Abstract: An electronic SPDT switch (1) has, a series FET (9) in a first circuit arm (4) between a common port (2) and a first port (3), a shunt FET (10) in a second circuit arm (6) between the common port (2) and a second port (5), the shunt FET (10) being isolated 90 degrees or 1/4 wavelength from the common port (2), a source applying pull-up voltage to sources of respective FETs (9, 10) and to the common port (2), to provide a connection of the common port (2) with said second port (5), a source applying a first control voltage of opposite logic state to said gates, and the FETs (9, 10) being depletion mode FETs that conduct at a zero sum of said bias voltage and said control voltage, and that conduct when DC power is interrupted, to provide a connection of the common port (2) with the first port (3).

Abstract: A cooling system for cooling components of a computer is provided. The cooling system includes a DC fan which operates at a speed which is substantially proportional to the voltage that is applied to the fan. A zener diode voltage divider is connected in series between a voltage source and a first input of the fan. The second input of the fan is connected to a reference voltage source. A switch is also connected in series between the voltage source and the first voltage input of the fan so as to be connected in parallel with the zener diode voltage divider. When the switch is in a first position, the voltage produced by the voltage source is applied directly to the fan allowing the fan to operate at a first speed. When the switch is in a second position, the voltage from the voltage source is applied to the first input of the fan through the zener diode such that the first input of the fan receives a second voltage that is less than the first voltage thereby causing the fan to operate at a second speed.

Abstract: The positive potential side output of a voltage source (1) is connected to the positive potential side of a first circuit (10) through a terminal (6); the ground (negative potential) side output of voltage source (1) is connected through a terminal (8) to the ground (negative potential) side of first circuit (10). Also, the positive potential side output of voltage source (1) is lowered by a prescribed voltage .DELTA. V by a Schottky barrier diode (2) and is connected to the positive potential side of second circuit (11) through a terminal (7); the ground (negative potential) side output of voltage source (1) is raised by a prescribed voltage .DELTA. V by a Schottky barrier diode (4) and is connected to the ground (negative potential) side of second circuit (11) through a terminal (9). A power supply voltage supplying circuit can thereby be provided wherein latch-up is avoided while still keeping current consumption and electromagnetic interference (EMI) low.

Abstract: The present invention advantageously provides a microprocessor controlled power delivery circuit with short circuit protection. The microprocessor controls the load current flow at the circuit's load connection terminal by connecting this terminal to the positive or negative side of a power supply or opening the circuit to prevent current flow. The short circuit protection uses a passive electrical component feedback circuit to communicate the voltage level at the circuit's load connection terminal back to the microprocessor. The microprocessor routinely monitors this voltage and compares this voltage against the expected voltage at this terminal. When the actual voltage does not match the expected voltage, the circuit will provide protection by interrupting current flow through the load connection terminal.

Abstract: One or more capacitive actuators are controlled by a device that charges the actuators via a capacitor and from a switched mode power supply SMPS that operates according to the flyback converter principle. The secondary coil of the switched mode power supply functions as the charging coil and the discharging coil, i.e., it simultaneously undertakes the function of the large, heavy charging coil. This saves space and weight.

Abstract: A high-current fusible switch includes a nonconductive base, a nonconductive removable top, a plurality of conductive fuse clips, and a fuse having blade-type terminals. The fuse clips are fixedly mounted within the base. The fuse is retained within the top. Switching is accomplished by inserting or removing the top so that the fuse completes or breaks the circuit to which the switch is connected. The switch is connected to the circuit directly at the fuse clips so that a compact design is achieved that eliminates undesirable multiple electrical contacts.

Abstract: An arrangement for controlling the activation of an electrical appliance. The arrangement utilizes a capacitive sensor to recognize the physical proximity of a user (e.g., a hand) to an internal capacitive sensing means. The capacitive change is applied as an input to an electrical control circuit so as to ultimately provide an electrical control signal to an associated electrical appliance. The arrangement does not require direct physical contact to activate any appliance, and may be used to control various power levels associated with a particular electrical appliance (e.g., light intensity for a "dimmer" switch, sound volume for an audio system, activation and trigger signals to an alarm system). The arrangement may be embedded within the wall of a structure (i.e., not visible) and still provide the capacitively-activated control function.

Abstract: The output of the power unit 21 varies on the basis of the output of the power unit 22, and temperature-compensated in accordance with an ambient temperature. The control is performed by the output voltage control circuit 3. The output voltage of the power unit 21 is varied with an output voltage ratio between the outputs of the power units, and by compensating an output voltage of the power unit 22 in accordance with the ambient temperature, the output voltage of the other power unit 21 can be temperature-compensated by the control circuit 3.

Abstract: A circuit for reducing a potential difference between terminals of an open switch. A current source is arranged to supply charges to a capacitor through first and second switches. Charge is being supplied to the capacitor only when the first switch is closed. The current source and the capacitor are maintained at first and second reference potentials, respectively. The circuit further includes a voltage follower which has its output connected to the second switch and one of its inputs connected to the capacitor and the other input connected to its output. The output of the voltage follower is at the same potential as one terminal of the first switch so that when the second switch is closed, the two terminals of the first switch are at the same potentials as each other.

Abstract: A method of cooling computer components is provided. The method comprises positioning the fan adjacent computer components so that the fan is in a position to blow air over the computer components, connecting the fan to a first voltage source through a zener diode voltage divider, connecting the fan to a first voltage source through a switch, manipulating the switch into a first position wherein a first voltage is applied to the fan thereby inducing the fan to operate at a first speed and manipulating the switch into a second position wherein a second voltage is applied to the fan thereby inducing the fan to operate at a second speed which is less than the first speed.

Abstract: A power distribution system in which the loads are connected in series to a current source. At each load, a current source to voltage source convertor provides alternative current paths. A serial power distribution current path includes a modulated switch (e.g. a pulse width modulated switch) to control the amount of power delivered to the load via a load current path. The load current path includes a diode which couples a capacitor across the switch, providing a semi-regulated voltage input to a d.c. to d.c. convertor connected across the capacitor. The d.c. to d.c. convertor provides a regulated output voltage, which is connected to the load. The control circuit for modulating the opening and closing of the switch is connected in parallel across the capacitor.

Abstract: Disclosed is a power supply device for LCD backlight converter in which a Zener diode is placed between an input of power adapter and an input of backlight converter, and a p-type MOSFET is placed between the power adapter and a cell to be used as a switch. When the power adapter provides power, the voltage level of the power is decreased by the Zener diode. When the cell provides power, the power provided to backlight converter is approximately equal to the power stored in the cell. The ratio of the input voltage of power adapter to the input voltage of the cell is decreased to extend supplying period of the cell.

Abstract: A power management system for an implantable device is disclosed. One application is an implantable cardioverter/defibrillator. Charging circuits for implantable cardioverter/defibrillators require relatively large currents from the power supply. The present power management system provides extended device operation and reduced charge cycle time. The present system monitors both current and voltage drawn from the power supply to prevent a loss of system voltage. Elective replacement indication is performed using charging information provided by the present power management system.

Abstract: A high-sensitivity diode temperature sensor includes a reverse-biased diode, such as a Schottky diode, coupled to an adjustable constant current source for biasing the diode into a reverse operating region. The constant current source biases the diode at a particular reverse leakage current that corresponds to a temperature window over which the reverse voltage across the diode exhibits a linear response of several hundred mV/C. The change in reverse voltage can be used as a signal to switch power to an attached electrical load. Also disclosed is a dual-switchpoint temperature controller that incorporates the high-sensitivity diode temperature sensor with a feedback control circuit that enables the controller to switch power to a load at two adjustable setpoints using the single temperature sensor.

Abstract: A safe external A/C adapter protecting the user against hazardous, high-voltage D/C output. High voltage is defined as any voltage in excess of 60V D/C. The adapter provides an internal remote ON/OFF circuit that automatically switches the D/C output OFF unless the output plug is seated within a mating socket disposed in an electronic device powered by the adapter. When the output plug is so seated, the hazardous voltage output is inaccessible to the user. In addition, a secondary shutdown circuit is provided that latches off the A/C input in the unlikely event that the remote ON/OFF circuit should fail. The secondary shutdown circuit is largely independent from the primary remote ON/OFF circuit, and can be implemented using control circuitry already present in the adapter. No special mechanical connectors are required.

Abstract: In a circuit that controls the mean current flowing to a load 40 by turning ON or OFF in predetermined ratio the power source voltage VB applied to load 40 using for this purpose a switch means Sw1, a capacitor C1 is charged with the potential difference generated between the load 40 and power source whilst switch means Sw1 is OFF, and a voltage for control purposes which exceeds power source voltage VB is applied to drive circuit 20 using this stored voltage. A high side switch can thereby be implemented using N type semiconductor elements in a simple circuit.

Abstract: An idle current supplying path is switched during correction operation and during normal operation to detect a magnitude of an idle current flowing through a power amplifying circuit when the correction operation is switched. A bias voltage of the power amplifying circuit is corrected based upon the idle current detecting result. The bias voltage is automatically corrected in such a manner that the magnitude of the idle current flowing through the power amplifying circuit is made coincident with a predetermined current value. As a consequence, the idle current flowing through the respective power amplifying circuit can be continuously maintained to the optimum values respective of to the element deviation.

Abstract: A driving signal generator of the LCD includes a DC/DC converter which generates a constant analog voltage of 5V after receiving a power voltage of 5V or 3.3V. Resistors connected in series between the output terminal of the DC/DC converter and the ground divide the output voltage of the DC/DC converter. An npn-type transistor sets a digital voltage of 3.3V level from the voltage divided by the resistors, and an NMOS transistor outputs the digital voltage set by the npn-type transistor.

Abstract: A semiconductor memory device includes a plurality of external power supply pads P1 to P3. Connection between external power supply pads P1 to P3 and an external power supply is determined in accordance with the voltage of the external power supply to be used, and the connection is switched by bonding. External power supply of a high voltage level is connected to an external power supply pad P2 which is connected to VDC1 and VDC2. A circuit including memory cells operates using the voltage applied from VDC1 or external power supply pad P3, while a group of word line drivers operates using the voltage applied from VDC2 or external power supply pad P1. VDC1 down converts the external power supply voltage, and VDC2 down converts it in accordance with the level of the voltage of the external power supply voltage, and generates internal power supply voltages, respectively. Accordingly, a semiconductor memory device which operates adapted to different external power supplies can be obtained.

Abstract: A method and apparatus for supplying power to a central processing unit (CPU) in computer systems which normally mount CPUs on a motherboard and supplies power to the CPUs via motherboard circuitry which delivers CPU current from power supply sources connected to the motherboard. The method provides the supply of partial or complete power to a CPU mounted on a computer motherboard directly from a power supply and involves the steps (a) disconnecting the power supply to the motherboard; (b) disconnecting the CPU from a CPU socket or plug on the motherboard; (c) mounting the CPU on an adaptor that can be installed in the CPU socket or plug on the motherboard; (d) installing the adaptor and the mounted CPU in the CPU socket or plug on the motherboard; (e) attaching the power supply to the adaptor to provide partial or complete power to the CPU; and, (f) attaching the power supply to the motherboard.

Abstract: A non-rotating portable voltage sag generator includes for each phase a pair of cascaded standard industrial auto-transformers each having, for example, six taps and when they are cascaded the final output voltage of each phase is a product of the per unit value of each individual auto-transformer. Closed transition switching is provided to switch the auto-transformer into and out of the circuit effectively only during the time a voltage sag is desired. All of the switches and auto-transformers are conveniently carried in a single portable enclosure. There are no moving parts or diesel engines; thus, the non-rotating sag generator is useable in any part of an industrial plant.

Abstract: An isolation circuit for use in a power plant having a first power supply that powers a first load and a second power supply that powers a second load. The first and second power supplies are cross-couplable via a first and second auxiliary path to allow the first power supply to power the second load and the second power supply to power the first load. The first power supply is subject to a reverse current by way of the first auxiliary path. The isolation circuit includes a first switch, located in the first auxiliary path, that substantially reduces the reverse current flowing into the first power supply thereby enhancing an isolation of the first power supply. A controller is, also, provided that monitors the first switch thereby enhancing a reliability of the power plant.

Abstract: A circuit for the controlled recycle without oscillation of a discharge current from an inductive load. The circuit comprises an active element connected, in series with the inductive load, between first and second power supply terminals, and having a control terminal to which a driver circuit is connected. The circuit further includes a recycling regulating circuitry connected to a connection node between the active element and the inductive load, and sensitive to a voltage threshold at the connection node to generate, depending on attainment of that threshold, a power-on signal for application to the control terminal effective to start up recycling of the discharge current through the active element. The circuit further comprises a control circuit for controlling the voltage oscillation at the connection node at the end of the recycling.

Abstract: A power-on-reset (POR) circuit having a reduced sized charging capacitor is described which includes a voltage detection portion, a delay portion, and a POR signal generation portion. The voltage level detection portion functions to provide a level indicator signal after the power supply has reached a predetermined voltage level. The delay portion in response to the level indicator signal indicating that the power supply is greater than or equal to the predetermined voltage level charges a chargeable node to an inverter trip point voltage level in a predetermined delay time interval dependent on a capacitive element and a diode connected MOS device both connected to the chargeable node. The POR signal generation portion, in response to the voltage trip point level on the chargeable node, outputs a POR signal an extended time interval afterwards.

Abstract: The present invention relates to a high-frequency switching circuit, and provides a high-frequency switching circuit capable of withstanding high output power, achieving highly efficient isolation, and reducing an insertion loss using inexpensive pin diodes. A switching control voltage or ground voltage developed at one power supply is applied to a control terminal. A diode resonant circuit includes a diode that applies a signal to an output terminal through an anode thereof and a signal to an input terminal through a cathode thereof, and has a resonant circuit, which attains a parallel resonance owing to a parasitic capacitance formed when the diode is off in the frequency band of the high-frequency signal, interposed between the anode and cathode of the diode. A first bias circuit separates a switching control current stemming from the switching control voltage applied to the control terminal from the high-frequency signal and supplies the switching control current to the anode of the diode.

Abstract: A printed circuit board includes an edge connector operable to be coupled to an expansion bus. An integrated circuit is mounted on the printed circuit board and is coupled to the edge connector. The integrated circuit is operable to snoop memory operations on the expansion bus and cause selected memory data to be stored in a memory on the printed circuit board. A first power conductor extends across a first portion of the printed circuit board and is coupled to the integrated circuit. A second power conductor extends across a second portion of the printed circuit board and is also coupled to the integrated circuit. The circuit board also includes a decoupling unit connected between the first power conductor and the second power conductor. The decoupling unit causes disconnect of the first power conductor from the second power conductor during times in which voltage within the first power conductor is less than voltage within the second power conductor.

Abstract: A lift pin 95 for dechucking a substrate 15 held to a chuck 50 by residual electrostatic charge, the substrate being processed in a plasma formed using RF currents, is described. The lift pin 95 comprises (a) a movable elongated member 110 having a tip 115 suitable for lifting and lowering the substrate 15 off the chuck 50, and capable of forming an electrically conductive path between the substrate 15 and a current sink 105. The electrically conductive path comprises at least one of the following: (1) a frequency selective filter capable of filtering RF currents flowing therethrough so that substantially no RF currents flow through the filter; or (2) a resistor having a resistance sufficiently elevated to reduce the voltage caused by RF currents flowing therethrough, by at least about 50%.

Abstract: A pull chain switch circuit device for a stepless control of brightness of lighting fixtures of a ceiling fan is composed of a central control unit, a voltage stabilizing and rectifying unit, a pull chain switch, a protective unit, a zero crossing loop, and a gate unit. The input end of the voltage stabilizing and rectifying unit is connected with an alternating current source, whereas the output end of the voltage stabilizing and rectifying unit is connected with the central control unit. The pull chain switch has one end connected with the output end of the voltage stabilizing and rectifying unit. The protective unit is connected with the alternating current source and the central control unit. The zero crossing loop is connected with the alternating current source and the central control unit for detecting a time point at which the alternating current source becomes 0V.

Abstract: In a multi-cell battery, an open-circuit failure of any one cell renders the entire battery unusable. An automatic electronic bypass switch is connected across each battery cell to provide a low-resistance conductive path around such battery cell should it fail. Contrary to conventional usage in which a fuse is employed to "clear" or "open" a short-circuit condition, the electronic switch of the present invention employs a fuse to activate a highly conductive path, which ideally would approach a short circuit, around an open-circuit condition. The electronic switch includes a field-effect transistor connected across the battery cell and a fuse to hold the field-effect transistor in the "off" condition.

Abstract: A wakeup generator for generating an interrupt pulse to a microcontroller (10) of an electronics module in response to a switch position change of a multi-position resistance ladder switch (14) to awaken the microcontroller (10) from a low power sleep mode. The wakeup generator uses a low current constant current source (18) and a detector(12). The low current constant current source (18) provides sense current for the switch (14) with a voltage developing across the switch varying according to the switch position selected with each switch position developing a different voltage. The detector detects a change in the voltage across the switch due to a switch position change and generates the interrupt pulse to the microcontroller.

Abstract: A control device for a fluorescent lamp comprises two independent circuits based on a power transistor and a switching control circuit, series-connected between a high voltage and the ground. The power transistor has a diode that is reverse mounted between its two electrodes. The switching control circuit comprises a circuit for the detection of a voltage at the terminals of the diode greater than a voltage reference value and a circuit for the detection of the integral of the current flowing in the transistor that is greater than a current reference value corresponding power of the lamp.

Abstract: A hot stand-by switching unit for a receiving apparatus including regular and a protection receiver comprises a branch circuit and a control circuit. The branch circuit consists of a coupler and a high-frequency switching unit. The high-frequency switching unit is controlled by the control circuit and supplies a low loss output of the coupler to the regular receiver and a high loss output of the coupler to the protection receiver. When the regular receiver breaks down, the high-frequency switching unit supplies the low loss output of the coupler to the protection receiver and the high loss output of the coupler to the regular receiver.

Abstract: In this system including a switching device (21) interposed between an information processing unit (22) and an analogue switch (23), in which the unit includes an analogue information input (24) and a wake-up information input (25) originating from an output of the switch, the unit includes a stand-by/wake-up state control output (27) for the device, and this device includes a switch facility (28) openable by the state control output, and which is interposed between the output of the switch and a comparator (29) adapted so as to compare the output from the switch with a reference level so as to deliver a corresponding command at the wake-up information input, and a switch facility (30) closeable by the state control output, and which is interposed between the output of the switch and the analogue information input (24).

Abstract: An improved power supply apparatus for controlling electrical elements of a vehicle which is used for a vehicle using 12 volts as well as a vehicle using 24 volts. The apparatus includes a mode selection switching unit which is selectively switched in accordance with a voltage level inputted from a battery, a first voltage transformation unit, which is not operable when the mode selection switching unit is in the turned-on mode and is operable when the mode selection switching is in the turned-of mode, for dropping an input voltage from the battery to a predetermined level, and a second voltage transformation unit for dropping a voltage from the battery when the mode selection switching unit is in the turned-on mode and dropping an output voltage from the first voltage transformation unit to a predetermined level when the mode selection switching unit in the turned-off mode.

Abstract: An analog circuit controller having fewer signal paths and elements is disclosed herein. A microcomputer has a first D/A converter for generating control voltages variable into a plurality of levels in a time-divided manner and a second D/A converter for generating switching signals of various levels each indicative of the type of a control voltage. The analog circuit controller receives the outputs of the first and second D/A converters and responds to the output of the second D/A converter to select the necessary circuit to be controlled to which the control voltage is to be applied. As a result, a plurality of circuits to be controlled can be controlled through only two signal lines.

Abstract: A circuit isolator apparatus for use with pump or master valve circuits having a plurality of controllers connected thereto. One isolator apparatus is used in association with each controller. The isolator apparatus includes a pair of relays which allow only one controller to access the pump or valve circuit at a time to prevent feedback between controllers and damage to controllers due to incorrect phasing.

Abstract: An apparatus for sensing the presence of an auxiliary battery connected to a cellular telephone is disclosed. An internal battery and a removable auxiliary battery are connected to the power system of the cellular telephone through first and second switches respectively. Connection of the auxiliary battery creates a current flow that is detected by a current sensing circuit which generates a current signal indicating the detection of current flow. A voltage sensing circuit determines whether the auxiliary battery can provide a predetermined voltage level and generates a voltage signal indicating the results of this test. A processor then utilizes the signals from the voltage sensing circuit and the current sensing circuit to control the pair of switches to connect the main and auxiliary batteries to the power circuitry of the cellular telephone.

Abstract: A branching unit for an underwater communications system is arranged so as to provide remote hot switching for electrical power. The unit has three terminations (1, 2, 3) each for a different one of three line cables and one or more power demand circuits (20) requiring an electrical power feed from the line cables. A first switch is actuable to complete a current path between an appropriate pair of the three terminations via one or more of the power demand circuits depending upon relative line voltage. A second switch is actuable after actuation of the first switch depending upon current supplied to the power demand circuit(s) rising above that which occurs upon action of the first switch. The second switch completes a circuit between the non-paired termination and a fourth termination for a sea-earth.

Abstract: A recording apparatus capable of being connected to plural kinds of recording devices alternatively, comprising: connecting unit for connecting the plural kinds of recording devices alternatively; battery for supplying electrical energy to the connected recording device via the connecting unit; memory unit for storing a plurality of minimum potential values each of which is necessary for operating each of the plurality of recording devices; comparing unit for comparing the potential of the battery to be provided against each of the plurality of minimum potential values; and notification unit for notifying usable recording device or devices for recording out of the plural kinds of recording devices or devices on the basis of a comparison result by the comparing unit.

Abstract: An AC load switching system predicts when a zero voltage cross-over condition will exist for purposes of switching an AC load to minimize inrush currents. Prediction is carried out by characterizing the switching devices, which preferably are electromechanical in nature, and determining closure and bounce delays associated with each type of switching device. The system includes a processor, which could be a programmed microprocessor. The processor stores characterization parameters for the load switching elements including closure delay time as well as bounce time intervals. The processor energizes a switching element to close same at a time during the AC line cycle such that when the delay interval has passed and one half of the bounce interval has passed, the line voltage will be at a cross-over or zero voltage condition thereby resulting in minimal inrush current when the contacts have completely closed.

Abstract: A very low cost method of driving the coil of a meter disconnect switch utilizes the 60 Hz signals from an existing power supply rectifier to generate properly phased gate drive signals to SCRS, with only one stage of isolation.

Abstract: A voltage-suppressed voltage source which uses switching devices to maintain a high performance, stable DC voltage by suppressing unstable DC voltages and providing a stable supply of power to a load. The voltage source has a partial resonance circuit for reducing power consumed while a switching device in the voltage source turns `on` and `off`.When a first switching device is off, unsuppressed DC voltages are stored in a resonance capacitor. When the first switching device is turned on, a resonance current flows from the resonance capacitor through a resonance coil and a second switching device just before the first switching device is turned on. This resonance current also induces a suppression effect to the output voltage, and allows the voltage suppressing portion to pass a current in the same direction as when the first switching device is on.

Abstract: A device for controlling a switching relay to deliver power to a load. The switching relay selectively couples a hot leg of a utility power supply to the load. The load is coupled to a neutral wire of the utility power supply. The device includes a sensor for detecting whether an area is occupied. If the sensor indicates that the area is occupied and the load is powered off, the device monitors the line voltage for a zero crossing. Upon detecting a zero crossing, an amount of time to a subsequent zero crossing is measured and stored. Then, the device waits the amount of time between zero crossings, less a delay time for closing the contacts of the relay, and initiates a closing of the contacts of the relay. Similarly, when the sensor detects that the area has not been occupied for a predetermined amount of time and the load is powered on, the line voltage is monitored for a zero crossing and a time to a subsequent zero crossing is measured and stored.

Abstract: Method and apparatus for providing alternate current paths to a junction through different sets of gate controlled SCRs coupled to the junction. The method starts with the step of initiating a switch from an active set of SCRs to an inactive set by removing a gate signal from two parallel connected, opposite sense current carrying SCRs which in combination carry AC current in either direction. Removal of the gating signal is often initiated, for example, in response to an indication that one alternating current source is faulty so that a switch to a second source is initiated. Current is then sensed through the two SCRs of the active set to determine a current carrying state for each of those two SCRs. After the state of the current carrying SCRs is determined the current carrying state of the SCRs is confirmed during a delay time period.

Abstract: A power supply circuit prevents, without the use of a series diode, the flow of reverse current from a battery to an AC power adaptor when the power adaptor is disconnected from its external power source. The circuit includes both voltage and current detectors to determine if the output voltage and current of the power adaptor are above or below predetermined reference levels. A summing circuit sums the outputs of the voltage and current detectors, and when both the detected voltage and current are below the reference levels, a switch disconnects the battery from the output terminal of the power adaptor, thereby preventing reverse current flow.

Abstract: A circuit is provided for energizing one or more discharge lamps. The circuit is capable of being powered from one or two alternative AC voltage and comprises a transformer having a common first tap, a second tap and a third tap, and a dual voltage means which accepts power from a pair of AC source lines. The dual voltage circuit connects the AC source lines to either the first common first tap and the second tap, if the voltage is at the first AC voltage, or to the common tap and the third tap if the voltage is at the second AC voltage.

Abstract: A low voltage battery pack monitoring circuit for a battery powered electronic device is disclosed. The circuit utilizes low battery and power failure set point voltages and first and second comparison circuits to compare voltage across the device battery pack to the set point voltages. If the battery pack output voltage falls below the low battery pack set point voltages, the first comparison circuit sends a signal to a microprocessor causing a low battery indicator light to be actuated. If the battery pack output voltage continues to decrease below the power failure set point voltage, the second comparison circuit includes a comparator which changes output state and turns off selected electronic systems of the device and the device enters a suspend mode. The low battery pack set point voltage value and the power failure set point voltage value are determined using an empirical look up table.

Abstract: A method and apparatus for receiving, monitoring and characterizing network power information in real time through the use of a specialized display system. A processor receives three phase current and voltage information from a network power relay, converts and scales that data into a two-dimensional vector having coordinates that are represented by, and displayed as, a single pixel on a display screen. The repeated monitoring provides a Feature Map (FM) of the network system that can be easily read and understood by operating personnel.

Abstract: A selector switch circuit comprises an input terminal to receive a positive voltage, an input terminal to receive a negative voltage, a command input terminal to receive a first command logic signal and an output terminal to provide an output voltage. The output is connected selectively to one of the input terminals, the first and second input terminals being connected to the output terminal by means of a first transistor and a second transistor and the circuit comprising control means for the production, as a function of the command signal, of the control voltages applied to the control gates of the transistors for the selective connection of the output terminal to one of the input terminals.

Abstract: A communication system is presented whereby sequences of video screens sent from a host CPU to a video controller can be stored and subsequently retrieved by a terminal located remote from the host CPU. Detection logic, controller memory, processor and a communication unit are compiled as a system configured upon a PCB. The PCB is configured to maintain certain vital functions even if power supplied from an expansion bus ceases. The PCB may employ a battery which maintains processor and controller memory activities and communication therebetween for a period of time sufficient to sustain video screen information stored within the controller memory. Thus, decoupling circuitry is present which prevents drain upon the battery if the communication unit is not being used. The decoupling unit separates power and signal conductors between portions of the printed circuit board.