to the non-inverting input of a first op amp via a first input resistor; a reference voltage is fed to the inverting input of the second op amp via a second input resistor. The inverting input of the first op amp is taken from a first voltage divider connected between the reference voltage and ground; the non-inverting input of the second op amp is taken from a second voltage divider connected between the fluctuating voltage and ground. The power inputs of both op amps are connected to a positive voltage and ground. The output of both op amps is tied together, with a first feedback loop feeding the tied output voltage to the non-inverting input of the first op amp via a first high-resistance gain-setting resistor, and a second feedback loop feeding the tied output voltage to the inverting input of the second op amp via a second high-resistance gain-setting resistor.

Abstract: An automatic switching apparatus is disclosed for a system employing a battery and a charging device. A load is automatically disconnected in response to the decrease in voltage caused by an inactivation of the charging device so that the battery will not be undesirably discharges if the load is not turned off. An override switch is provided to allow the load to draw power even when the charging device is not operating.

Abstract: A self contained sensor module mounted on a power transmission line. The module is capable of measuring various parameters such as line current, voltage, conductor temperature, and ambient temperature. The parameter values are processed by sensor electronics which digitize and transmit the values to a ground receiver. The sensor module normally derives its power through electromagnetic induction resulting from current flowing through the transmission line. The module contains a power back-up system, including a battery, which allows sensor operation with minimum current and zero current in the transmission line. The battery is float charged while the sensor is mounted on the transmission line using excess energy derived through electromagnetic induction. When line current drops to a predetermined minimum value, float charging is disabled and the battery supplies power to the sensor module.

Abstract: A new type of power source switching circuit is disclosed. In the device of the present invention, a relay is used instead of semiconductor elements which are used in the conventional types of power source switching circuit. Compared with the conventional ones, the circuit according to the present invention is much simpler, and assures the protection of the circuit against damages due to an overvoltage or impact pulses, which damages are liable to occur in the conventional types of power source switching circuit.

Abstract: A controller for a batter-drive DC motor controls the average motor current by switching a series-connected FET on and off with a pulse-width-modulated gate signal. Motor speed is changed by chaning the duty cycle of the signl, which is generated by an oscillator. An undervoltage protection circuit senses the battery voltage and compares it with a reference system that has hysteresis. An overload protection circuit senses the motor current, integrates the sensed signal, and comprares the result with a Zener reference diode that is connected in an amplifier circuit for positive feedback. The oscillators's pulse-width-modulated output, the undervoltage protection circuits's output, and the overload protection circuit's output are input to a "NOR" Logic gate, whose output drives the gate of the FET.

Abstract: Safety appparatus for sensing an electrically powered device connected to an AC power source to prevent the start-up of the device upon power restoration when the power device is in its "ON" operative condition includes a current sensing circuit that is responsive to reconnection of such a load to prevent the establishment of an electrical circuit path through the device. Included are circuits for sensing the presence of the AC power and for the generation of the sensing current are also presented.

Abstract: A switching module having a plurality of switching channels responsive to a microcontroller for coupling electrical power to a load, and decoupling electrical power in the event an undesired operating condition is sensed. Each switching channel includes a switching transistor and transistor driver. Monitoring circuitry senses the actual voltage drop across the load to provide the controller with an indication of undesired operation. A limiting resistor limits the transistor drive such that the transistor is forced out of satuaration during a high power condition, thereby avoiding undesired power dissipation which would otherwise occur if operation in the saturated condition continued.

Abstract: A reverse battery and loss of positive supply voltage detector circuit includes a power field effect transistor for switching a stored inductive energy to the ground supply voltage terminal if there is a disruption in the power supply. A detector circuit senses a reversal of the supply voltage connections as would happen if the battery were connected backwards and enables the power field effect transistor for discharging a negative voltage that may have developed across an inductive load. The detector circuit further senses a loss of the positive supply voltage and enables the power field effect transistor for discharging a negative voltage that may have developed across an inductive load due to the disruption of applied power.

Abstract: A device for counting the overvoltage surges discharged by a gapless overvoltage arrester contains a sensing head and a counting mechanism which follows the sensing head. In the sensing head, the discharge current carried by the overvoltage arrester in a ground return line during the occurrence of an overvoltage surge is detected. The counting mechanism records an overvoltage surge as soon as the discharge current exceeds a threshold value. During this process, an effective connection between the sensing head and a counter is established for a brief time by means of a switch. This device is intended to be characterized, with a high counting accuracy, by a dead time which is independent of the components used. This is achieved by the measure that the switch is followed by a threshold detector which responds above the threshold value of the discharge current.

Abstract: Disclosed herein are individual sensor modules for mounting directly upon energized electrical power conductors and systems employing such modules, with principal emphasis upon the provision of both data transmitting and receiving means in each sensor module and at an associated ground station. The modules sense the instantaneous values of all parameters necessary to perform complete metering functions and, in one embodiment, are synchronized by a signal transmitted from the ground station and received by all modules so that the values are measured simultaneously on all conductors at a substation. The signals are transmitted by the modules in a time-synchronized manner and are in a condition for use directly by the ground station microprocessor. In another embodiment, data transmissions by a plurality of modules is synchronized to avoid data collisions by self-contained means within each module, requiring no synchronizing signal from the ground station.

Abstract: A power status monitor for an electronic system includes a charge/discharge model of the system power supply. The charge/discharge model contains an estimate of the amount of time during which energy-storage devices in a system DC power supply are capable of maintaining system operation following loss of AC power. The power status monitor monitors the frequency and an amplitude of the voltage of the AC power source for signs indicating imminent failure of the AC power source. In the event that such signs are detected, the estimate in the charge/discharge model is decremented at a rate corresponding to the rate at which charge is consumed. A trip value, applied to the charge/discharge model, determines the time at which a signal is generated enabling an orderly shutdown of the system load. If acceptable AC power is resumed before the trip value is reached, the charge/discharge model increases its estimate of the time available at a rate corresponding to the charge accumulation in the DC power supply.

Abstract: A power supply adapter system is provided which includes a voltage supply source terminal, an output terminal, first and second switches, the first switch being disposed between the voltage supply source terminal and the output terminal, voltage conversion means serially connected with the second switch and disposed between the voltage supply source terminal and a point of reference potential and having an output coupled to the output terminal, and means for detecting first and second ranges of voltages at the power supply source terminal and for producing first and second control voltages, respectively, to control the first and second switches.

Abstract: First and second semiconductor circuits are interconnected by a transmission circuit within an integrated circuit powered by a common voltage supply. The first semiconductor circuit is operative when the voltage applied to the integrated circuit is at a first or a second level different from a ground potential whereas the second semiconductor circuit is operative when the first level is applied and is inoperative when the second level is applied to the integrated circuit. The first semiconductor circuit controls the second semiconductor circuit selectively in test and operative modes as the applied voltage is varied between the first and second levels.

Abstract: A switching control circuit has first and second output terminals, the first output terminal being connected by way of a control resistor to one of a pair of input terminals which, in use of the circuit are connected to an electrical power source, the second output terminal being connected to the other input terminal.

Abstract: A power supply circuit including A.C. input of either 110 volts or 220 volts coupled to a full diode bridge, across the output of which are provided series connected capacitors across which the desired system operating voltage appears. A voltage-controlled current generator for driving a diac and triac is connected between the input supply and the bridge capacitors. At 110 volt input, the current generator closes the triac and the circuitry operates as a voltage doubler to provide the desired system voltage. At 220 volt input, the triac remains open, and the full bridge and capacitors provide the same desired system voltage.

Abstract: A circuit arrangement comprises two feed circuits which are connectible to a load with mutually opposite polarity. The circuit arrangement avoids mechanical contacts in the load circuit, at least with respect to one feed circuit. This is achieved in that switches, provided for the activation at at least one of the feed circuits, are disposed outside of the output circuit and in that a transistor is disposed between such a feed circuit and the load, this transistor being conductive given an activated feed circuit and being inhibited given a deactivated feed circuit. The circuit arrangement can advantageously be employed in remote feed devices of communications transmission device for the purpose of optionally feeding a remote feed section with a remote feed current or with a fault locating voltage.

Abstract: An electronic apparatus including a circuit generating a control signal activating at least one heavy load includes a voltage comparision circuit for comparing a power source proportional voltage with a reference voltage and outputting a power-off signal when the level of the power source proportional voltage is smaller than that of the reference voltage, and a power-off detection circuit responsive to the power-off signal of the comparision circuit for detecting the level of the control signal associated with the at least one heavy load and detecting a power-off condition of the electronic apparatus.

Abstract: A power management system for a recreational vehicle operates automatically to disconnect a major electrical appliance, such as an air conditioner, heater or water heater, from power when the current drawn by additional appliances exceeds a preset current threshold. When the current drawn by these additional appliances falls below the threshold, the major appliance is automatically reconnected. A preferred embodiment of this invention operates to alternate between two or more air conditioners, heaters, or the like, to ensure that only one is connected to power at any given time, but that both are activated alternately and in sequence to provide efficient use of both air conditioners. In addition, preferred embodiments of this invention operate to interrupt operation of the air conditioners whenever the power voltage falls excessively low, and to ensure at least a preselected time delay between the time an air conditioner is stopped and restarted.

Abstract: A photovoltaic panel for converting solar energy into electrical energy output having a voltage and a current and a load requiring a starting current which is higher than a minimum running current. The output of the photovoltaic panel is detected by a sensor and circuitry is responsive to the sensor for applying the output to the load in pulses at a frequency which varies inversely with the maximum available power from the panel.

Abstract: A load control circuit having an input terminal adapted to receive any one of a number of different input voltage signals including signals of at least first and second type. These signals may be, respectively, DC and AC input signals. Control circuits are provided for operation of the load from the input voltage signal. This control circuit includes at least first part responsive only to said input voltage signal being of first type for coupling said signal of first type to the load, and a second part responsive only to the input voltage signal being of second type for coupling the signal of second type to the load.

Abstract: A consumer electronics product such as a portable radio or combination radio/tape recorder having both primary and auxiliary loads is provided with power control apparatus for energizing both loads when connected to a source of a-c potential and energizing only the primary load when connected to a source of d-c potential. The control apparatus includes a solid state switching device in series with the auxiliary load, the switching device coupled to the output of the a-c source such that it is conductive only when a-c electric power is being supplied to drive the loads.

Abstract: A circuit for detecting existence of an information signal comprising an input circuit provided for supply with the information signal, a clamp circuit for clamping a signal obtained from the input circuit to a predetermined fixed DC level, a level detector for detecting the amplitude level of an output of the clamp circuit and for producing a DC output with its level corresponding to the detected amplitude level, and a level comparator for comparing the DC output from the level detector with a predetermined reference voltage to produce an output signal assuming a first level when the DC output is higher than the reference voltage and a second level when the DC output is lower than the reference voltage. The first level or second level of the output signal from the level comparator indicates that the information signal is supplied to the input circuit.

Abstract: A power controller determines which of a plurality of possible input voltages is present and configures a load to operate at that present input voltage.

Abstract: An energization indicator lamp for time switch in which a two-color light emission element which can be switched from either color to the other color is used in place of a conventional energization indicator lamp, and a color of light emitted from the two-color light emission element is automatically switched in response to supply voltage, whereby the presence of energization upon the time switch as well as a value of the supply voltage can easily and correctly be recognized.

Abstract: An electrical control system controls an electrical load device, particularly an inductive load such as the ballast of a gas discharge lamp which generates a back EMF when power is removed therefrom. The control system includes a first electronic switch for controlling the application of power to and withdrawal of power from the load and a second electronic switch which controls the first electronic switch. The second switch is responsive to a command signal preferably occurring between 90.degree. and 180.degree. of the AC power half wave to turn on and thus switch off the first switch which in turn withdraws power from the load. The circuit remains in this state until a predetermined circuit condition occurs at which point the potentials on the load and the AC power supply are at predetermined levels. The equal potential turns the second switch off, whereupon power is reapplied to the load by the first electronic switch.

Abstract: A switching circuit in a power supply for switching between a main power source and a standby power source includes gating device operated at the time failure of the main power source occurs to disable the operation of a plurality of MOSFETs which are switched by high frequency clock signals to couple the main power source to a load. When the main power source returns, the gating device switches the MOSFETs in synchronization with the power signals supplied by the main power source. The circuit includes a transformer operated by the high frequency clock signals to switch the MOSFETs, enabling the transfer of the power signals from the main source to the standby source to occur at the time the main power source fails.

Abstract: A circuit for controlling the power delivered to a load from an alternating current source includes a bridge rectifier coupled to the alternating current source for developing full and half-wave rectified signals in response thereto. The full and half-wave rectified signals are algebraically added to form a reference signal which is applied to one input of a comparator, the other input comprising an adjustable direct current control signal. The output of the comparator comprises a pulse width modulated signal which is used to control the state of a switching transistor connected in series with the load between the rectifier node developing the full-wave rectified signal and a point of reference potential.

Abstract: A safety device for use with an electric appliance to prevent the appliance from inadvertently being started if the appliance is plugged into an outlet when the on/off switch of the appliance is in its on state. A low level sensing current is applied to the appliance before full operating power is applied to the appliance. Detection of the low level sensing current prevents application of full operating power. If no sensing current is detected, full power is applied and the detector is disabled.

Abstract: A circuit for assuring the supply of voltage to an electronic circuit can be switched to an auxiliary voltage source via a series-connected, self-conducting field-effect transistor when the supply source fails. The circuit, which is realized with very little circuitry, has a voltage divider connected across the load; a tap on the voltage divider is connected to the gate electrode of the transistor. The invention is useful, for example, for protecting data in C-MOS memories of microprocessors.

Abstract: Disclosed is a muting circuit, in which the generation of click noise is prevented in that the muting operation is caused to occur at an instant when the instantaneous level (i.e., waveform level) of the input audio signal becomes zero for the first time since the appearance of a muting signal.

Abstract: An electronic switching device is described for use with microprocessors and other memory containing devices. The electronic switching device can be adjusted to provide control signals out to the microprocessor or other memory containing devices when the supply voltage common to all units goes above or falls below predetermined values. The control signals substitute an auxiliary voltage for the supply voltage when wide fluctuations occur. Further, the control signals introduce delays which allow the microprocessor or the memory containing devices to complete an internal processing step before switching in the auxiliary voltage.

Abstract: An electrical connector automatically protected against accidental disconnection. The electrical connector is formed from a plug and a base which are capable of being integrated by a fixation device to provide for the cooperation of contact terminals within insulating bodies each of which has at least one passage for at least one lead for connection to one of the contact terminals. The fixation device is associated with a locking device which is adapted to receive an unlocking order only when a detection device does not detect the presence of any current in at least one of the leads.

Abstract: The present invention is concerned with maintaining the power supply to equipments along at least a section of a transmission line in the event of said line being cut. Each equipment (5) along the line (1) is provided with a local power supply circuit (6,7,9) inserted in the remote power supply loop at the equipment under consideration. A looping impedance (10) is connected in series with the break contacts (11,12) of a controlled switch and parallel across the power supply loop in such a manner as to create a partial power supply loop through the local power supply circuit when the switch is closed. Control means are provided to close the switch in the event of a power failure in the local power supply circuit, and to open the switch again only once the downstream side of the power supply loop draws current above a predetermined threshold value. The above circuit operates for a power supply loop that includes an energy source at one end (E) only of the transmission line.

Abstract: A detector for high-voltage, polyphase gear, having a fuse-switch combination in each phase and a switch operator, includes voltage sensors which provide first time-varying signals indicative of the magnitude and phase orientation of the phase-to-ground voltages on each phase within the gear at the load side of the fuses. The first signals are vectorially added to provide a second time-varying signal, the peak value of which varies as the magnitude and phase orientation of the phase-to-ground voltages of the phases. The second signal is compared to a reference; an error signal is generated when and as long as the phase-to-ground voltages vary beyond set limits. A timer responds to the error signal and provides a third signal a predetermined time after initiation of the error signal, but only if the error signal persists for such time. The third signal is used to cause the operator to open the switches.

Abstract: A power supply having reliable means to detect the failure of an AC power source and to provide an AC fail signal in response thereto includes error-free switchover circuitry to supply emergency power from a standby battery. The power supply comprises a comparator circuit, a Schmitt trigger-inverter circuit, and a feedback circuit which provides positive regeneration to ensure error-free battery switching under AC power fail or restore conditions.

Abstract: A voltage monitoring and indicating circuit for producing an output pulse at an output terminal in response to the loss of a positive dc input voltage at an input terminal. A capacitor is charged during the presence of an input voltage at the input terminal, and a transistor coupled to the capacitor and to the output terminal operates in a non-conducting state so that no voltage pulse is produced by the transistor at the output terminal. In the event of a subsequent loss of the input voltage, the capacitor discharges into the transistor and causes the transistor to operate in a conducting state and a discharge path to be provided through the transistor for the capacitor. As the discharge takes place, an exponentially-decaying pulse is produced by the transistor at the output terminal.

Abstract: A portable power pack for starting and operating automotive engines includes a transformer having a primary winding provided with wires to be plugged into a standard 110 volt 60 hertz electrical supply and a center-tapped secondary winding connected to a pair of silicon controlled half wave rectifiers to provide a direct current output at approximately 16 volts. A remotely operable trigger or gate circuit is provided to cause the silicon controlled rectifiers to fire only at the time it is desired that electrical power be fed to the automotive engine which is to be started or operated. With the exception of the electrical leads from the standard source of alternating current, to the automotive engine, and to the point of remote operation of the trigger circuit, the entire power pack is potted in a solid, thermally stable, thermally conductive material to rapidly dissipate the heat generated within the potted electrical elements of the power pack when it is delivering electrical power to an automotive engine.

Abstract: A home safety unit having an emergency light system for providing light in the event of a power failure or the detection of a fire condition, and a fire detection system for providing an alarm indicating the existence of a fire. The safety unit is designed to have an aesthetically pleasing appearance and to be installed inconspicuously between the base of an existing light fixture and a wall or ceiling. Installation of the safety unit is a simple process, whether installing it when constructing a new building or by retro-fitting it into an existing building.A modified light switch having parallel impedance across the light switch terminals is installed to provide continuous power to the safety unit when the switch is in its off position. Also included is a low voltage dropout system for disconnecting the auxiliary lights when the battery voltage falls below a certain level and for providing an audible alarm indicating this low voltage condition.

Abstract: Sensing apparatus for monitoring the operation of an electrical appliance. The sensing apparatus is plugged into a standard electrical outlet and the appliance to be monitored is plugged into the sensing apparatus. The appliance current flows through a transformer in the sensing apparatus. Detection circuitry including a comparator produces one signal when current flow through the transformer is negligible (appliance off) and another signal when the current flow through the transformer is significant (appliance on). Transistor circuitry connected to the detection circuitry produces a pulse at one output terminal on a transition from the one signal to the other signal from the detection circuitry (appliance turned on) and produces a pulse at another output terminal on a transition from the other signal to the one signal from the detection circuitry (appliance turned off).

Abstract: An electrical power supply for an electronic flash unit with a main capacitor charged by a current flowing from a direct-current source through an electrical power source switch to the main capacitor is disclosed. The electrical power source has a semi-conductor switch connected in the charge path to the main capacitor and a detector, arranged to detect whether or not an aerial discharge is produced between the contacts of said switch upon opening of the electrical power source switch, and, upon occurrence of a discharge, to produce a signal. The semi-conductor switch is opened in response to the signal to stop charging of the main capacitor immediately.

Abstract: A three phase undervoltage monitor separately converts the voltage on each phase to a D.C. voltage, compares each of the separate D.C. voltages with a reference voltage, and operates an output signal whenever one or more of the voltages drops below the reference voltage.

Abstract: An electronic watch control device for manual actuation is disclosed. It comprises a capacitive sensor including a conductive layer on the inner surface of the watch-glass, which is actuated by placing a finger-tip on the outer side of the watch-glass. The sensor is part of a capacitive voltage divider to which a high frequency voltage is applied. Synchroneous detection means are arranged for detecting the high-frequency voltage drop across the sensor in synchronism with the high-frequency. Comparison means are provided for comparing the value of the said voltage drop to a reference voltage and producing a control signal depending on the condition of the sensor.

Abstract: A selection acknowledgment system is disclosed for a laundry appliance having a plurality of function selection switches, a plurality of function indicator lights, and an integrated program chip which controls functions during operation of the laundry appliance. The program chip has a plurality of control lines each of which function as both an input and an output. During an input mode, signals generated by the function selection switches are input via the control lines. In an output mode, the same control lines convey output signals to trigger appropriate function indicator lights. In order to acknowledge operator actuation of one or more of the function selection switches during an input mode, an acknowledgment switching circuit is provided which momentarily turns off all of the function indicator lights as long as one of the function selection switches is depressed, thus indicating to the operator that the function he has selected has been entered into the program portion of the system.

Abstract: Disclosed is a muting circuit, in which the generation of click noise is prevented in that the muting operation is caused to occur at an instant when the instantaneous level (i.e., waveform level) of the input audio signal becomes zero for the first time since the appearance of a muting signal. .Iadd.A muting-off circuit is also disclosed for turning off the muting circuit. .Iaddend.