Abstract: An aircraft emergency lighting system including: a plurality of units having communication devices arranged to communicate wirelessly with a master controller, wherein each unit is wired to a common power supply for powering the unit in a first mode of operation and has its own back-up battery power supply for powering the unit in a second mode of operation, and wherein the device is provided for off-load testing the back-up battery power supply of each unit and indicating if the unit is operational.

Abstract: A multipurpose radio is disclosed to include a power control unit, which uses a rechargeable battery to provide the necessary working voltage to a LED lamp for illumination, a hand-driven dynamo to generate electricity for recharging the rechargeable battery, a power adapter for charging the rechargeable battery with city power supply, a radio circuit unit for receiving AM and FM radio broadcasting signals, TV audio signals and NOAA signals, and a function mode display unit, which uses a speaker for voice output, a screen for data display, and a selector key for frequency selection.

Abstract: An upgradeable communications patch panel is provided. Embodiments of such a panel include multiple jacks that are configured to receive multiple communications cables and a power interface that is configured to connect to a power device and provide power to a remote communication device via one of the multiple jacks and a corresponding one of the multiple communications cables.

Abstract: The wireless power transmission is a system for providing wireless charging and/or primary power to electronic/electrical devices via microwave energy. The microwave energy is focused onto a device to be charged by a power transmitter having one or more adaptively-phased microwave array emitters. Rectennas within the device to be charged receive and rectify the microwave energy and use it for battery charging and/or for primary power. A communications channel is opened between the wireless power source and the device to be charged. The device to be charged reports to the power source via the channel a received beam signal strength at the rectennas. This information is used by the system to adjust the transmitting phases of the microwave array emitters until a maximum microwave energy is reported by the device to be charged. Backscatter is minimized by physically configuring the microwave array emitters in a substantially non-uniform, non-coplanar manner.

Abstract: An assembly for monitoring an environment includes a RFID tag and at least one sensor assembly. The sensor assembly is configured to sense information regarding the environment around the assembly and convert a sensed event into power to at least partially power operation of the RFID tag.

Abstract: A monitoring system for use in a building, such as a hospital provides an audible and/or visual alarm. The monitoring system includes a control unit, with a plurality of medical condition monitoring units, such as ventilators, connected thereto. A plurality of speakers and/or light sources are connected to the control unit, and are located at various different spaced-apart areas within the building. An abnormal condition, sensed at one of the plurality of medical condition monitoring units, is reported to the control unit, which in turn causes the plurality of speakers and/or light sources to issue an audible/visual alarm. An adaptor can connect a medical condition monitoring unit to the control unit. The adapter may include circuitry to render an alarm output of the medical condition monitoring unit compatible with the control unit, and to suppress an alarm output for a predetermined period of time.

Abstract: A transfer switch configured particularly for use with traffic signal controllers, to enable a traffic signal controller to be powered by a portable electrical generator, when utility line power is unavailable. A housing, configured to be mounted either on the surface of a traffic signal controller cabinet, or recessed into an opening of the cabinet, so as to be flush to the surface thereof, is provided. The housing is configured to be substantially weatherproof without requiring the use of gaskets.

Abstract: A transmit antenna (3) is supplied with energy by a power supply unit (2). An electrical value characteristic for the transmit power is compared to a comparison value and the length of a time interval is measured in which the characteristic value at least reaches or exceeds the comparison value. Depending on the length of this time interval the transmit power is set.

Abstract: A solar panel incorporating a selectively actuable energy availability indicator arrangement. The arrangement includes a visual indicator, such as an LED, and a selectively actuable button. Actuation of the button completes a circuit to read the level of energy available. A resistor in series with the LED as it is connected to the terminals of the solar panel limits the current flow through the LED. A blocking diode connected in series with a charging battery prevents the LED from reading the charge of the battery.

Abstract: An emergency light for providing illumination during emergency conditions with a housing, a light source, and a drive arrangement for driving the light source between retracted and extended positions. Flanges, which can be removable, can project from the housing. Fastening arrangements each comprising a mounting bolt in combination with a locking clip can retain the emergency light in relation to a support surface. A motor in combination with a drive screw threadedly engaged with the light source can form the drive arrangement to produce an axial movement of the light source. A limit switch can sense a position of the light source, and a reflector can guide light from the light source. An emergency condition sensor can trigger an extension and illumination of the light source. A battery can power the light during a power failure. Plural lights and a central control unit can form an emergency lighting arrangement.

Abstract: A system for, and method of, providing device integrated battery backup with power source monitoring and manipulation and a public safety communications infrastructure incorporating the system or the method. In one embodiment, the system includes: (1) a power supply couplable to a primary source of electric power, (2) a network interface, coupled to the power supply and configured to allow the power supply to be remotely controlled and monitored, (3) a rechargeable backup source of electric power coupled to the power supply and (4) a nonrechargeable backup source of electric power coupled to the power supply, the power supply configured to monitor the primary source and the rechargeable backup source and select one of the primary source, the rechargeable backup source and the nonrechargeable backup source based thereon.

Abstract: A wireless communication method and protocol, and wireless devices and systems for stimulation, are provided for communication between a wireless device and a charging device. During active wireless charging, communications (data transmission) from the wireless device to the charging device occurs via pulse loading the receive antenna of the receiving device. Because switching regulation in the receiving device may interfere with the communications, the switching regulation is disabled during a communications window. To further reduce the likelihood of misinterpretation of signals detected in the charging device resulting from the switching regulation or noise, the data bit rate of the pulse loading communications is maintained higher than the switching regulation frequency.

Abstract: Portable and wearable chemical detector devices, such as badges, that are analyte-general, rather than analyte-specific, and which provide an optimal way to notify and protect personnel against known and unknown airborne chemical hazards. The devices are advantageously low-cost, have low-power requirements, may be wearable and are designed to detect and alarm to a general chemical threat. A sensor device includes two or more sensor devices, a processing module coupled to each of the sensor devices and configured to process signals received from each of the two or more sensor devices to determine an environmental state; and a communication module that communicates information about the environmental state to a user.

Abstract: A home automation module having an externally powered communications port. The module includes an automation microprocessor for controlling the module, a communications port for enabling the module to draw power in limited quantities from an external source, a receiver/transmitter section, a power line carrier (PLC) coupler for enabling the transfer of signals between the module and a main while electrically isolating the module from the main, a zero-crossing detector for monitoring the phase of the power on the main while maintaining substantial electrical isolation of the module from the main, and a boost regulator for enabling the module to derive sufficient power from the communications port to drive the PLC coupler during signal transmissions from the module to the main. The detector maintains substantial electrical isolation through an opto-isolator. The boost regulator stores up power over time so that sufficient power will be available when the demand is made.

Abstract: A system master unit is connected to a 24V AC power source. One or more slave units is connected to the master unit by a power/communication line. Bulk capacitance in the master and slave units stores power during a power source positive half cycle. When the source voltage is higher than the bulk capacitance voltages, power is delivered to the loads, during which time communication cannot take place over the power/communication line. During the power source negative half cycle, the power/communication line is disconnected from the AC power source and is then used for communication between the master and slave units. System power is delivered from the energy stored in the bulk capacitance.

Abstract: Described are a system and method of testing connectivity between a main power supply and a standby power supply. The system includes a processor, a main power supply, and a standby power supply. The processor issues a command to the standby power supply to provide dc power to main power supply. The standby power supply switches from providing ac power to providing dc power to the main power supply in response to the command. The main power supply, in response to receiving dc power from the standby power supply, provides a communication that operates to indicate to the processor that the main power supply is receiving dc power from the standby power supply in response to the command.

Abstract: A position display system for displaying a position of a device, the system including a device, a position measuring device that measures a position of the device and a host readout device that is mounted at a first location. The host readout device receives a signal from the position measuring device that is representative of a position of the device, wherein the host readout device includes a display that displays an image representative of the position of the device. A remote readout device that is mounted at a second location, wherein the remote readout device includes a display that displays the image.

Abstract: A backup electrical power unit for an alarm panel. The unit comprises a solar panel array which produces an array output DC voltage and a charging current for a battery through a first circuit at a first voltage level of the battery output voltage. This circuit disconnects the array output from the battery terminal output at a second battery voltage level. The charging current resumes when the battery output voltage is at or below the first voltage level. The backup unit also includes a second circuit interposed electrically, serially with the first circuit to disconnect the array output from the battery terminal output below a disconnect, voltage level. A circuit is provided for connecting the battery to the alarm panel when the primary power to the alarm panel is interrupted. Status indicators are provided.

Abstract: A USB (universal serial bus) controllable power supply and method for supplying power to a circuit board device under test (DUT) via a controllable power supply. The power supply employs a USB interface to communicate with external devices, such as a host computer. In response to power supply control commands from the host computer, the controllable power supply provides various power outputs at various external connectors, including main power, ATX12V power, and peripheral power to be used for peripheral devices corresponding to a DUT test apparatus. The controllable power supply also provides a built-in short circuit check function, and monitors the voltage levels of its power outputs to ensure they are within predefined limits. The power supply also supports emergency shutdown operations, and provides an EOS (emergency overstress) function. In one embodiment, the power supply includes an integrated USB hub.

Abstract: An energy conserving tracking tag for receiving a radio frequency location data signal from a global positioning satellite and for communicating with a tracking system. The tag includes a receiver circuit for receiving the location data signal from the global positioning satellite, a customer ID module for generating a unique tag identification signal, a transponder circuit for receiving command signals from the tracking system, and a power circuit electrically engageable with a battery power supply and an external power source. The tag also includes a programmable microprocessor in electrical communication with the power circuit, receiver circuit, customer ID module, and transponder circuit. The microprocessor is operative to collect the location data signal, the identification signal, and the command signals, and subsequently produce an composite output signal. The transponder is further operative to transmit the composite output signal to the tracking system by radio carrier wave.

Abstract: The present invention a method and apparatus for providing a visual messaging device for use with a high-speed network and an electrical supply system for the visual messaging device. The visual messaging device includes a network interface circuit that receives the message data from a network and arranges it in memory unit in usable form (packets) for use by a processor at the high network speed. The electrical supply system utilized with the visual messaging device comprises, in part, a power source, located in a remote location relative to a low voltage, high current device, which provides for the transmission of electrical power to the low voltage, high current device, such as a visual display unit, via relatively thin wiring or cabling passing through an enclosure, such as a plenum air space, without the need of placing the wiring or cabling in a conduit.

Abstract: The invention involves systems and methods of providing energy to land-based telemetry devices wherein the energy storage and power conditioning system is comprised of an input power supply, an energy storage element, an output supply and a control system. The input power supply provides energy to the output power supply and charges the energy storage element. The energy storage element is comprised of one or more UltraCaps and supplies energy to the output power supply at times of peak need and when the primary energy source to the input power supply is removed. The control system adjusts the voltage supplied to the energy storage element by the input power supply according to changes in the ambient temperature to compensate for changes in the internal equivalent series resistance of the UltraCaps caused by the change in ambient temperature. The output power supply provides energy to the land-based telemetry device.

Abstract: An on-vehicle camera calibration device is provided and a method of calibrating an on-vehicle camera easily is carried out by using a calibration indicator other than a three dimensional one. The calibration indicator makes it possible to set camera parameters to form an image on an arbitrary portion of a screen. The calibration indicator is in the form of a planar calibration indicator TB. A camera picked-up image including the calibration indicator TB is displayed on a screen on which a window is also displayed in superposed fashion. The position of the window is changed in a 2D image coordinate system. The position of the window is adjusted by manipulating an adjust button 7 so that the calibration indicator TB falls within the window. When the calibration indicator TB is placed in the window in coincident fashion, the resultant camera parameters (unknown roll &thgr; r, tilt angle &thgr; t, and pan angle &thgr; p) are set as camera parameters of the camera 17.

Abstract: A rectifier generates a rectified output and a dc power output. The rectifier has an antenna element, a tuning capacitor, a coupling capacitor, first and second rectifying diodes, and a storage capacitor. The antenna element and the tuning capacitor are coupled in parallel and grounded at one terminal. The first rectifying diode is grounded at its anode terminal and the storage capacitor is grounded at one terminal. The coupling capacitor is coupled between the ungrounded terminal of the antenna element and the cathode terminal of the first rectifying diode. The anode terminal of the second rectifying diode is coupled to the cathode terminal of the first rectifying diode. The cathode terminal of the second rectifying diode is coupled to the ungrounded terminal of the storage capacitor. The rectified output is generated between the rectifying diodes. The dc power output is generated between the second rectifying diode and the storage capacitor.

Abstract: A flight information communication system has a plurality of RF direct sequence spread spectrum ground data links that link respective aircraft-resident subsystems, in each of which a copy of its flight performance data is stored, with airport-located subsystems. The airport-located subsystems are coupled by way communication paths, such as land line telephone links, to a remote flight operations control center. At the flight operations control center, flight performance data downlinked from plural aircraft parked at different airports is analyzed. In addition, the flight control center may be employed to direct the uploading of in-flight data files, such as audio, video and navigation files from the airport-located subsystems to the aircraft.

Abstract: A signalling beacon comprised of a lighting indicator which is mounted in a body enabling the stacking thereof. An energy accumulation device, at least one photovoltaic cell and an electronic device of the beacon are in the beacon. The electronic device has a radio frequency receiver circuit to receive radio communication signals which are emitted by an emitter circuit, and a light indicator control circuit. The light indicator control circuit includes a timer, a logic circuit intended to the polarization of the timer and of the light indicator, and a connection device for the switching off of the energy accumulation device when the beacons are piled up. A signalling beacon is obtained with a high autonomy, which is also remotely controllable and it has a high versatility of applications.

Abstract: A rechargeable emergency lamp tube includes a lamp tube holder, the lamp tube holder having a base adapted to obtain AC power supply from an electric socket and a socket adapted to hold a tube for emitting light, a rechargeable battery and a control circuit board mounted inside the lamp tube holder, the control circuit board driving input AC power supply to charge the rechargeable battery and, converting DC battery power supply into AC power supply for the tube upon power failure.

Abstract: Method and apparatus for remotely supplying power to devices to consume less power.

Abstract: A device, system and method for providing power in a secure manner to a network device connected to a network, such as an Ethernet network for example. The device is optionally implemented as an intelligent power supply, which is able to interrogate the network device before power is supplied, in order to determine the electrical capabilities of the device and/or whether the device is authorized to be connected to the network. Such an intelligent power supply preferably communicates with a low power communication device at each network device, which supplies the necessary information upon request.

Abstract: A portable data device (400) having a power controller (430), a clock generator (428) and a digital circuit (432). The power controller (430) has an output signal. The output signal is representative of available power. The clock generator (428) is coupled to the output signal of the power controller (430) for generating a variable clock rate corresponding to the output signal. The digital circuit (432) is coupled to the clock generator (428), and the digital circuit (432) is controlled by the variable clock rate.

Abstract: A cordless power transmission system can transmit and receive power stably without malfunctions. A power transmission terminal transmits default power to an electrical appliance by diffractive electromagnetic waves. The electrical appliance transmits its own unique data and required power intensity data to the power transmission terminal by diffractive electromagnetic waves. A network host assigns an ID to the electrical appliance. Under the control of the network host, the power transmission terminal transmits the assigned ID data and the power with the required intensity to the electrical appliance by rectilinear electromagnetic waves.

Abstract: A portable data device (400) having a power controller (430), a clock generator (428) and a digital circuit (432). The power controller (430) has an output signal. The output signal is representative of available power. The clock generator (428) is coupled to the output signal of the power controller (430) for generating a variable clock rate corresponding to the output signal. The digital [ath0228]circuit (432) is coupled to the clock generator (428), and the digital circuit (432) is controlled by the variable clock rate.

Abstract: Disclosed is a specific location public alert devices that require no specialized installation and may be plugged into any common household electrical outlet which provides power to the device so no switch is required to access power. The device requires no switch for the user to activate the device and its alert which is activated by an incoming transmission from an authorized authority with access to a transmitting source in the specific area of the device(s) such as cell phone towers or transmitting vehicles and activates any number of devices within one home and or all homes simultaneously and the alert may be a tone, light, or voice. The device may be mobile and be able to be removed from the electrical outlet and powered by replaceable or rechargeable batteries at remote locations, cigarette lighter adaptor within a vehicle, or electrical outlet at any location desired.

Abstract: An emergency power station for traffic signal controllers having a general utility power supply, the emergency power station having a small footprint cabinet containing a fuel supply in a lowermost compartment, an engine and an electrical generator in a middle compartment, and a power station controller box in an uppermost compartment, the power station controller box having a power circuit connected to the utility power supply, the electrical power generator and the traffic signal controller, the power circuit including an activatable power switch selectively connecting the utility power supply or the power generator to the traffic signal controller, the power station controller box also including a control circuit with a power line monitor and a programmable timer system for sensing a power loss in the utility power supply, and, after a predetermined delay, activating the engine and switching the switch connecting the traffic signal controller to the power generator.

Abstract: Embodiments of an emergency evacuation system are disclosed which may be installed within the knockouts of a panel of a modular work space system. During normal operation a battery power source within the emergency evacuation system is charged by normal AC power supplied through the modular work space system. In the event of a power outage or fire, the battery power source serves to operate emergency lighting.

Abstract: An interface circuit including an interface controller operated by at least a system power supply or an external power supply. A switch is connected between an interface controller and a system power circuit for conducting system power. The interface controller includes a control signal generating circuit for generating a control signal that closes the switch at a timing that does not affect data transmission performed by the interface circuit in accordance with a trigger signal, which indicates that the system power has gone on. Similarly, the switch is opened at a time when data transmission will not be affected.

Abstract: An emergency power station for traffic signal controllers having a general utility power supply, the emergency power station having a small footprint cabinet containing a fuel supply in a lowermost compartment, an engine and an electrical generator in a middle compartment, and a power station controller box in an uppermost compartment, the power station controller box having a power circuit connected to the utility power supply, the electrical power generator and the traffic signal controller, the power circuit including an activatable power switch selectively connecting the utility power supply or the power generator to the traffic signal controller, the power station controller box also including a control circuit with a power line monitor and a programmable timer system for sensing a power loss in the utility power supply, and, after a predetermined delay, activating the engine and switching the switch connecting the traffic signal controller to the power generator.

Abstract: A backup arrangement for alarm system includes an electronic switch circuit, a DC power source, a build-in electronic Hi-sounder, and a chargeable resistor. The electronic switch circuit, which is a IC control system, has a power input connected to an auxiliary power output of a control panel of a burglary alarm system installed in house or vehicle, and an alarm input connected to an alarm output of the control panel. The electronic switch circuit further includes a normally opened switch and a normally closed switch. The normally closed switch is coupled in series with the alarm output of the control panel and the input of the build-in electronic Hi-sounder. The DC power source has an output connected in series with the normally opened switch and the input of the build-in electronic Hi-sounder. An alert output is connected to a system warning device of the burglary alarm system.

Abstract: A control circuit adapted to be switched to a standby mode during periods without control requirement and to be repeatedly reset during the standby mode of operation for a short wake-up period each to a full mode of operation. The control circuit comprises a standby oscillator that is operative also in the standby mode and that is adjusted during wake-up periods.

Abstract: A system for testing the electrical integrity of an illuminated exit sign alternately powered by a battery, rechargeable from a source of alternating current power. The system includes an alarm for indicating an electrical failure, precluding the illumination of the exit sign. A circuit tests the presence of battery electrical power for illuminating the exit sign. In addition, the circuitry periodically tests for the provision of adequate battery power to achieve the same function. Moreover, the system periodically tests and retests for adequate recharging of the battery during a preselected period of time and includes an alarm for indicating failure of the recharging system.

Abstract: A simplified serial data bus provides interconnection between equipment such as computers, imaging apparatus, and consumer electronic devices. The simplified bus utilizes the cable and connectors of a data bus standard. An apparatus for data communication comprises a connector for receiving a plurality of signal carrying conductors. A control circuit is coupled to the connector for supplying a control signal to one of the plurality of conductors. A detector is coupled to the connector for detecting a voltage source on the one of the plurality of conductors. The control signal is inhibited responsive to detection of the voltage source.

Abstract: A power service unit suited for providing conditioned power to a consuming device at a remote location. The power service unit includes a charger/rectifier, a back-up power supply, together an automated dialer that contacts a central monitor in the event there is a disruption in the operation of the power service unit. The charger/rectifier accepts an external AC power and converts the external AC power to an internal DC power. The internal DC power maintains the back-up power supply in a fully charged state and the converter accepts the internal DC power and converts the internal DC power to an external DC power as required by the consuming device.

Abstract: A smoke detector that comprises three different power sources. First one is the 110/220 volt AC house current, through a step down transformer or that can be hard wired into the home or factory. Second one is a moveable 9 volts rechargeable backup battery. Third one is a solar cell array with a plastic lens that provides up to 9 volts of current through a trickle charger/voltage regulator. The trickle charger also used to recharge the backup battery. With the trickle charger, the solar cell array can cause the smoke detector to alarm with only enough ambient light. The instant invention of the smoke detector unit overcomes the limits of the now market available smoke detectors, by being adjustable, moveable providing more current via the solar cell array to provide a complete recharge to the backup battery. Any voltage lower than 9 volts will lower the charge of the 9 volt rechargeable battery to the current 8 volts to 8 volts and so on up to 9 volts.

Abstract: A measuring unit which is not easily accessible often has a power source which supplies power to the elements for the measuring operation, more particularly, the conversion of an analog measured signal into digital measured data, and for storage thereof, as required. These measured data of a measuring unit are transmitted to a base station without any contact being made the moment this base station is brought into the neighborhood of the measuring unit and transmits a signal. For a minimum load on the power source power from the power source is not supplied to the transmitter for the transmission of measured data from the measuring unit to the base station. Instead, a signal transmitted by the base station provides transmission power. In the measuring unit this signal provides a voltage for feeding the transmitter.

Abstract: This invention provides a new and improved emergency alarm system comprising a central control unit which is directly or indirectly connected to every other component of the emergency alarm system. The central control unit triggers and stops a visual alarm generator and an audio alarm generator, either simultaneously or separately, upon receiving signals from other components of the emergency alarm system. A portable control element and a signal-generating detection means are used for starting and stopping the central control unit, which in turn triggers a power supply means to cause a change, through the visual alarm generator, in color of a visible outdoor board and to commence, through the audio alarm generator, an alarm. A hidden sensing circuit can serve as the signal-generating detection means. The present invention also presents a method of application of said emergency alarm system.

Abstract: A circuit for actuating a door chime has a dc power source in series with a resistor and in shunt with a capacitor. A remote push button transmits a radio signal to the circuit, to connect a solenoid in series with the power source and the resistor and in shunt with the capacitor, which causes a relatively large pulse of current from the instantaneous combination of the power source current and the current from the charge of the capacitor to be applied to the solenoid which is arranged to strike a tone bar. The resistor in series with the capacitor has a time constant that charges the capacitor adequately between cycles of the operation of the push button and the resistance of the resistor limits the current flow from the power source.

Abstract: The present invention provides an auxiliary backup device of burglary alarm system, connected with an alarm output and an auxiliary power output of a burglary control panel and an alarm device, comprises in combination an electrical circuit having a relay means and a DC power source. The relay means comprises a diode connected in parallel with an operating coil which induces a normally opened switch and also a normally closed switch. The two terminals of the diode are connected to the auxiliary power output of the control panel. The normally opened switch is coupled in series with the alarm output of the control panel and the input of the alarm device, such as an audible and visual warning devices. The output of the DC power source is connected in series with the normally closed switch and the input of the alarm device.

Abstract: A smoke detection and alarm system including one or more low cost battery operated smoke alarms fitted with internal non-rechargeable standby batteries, a reactive primary power supply derived from mains supply, and connecting means for connecting the reactive power supply to each of the system's smoke alarms, the system being characterized in that said reactive primary power supply comprises: means for providing a DC supply of slightly higher than the smoke alarm standby battery voltage; and means for detecting the higher than quiescent current supplied by the reactive power supply when any of the smoke alarms connected as part of the system is in alarm or in self-test mode; and means of lowering the DC supply voltage made available to power the system's smoke alarms when a higher than quiescent current is detected; and said smoke alarms comprise: means by which all the current required under quiescent condition, with primary power available, is supplied by the reactive primary power supply; and means by whi

Abstract: A self-diagnostic circuit for an emergency lamphead is disclosed that is effective during standby operation of the lamphead to indicate whether the lamphead is capable of operating in an emergency mode. The self-diagnostic circuit includes a high-impedance circuit path connected in series with the lamphead and including an indicator, such as an LED, which is energized by a battery current passing through the circuit path and lamphead during the standby mode operation. The battery current is insufficient to illuminate the lamphead, but is sufficient to energize the LED whenever proper electrical continuity exists through the lamphead. A second high-impedance circuit path may be connected in parallel with the lamphead, in order to energize a second LED when proper continuity does not through the lamphead.

Abstract: In a building fire alarm system, the light strobes of a network of strobes are synchronized to flash simultaneously. Each strobe has a charging circuit to charge a capacitor which discharges through a flash tube. Once a capacitor is charged, the charging circuit is disabled. A synchronization pulse is applied through common power lines to trigger discharge of each strobe capacitor through the flash tube followed by recharging of the capacitor.