Abstract: An uninterruptible power supply which is advantageous for use with a computer receives power alternatively from a utility main power source or a rechargeable battery. The uninterruptible power supply includes an input for receiving AC utility power, an AC to DC converter coupled to the input, receiving AC power from the input, having at least one regulated D.C. output, and generating DC power at an output of the converter, a transformer having a primary winding and a secondary winding, an inverter coupled between the AC to DC converter and the primary winding of the transformer and arranged to supply a chopped DC voltage to the primary winding to cause a corresponding chopped DC voltage having an amplitude V.sub.s to be generated across a secondary winding of the transformer coupled to the output, an auxiliary power supply having an energy store having a supply terminal that is operable at a voltage V.sub.

Abstract: A power supply circuit is provided with a supplemental power source which is intermittently brought into service each time a main power source is coupled to a high power drain circuit. That is, the supplemental power source is switched to a circuit, which is susceptible to power drop, in response to switching over of the main power source to the high power drain circuit.

Abstract: A power supply switching apparatus for electronic equipment including a first control circuit connected to a battery. The first control circuit monitors a power supply voltage of the battery to output a first control signal when the power supply voltage of the battery is lower than a first predetermined voltage. The first control circuit also outputs a second control signal when the power supply voltage of the battery is higher than a second predetermined voltage. A second control circuit monitors whether power is supplied from an external power supply to the electronic equipment, to generate a third control signal when the power is not supplied from the external power supply. The second control circuit generates the third control signal regardless of whether the second control signal is present, when power is supllied from the external power supply. A switching circiut section supplies power from the battery to the internal circuit when the first and third control signals are not present.

Abstract: A power transfer system includes four relays for switching power from a primary power supply to an auxiliary power supply having a starter motor and a kill switch. A first relay couples the primary power supply to the load. A second relay is responsive to the failure of the primary power supply and activates the starter motor and deactivates the kill switch. A third relay is responsive to power supplied by the auxiliary power supply and couples the auxiliary power supply to the load. A fourth relay is responsive to power supplied by the auxiliary power supply and decouples the primary power supply from the load and deactivates the starter. An optional time delay relay is provided for delaying the activation of the starter motor upon the loss of power supplied by the primary power supply.

Abstract: The present invention relates to a circuit for integrating a local switch and a remote-control switch, primarily comprising a remote-control circuit, a first trigger circuit, a second trigger circuit, an integrating unit and a power circuit, in which the integrating unit further comprises two timer circuits, a local switch detecting circuit, a switching circuit and a power supplement circuit. When the circuit described above is in an initial state, in the event of the local switch does not operate within a certain time period, the control priority belongs to the remote-control circuit. When a user controls a load by remote control, the remote-control circuit will send a signal to reset the local switch detecting circuit and to make the output signal of the remote-control circuit be the control source of the switching circuit directly.

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 power supply for maximizing the life of batteries such as but not limited to 12 volt DC batteries. Two batteries are preferably used. A timer is connected to the first battery output terminals. The timer regulates when a DC motor is turned on and off. The motor is connected to alternator connected to an output of the DC motor. The second battery is connected to and receives a charge from the alternator. An invertor outputs 115 volts at approximately 800 to approximately 1500 watts at 60HZ. The invention allows the first battery and the second battery to have an increased lifespan compared to being used separately. Embodiments for using the invention include computer set-ups, electrical golf carts, electrical car, medical devices, emergency backup power supply, and a portable canister supported container.

Abstract: In a recording apparatus such as an ink jet type recording apparatus, there are provided a recording unit for performing a recording operation on a recording material in response to a recording signal, the recording unit having a power supply for supplying power to drive the same, and a feeding unit for automatically feeding the recording material to the recording unit. This feeding unit is detachably connected to the recording unit. The recording apparatus further comprises a power supply apparatus installed on the feeding unit, capable of supplying power to the recording unit under such a condition that the feeding unit is connected to the recording unit. The recording unit can be made compact and lightweight. The recording unit is solely operable as a portable recording unit.

Abstract: According to the present invention, an emergency power supply to be coupled to an electric power source providing an incoming AC signal may include an input/output terminal, a battery with a DC voltage, a rectifier coupled directly to the input/output terminal and connected to the battery, an inverter coupled directly to the input/output terminal and connected to the battery, and a control circuit coupled to the rectifier and the inverter so that in a first operational mode the rectifier is coupled to the battery to rectify an incoming AC signal at the input/output terminal to charge the battery and the inverter is decoupled from the battery, and in a second operational mode the inverter is coupled to the battery to invert the DC voltage to provide an outgoing AC signal at the input/output terminal and the rectifier is decoupled from the battery.

Abstract: A system-interconnected generator permits effective use of surplus power generated by a solar battery for operating electric equipment such as an air conditioner. The system-interconnected generator having a power converter for converting solar energy to AC power and supplying the AC power to a system on a commercial AC power supply so as to make it possible to sell the power to the system is equipped with: a storing section for storing an integrated value of the AC power which has been converted from solar energy by the power converter; a correcting section for subtracting a value of power, which is consumed by particular electric equipment receiving power supplied from the system, from the integrated value stored in the storing section; and a demanding section for enabling a demanding function of the electric equipment when the integrated value stored in the storing section becomes smaller than a predetermined value.

Abstract: An intelligent battery power system having a main battery and a swap battery including a battery presence detector for detecting whether the main battery is present and a power controller for operating the system in a suspend mode and applying power from the swap battery in a suspend mode when the battery presence detector detects that the main battery has been removed and for interrupting the power from the swap battery with power supplied from the main battery to operate the system in a resume mode when the battery presence detector detects that the main battery is present. The system prevents volatile data from being lost when the battery for a portable computer is removed or becomes detached for any reason.

Abstract: An electronic trip device for a circuit breaker comprising at least one current sensor supplying a current to a first power supply circuit. A distribution line connected to an output of the first power supply circuit distributes an electrical voltage regulated by a first chopping regulator to electronic circuits of the trip device. The trip device comprises a second power supply circuit connected to an external power source and a second chopping regulator connected between the second power supply circuit and the distribution line. The second chopping regulator operates in synchronized manner with the first chopping regulator.

Abstract: An apparatus for energizing a large scale medical imaging system, preferably in the form of a CT scanner so that the scanner operates off an uninterruptable power supply in the event that the external power falls below sufficient power to operate the system so that system operation remains uninterruptable. The system is designed to operate off a broad range and types of external power supplies including those providing DC, single or three phase AC power. The system therefore can operate from a common single phase AC outlet. In addition, power factor correction is provided so that the system can correct for phase differences between the voltage and current at the input line created by the input impedance of the system.

Abstract: A un-interruptible power supply (UPS) apparatus for a diffusion furnace used in semiconductor device fabrication. The diffusion furnace consists of a power electronic subsystem coupled to a three-phase utility power source via two series-connected normally-open main circuit breaker switches, an automatic control unit, and a direct-current power supply. The automatic control unit controls the operation of the diffusion furnace. The UPS apparatus includes a UPS unit having a power input connected to a node between the two series-connected normally-open main circuit breaker switches. A first normally-open circuit breaker has a switch connected between the output of the UPS unit and the power input of the automatic control unit. A second normally-open circuit breaker has a switch connected between a first phase power line of the three-phase utility power source and the input of the direct-current power supply. A third normally-closed circuit breaker has a switch connected to the output of the UPS unit.

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.

Abstract: An uninterruptible power supply control system of for controlling power supply to an internet type apparatus, a CPU type apparatus requiring a shutdown processing and a printer type apparatus not requiring the shutdown processing. The uninterruptible power supply control system comprises an uninterruptible power supply device which is connected to a power source and arranged to be supplied with power from a battery. The uninterruptible power supply device is arranged to output a shutdown signal to the CPU type apparatus when a power service interruption occurs. The CPU type apparatus makes its shutdown processing in response to the shutdown signal. The internet type apparatus is allowed to be directly electrically connected to the battery so that the internet type apparatus is kept in an uninterrupted power supply condition.

Abstract: A semiconductor power module is configured to prevent concentration of load in a certain semiconductor power switching element. A diagnosis circuit (PC) of a module (10a or 10b) compares a sensing signal (SSE) for example, which is sent out from a sensing circuit (Se) and is proportional to the collector current of an IGBT element, with a reference voltage, and judges presence or absence of abnormality in the collector current. If abnormal, a shutdown signal (S.sub.SD) is sent out to a shutdown circuit (SD), and the IGBT element is cut off, and simultaneously an abnormality detection signal (S.sub.F01 or S.sub.F02) is sent out to the other module (10b or 10a). The diagnosis circuit (PC of the module (10b or 10a) receives the abnormality detection signal (S.sub.F01 or S.sub.F02), and sends out the shutdown signal (S.sub.SD) to the shutdown circuit (SD), thereby shutting down the IGBT element. Since the transmission timing of both shutdown signals (S.sub.

Abstract: A surge suppression circuit for gradually charging a capacitance of a device being hot plugged into a system, such as a disk drive being hot plugged into a RAID system. Without reliance on a permanently turned-on series element, such as a pass transistor, the surge suppression circuit uses a trigger circuit in combination with either a current limiting circuit or a slew rate control circuit. The current limiting circuit relies on a current sensing resistor in combination with a transistor that turns on when a voltage reaches a certain level across the current sensing resistor. The slew rate control circuit relies on a feedback mechanism that includes a capacitor and a resistor for maintaining a substantially constant rate of charging the capacitance of the device being hot plugged.

Abstract: A controller, which is normally used for controlling different modes is used for circuit protection. The suipply voltage and control signals from the switched mode power supply to the controller are modified when a short circuit occurs. In response thereto, the controller switches "off" a mode-control signal and the switched mode power supply operates in standby mode.

Abstract: A communications adapter card includes a circuit arrangement for causing an electrical voltage to be supplied to the card from a first voltage source, even if a second voltage source is available, and from the second voltage source if the first voltage source is not available. The circuit arrangement includes a Field Effect Transistor (FET) with its gate electrode connected to a control circuit which puts the FET in an off-state to inhibit the second voltage source from supplying voltage to the card if the first voltage source is available, and puts the FET in an on-state to supply voltage to the card if the first voltage source is not available. The invention makes it possible for a single communications adapter card to be used to attache power managed and non-power managed personal computers (PCs) to a Local Area Network (LAN).

Abstract: A power supply device for an electromotive railcar is adapted to receive external current from an overhead electric line via a pantograph and to feed driving current of lower voltage than the external current to electric loads in the railcar through first and second current output lines. The power supply device is provided with a static inverter couplable to the overhead electric line through first and second input lines and capable of producing the driving current. A battery is connected to the static inverter in parallel with the loads for selectively charging the driving current and discharging the charged electric current to the loads. An anti-discharge switch is provided on the first current output line for selectively connecting and disconnecting the loads to and from the battery.

Abstract: A hybrid vehicle includes a power unit communicating power between a turbine alternator, flywheel and traction motor. The power unit stores DC power in capacitors and places the power on DC bus for use in driving the induction machines. Power transistors receive the DC power from the DC bus and are pulse width modulated to output a synthesized AC wave form at their output. An Ac bus assembly comprises the power transistor modules connected in a plane and each having contact pads formed thereon for providing AC current sources. A bus bar interconnects at least one of the current sources to a peripheral device. The bus bar comprises a plurality of elongated flat plates having a width substantially greater than its thickness and laminated to one another.

Abstract: An excess current detection and control circuit for a power source system to provide an overall electric current to a device to be tested, includes: a plurality of device power sources connected in parallel with each other to form the power source system whereby supplying an electric current to the device wherein each of the device power sources is provided with a predetermined excess current level flowing to the device and maintaining the excess current without further increasing the electric current level and generates an excess current detection signal when the electric current reaching the excess current level, a power source condition monitor device connected to the plurality of device power sources for receiving the excess current detection signal from each of the device power sources and generating an interruption signal only when receiving the excess current detection signal from each and all of the device power sources connected to the device to be tested, and a central processor unit for determining

Abstract: An electrical circuit has a power source line from a battery. The power source line is divided into a primary side and a secondary side by a device, such as, for example, a diode. A high current load circuit is connected to the primary side and a lower current device, such as, for example, a display-related circuit and a capacitor are connected to the secondary side. The display-related circuit continues to receive adequate power when the battery voltage drops due to operation of the high current load circuit. In addition, a voltage detector is connected to the secondary side, where the voltage fluctuates less than on the primary side. The voltage detector controls operation of the high current load circuit. As a result, the high current load circuit can be efficiently driven.

Abstract: An interface cable used for electrically connecting a terminal apparatus to a host apparatus. The host apparatus has an internal power source and a switch for turning on/off the internal power source. A cable means is used for electrically connecting an external power source to the terminal apparatus to supply electrical power from the external power source to the terminal apparatus. The external power source on/off control system includes a switch, such as an electromagnetic relay, incorporated in a module connected to the cable, for detecting the on/off state of the internal power source in the host apparatus and turning on or off the external power source on the basis of the on/off state of the internal power source.

Abstract: A multiplexor having a multiplexor control input terminal for selectively providing one of a plurality of conductor voltage levels to a conductor. The multiplexor includes a first switch, which is coupled to the conductor, for providing a first conductor voltage level to the conductor. A second switch is also included and coupled to the conductor for providing a second conductor voltage level to the conductor. To provide a selective discharge path for the conductor during switching, the multiplexor further includes a third switch coupled to the conductor. A discharge circuit is also provided and coupled to the conductor and the third switch for sensing the voltage level of the conductor to turn on the third switch as necessary at the early stage of switching among conductor voltage levels.

Abstract: In a backup power system capable of deriving power from alternate AC primary and DC backup power sources to provide continuous AC power to an AC load and including an inverter/switch module having DC and AC inputs and an AC output, a maintenance bypass switch for, and method of decoupling the AC primary and DC backup power sources from the backup power module to allow maintenance to be performed thereon.

Abstract: A synchronizing device for a parallel connection of a synchronous generator and an a.c. network. The device includes a measuring circuit for measuring the voltage and frequency of the generator and the a.c. network and for measuring the phase angle between the generator and the a.c. network. The measuring circuit includes control outputs for regulating the rotational speed of the generator drive. A set value for the generator frequency includes a defined slip at the start of balancing. The measuring circuit also regulates the voltage output of the generator to match the a.c. network voltage. Once the phase angle between a.c. network voltage and generator voltage has fallen below a predefined value, null balance occurs.

Abstract: A zero power circuit includes an upper power supply voltage pad, battery pad, a power control circuit, and a suppression circuit. The power control circuit provides power to the zero power circuit by switching between the battery pad and the upper power supply voltage pad. The suppression circuit is connected in series between the power control circuit and the battery pad. The suppression circuit includes a resistor connected in series between the battery pad and the power control circuit, wherein current flowing through the transistor during a latch condition causes the voltage to drop across the resistor, suppressing the latchup condition to the battery pad. The suppression circuit also includes a transistor connected in parallel with the resistor, the transistor having a gate, wherein a first signal applied to the gate turns off the transistor and a second signal applied to the gate turns on the transistor, wherein the resistor is shorted when the transistor is turned on.

Abstract: A failure-free power source device memorizes the history of errors of a commercially available power source, monitors the stability of the power source on the basis of the history, directly outputs, when the power source remains stable for more than a predetermined period of time, an AC input as an AC output, and releases, when an error occurs in the power source, energy stored in an accumulator until a predetermined period of time expires to thereby output it as an AC output via an inverter.

Abstract: A circuit disables an on-board voltage regulator when an upgrade voltage regulator is installed. The system including the voltage regulator disable circuit of the preferred embodiment comprises an on-board voltage regulator circuit, a receptacle, coupled to the on-board voltage regulator circuit, for receiving an upgrade voltage regulator module, and a disable circuit coupled to the on-board voltage regulator circuit and the receptacle, the disable circuit being activated upon insertion of the upgrade voltage regulator module to disable an output of the on-board voltage regulator circuit.

Abstract: A change-over switch performs switching between two different power supplies after connecting both power supplies simultaneously for a given time period. A controller controls the change-over switch to perform the switching operation around a synchronous point of the power supplies. Voltages of the power supplies are monitored to derive a difference voltage therebetween. From the difference voltage, a phase difference between the voltages of the power supplies is monitored. A plurality of low voltage detectors are provided for monitoring the difference voltage. The low voltage detectors are arranged to be operated at voltage values no more than preset values, respectively. The controller outputs a switching command to the change-over switch when time intervals between adjacent operation start time points of the low voltage detectors are all greater than preset values, respectively, and when the low voltage detectors are all operated.

Abstract: In an IC chip having multiple power supply rails, ESD protection circuitry is provided. The ESD protection circuitry protects each power supply rail from an ESD impulse with respect to ground and with respect to the other power supply rails. The ESD protection circuitry is power sequence independent thereby eliminating any restrictions on the sequencing of power as applied to, and removed from, the different power supply rails of the IC chip. A discharge device is controlled by a biasing device such that ESD impulses are passed through the discharge device, but power supply current is not passed therethrough during power sequencing.

Abstract: An energy efficient uninterruptible regulated power supply includes a full wave rectifier that is responsive to AC main power generating an unregulated DC voltage signal, a power factor correcting boost converter coupled to receive and selectively increase the unregulated voltage signal to generate a boosted voltage signal, a battery and a single ended forward converter having a primary winding coupled to receive pulse width modulated energy from the boosted voltage signal and a secondary winding couple bidirectionally to the battery with pulse width modulated control. A first controller pulse width modulates the boosted voltage and battery signals coupled to the primary and secondary windings, respectively, to regulate the output voltage while a second controller operates independently of the first controller pulse width modulate the boost converter to regulate the voltage of a transformer secondary signal that is coupled to the battery.

Abstract: Two power sources are connected to a load by a pair of MOSFET control switches, each connected respectively in series between one of the sources and the load, with their integral diodes forwardly biased between the power source and load. An isolating MOSFET switch is connected in series between the pair of MOSFET control switches and the load with its integral diode back biased between the power sources and the load. Two control lines control the on-off state of all three MOSFET switches so that the isolating MOSFET switch is on when either control switch is on and is off when both control switches are off.

Abstract: A power line conditioner in which a plurality of outlets are mounted on a housing for receiving AC plugs from a plurality of electrical components. The housing is connected to a source of AC power which is distributed to each of the outlets, with the AC power associated with the outlets being processed to improve the performance of the components connected to the outlets. The AC power processing at one or more of the outlets differs from the processing at one or more of the other outlets so that the outlets can accommodate components with different electrical characteristics.

Abstract: A communication cable used to connect a peripheral device to a computer has a first cable, a second cable and a patch unit. The first cable encloses a set of power lines and a set of data lines, and the second cable encloses a set of data lines. The patch unit includes a socket with first and second contacts. In the patch unit, the sets of data lines of the first and second cables are connected. One of the power lines is connected to the first contact, and another of the power lines is connected to the second contact. The first cable connects the patch unit with the peripheral device, and the second cable connects the patch unit with the computer. When power is applied from an external source to the first and second contacts, the power is supplied from the first and second contacts to the peripheral device.

Abstract: In a power supply control system including first through N-th power supply units for generating first through N-th output voltages, the first through the N-th power supply units producing first through N-th failure signals on occurrence of failure in the first through the N-th power supply units, respectively. A sequence control unit carries out a power on sequence which is for sequentially putting the first through the N-th power supply units into an on state in voltage increasing order of the output voltages and carries out a power off sequence which is for sequentially putting the first through the N-th power supply units into an off state in voltage decreasing order of the output voltages.

Abstract: A power supply system for a subsystem in a weapons system, having a filtering arrangement divided into three stages, the first stage providing coarse filtering for the subsystem, a second stage providing filtering for each of a plurality of sub-areas of the subsystem for filtering signals to individual devices within a given subarea.

Abstract: A portable electronic system which has two electrically separate battery banks in a single removable battery pack. A power-management controller switches between the two banks in service--even when neither of the banks is exhausted--to provide optimal active and resting times for the batteries.

Abstract: This invention relates to an improved laser printer power supply that maintains 24-, 12-, and 5 volt DC power to run exhaust fans for a brief period after the power switch is turned off. These fans remove undesirable ozone from the photo-conducting print drum so as to extend the life of the photo-conductor. The circuits utilize a timer circuit and an optically isolated photo-diac to turn a power triac on and off.

Abstract: An electric vehicle control device including a collector for extracting power from an overhead wire and a circuit breaker for breaking the power. The power includes first AC power in AC power source zone and first DC power in DC power source zone. The device also includes a changeover device for changing over the power to apply the first AC power to an AC side or the first DC power to a DC side, a transformer connected to the AC side of the changeover device for transforming the first AC power into second AC power, a first opening/closing device, a power converter for converting the second AC power to second DC power and an inverter for converting the second DC power into third AC power. The third AC power is supplied to drive an electric motor. The device further includes a second opening/closing device, a filter inductor and a filter capacitor connected between positive and negative terminals of the DC input side of the inverter.

Abstract: A dual discharge photovoltaic module responsive to high and low loads. The module includes a first plurality of series connected, high short circuit current cells, and a second plurality of series connected, low short circuit current cells connected in series with the first plurality. A diode is connected in parallel with the second plurality of cells such that current flow through the module when the module is under low load reverse biases the diode so that the module discharges at a low current. When the module is under high load, current flow through the module forward biases the diode and bypasses the second plurality of cells so that the module discharges at a high rate. The module is particularly useful for starting and running an electric motor.

Abstract: A power source device of an expansion unit determines whether an electric device is connected to the expansion unit, and supplies an operating power source voltage CC to the electric device only when the electric device is connected to the expansion unit. Further, the power source device outputs a preset command to the electric device, and supplies a charging power source voltage B-CC to the electric device in accordance with device kind indicating information output from the electric device in response to the preset command. Also, when the power supply device of the expansion unit is in an abnormal state, the power supply device of the expansion unit detects the abnormal state, and outputs the electric device to a state signal representing the abnormal state and execute power source interruption processing of the power source device. In the electric device, power source interruption processing of a power source device of the electric device is performed in response to the state signal.

Abstract: A power supply apparatus for a vehicle includes an alternator for generating an output voltage for charging a first battery and a second battery having a higher voltage than the first battery. The output voltage of the alternator is controlled by a voltage regulator in accordance with the rotational speed of the alternator. When the rotational speed is in a low speed range, the voltage regulator controls the output voltage of the alternator to a first value suitable for charging the first battery. When the rotational speed is in a high speed range, the voltage regulator controls the output voltage of the alternator to a second value higher than the first value and suitable for charging the second battery. The output voltage of the alternator is switched between the first value and the second value at a rotational speed at which the output power of the alternator at the first output voltage equals the output power at the second output voltage.

Abstract: A multibillboard system has a matrix of display monitors for displaying an image on a single screen. Electric energy from a power supply is supplied through a main power supply switch to the display monitors. In response to a power-on remote control signal, the electric energy from the main power supply switch is supplied to the display monitors to energize them successively with respective different time delays. Since the display monitors are energized successively, not simultaneously, any rush current flowing to the multibillboard system is reduced when the multibillboard system is turned on.

Abstract: A scheme for maintaining current balance within a plurality of semiconductor devices, particularly thyristors and gate turn-off thyristors, which plurality is connected between two electrical power sources which devices are configured to be simultaneously conductive to share the current between the two sources, employs the scheme for maintaining the current within the several devices of the plurality equal. The scheme provides for the generation of individual current signals which represent the individual current magnitudes within the several devices. Further generated is an average current signal representing the average current within the plurality. A difference signal is generated with respect to each of the individual current signals which represents the difference between the average and the individual current signal.

Abstract: An Ethernet adapter card for automatically switching a workstation into a network is provided. The adapter card utilizes a current circuit to sense current drawn by an external communications network and a circuit for automatically switching between a card-mounted internal transceiver and the network's external transceiver whenever the external network is coupled to the workstation via an AUI port. The adapter card provides for default selection of the internal transceiver when the external communication network is disconnected from the workstation AUI port.

Abstract: A circuit (10) for transferring power delivered to a load (16) from a primary voltage source (12) to a secondary power source (14) uses three transistors (32, 40, 46) which switch whenever there is a loss of power from the primary source (12). A capacitor (36), interposed between the first transistor (32) and the second transistor (40) attenuates the signal from the first transistor (32) after a predetermined amount of time to switch the second and third transistors (40,46) to isolate the load (16) from the secondary power source (14).

Abstract: An apparatus for controlling a power supply of an electric machine in a vehicle comprises primary and secondary power supplies for supplying an electric power to the electric machine. In an engine-off state the primary power supply is selected as a power supply for the electric machine when an electric power consumption of the electric machine is over a predetermined value, indicating an operating mode, and the secondary power supply is selected when the consumption is below the predetermined value, indicating a waiting mode. Therefore, the absentee receiving of facsimile information, the absentee recording of telephone message, etc. are carried out, even in an ignition-off state. The secondary power supply is used mainly in the case that the electric machine is in waiting mode, so that the complete exhaustion of the secondary battery can be prevented.