Abstract: A light source driving apparatus includes; a boosting part which boosts an input voltage received from an input part and generates a driving voltage, a boosting transistor which controls an operation of the boosting part, a rectification part connected between the boosting part and an output part and which transmits the driving voltage to the output part, an integrated circuit which generates a gate signal which controls the boosting transistor, and a protection circuit which generates a protection signal which controls a voltage level of the gate signal according to an output current of the boosting transistor.

Abstract: Driving a lighting device by a driving circuit for providing driving power for driving a lighting device, and by a decoupling unit for electrically decoupling the driving circuit from a lighting circuit. The driving power is transferred at least partially from the driving circuit to the lighting circuit, and the lighting device is arranged within the lighting circuit such that its anode is at ground potential of the driving circuit.

Abstract: The present invention relates to a light emitting diode with enhanced luminance and light emitting performance due to increase in efficiency of current diffusion into an ITO layer, and a method of fabricating the light emitting diode. According to the present invention, there is manufactured at least one light emitting cell including an N-type semiconductor layer, an active layer and a P-type semiconductor layer on a substrate. The method of the present invention comprises the steps of (a) forming at least one light emitting cell with an ITO layer formed on a top surface of the P-type semiconductor layer; (b) forming a contact groove for wiring connection in the ITO layer through dry etching; and (c) filling the contact groove with a contact connection portion made of a conductive material for the wiring connection.

Abstract: A dimming circuit for driving a string of LEDs at constant current has a power converter. A control circuit is coupled to the power converter. A plurality of shunt switches is provided. An individual shut switch is coupled to each LED. Each LED can be shunted individually by the individual shunt switch. The control circuit corrects an internal DC state based on a feedback signal VO so that the output current of the power converter remains unchanged when at least one LED is shunted.

Abstract: A light string includes electrical wires to which a number of bulb sockets are connected in series. Each bulb socket defines a receptacle for receiving and retaining a bulb with the bulb in electrical connection with the electrical wires. A shunt member made of alumina is incorporated in the socket. The shunt member is removably disposed in the receptacle of the socket, independent of the bulb, for being electrically connected to the electrical wires in parallel with the bulb whereby when the bulb burns out, the shunt member maintains the current flowing through the wires. The shunt member further includes an insulation sheath surrounding the alumina section.

Abstract: The present invention relates to a surge current limiting circuit of a filament lamp, meant to be connected in series between the filament and a switch that supplies an a.c. voltage, including at least one controllable active element, for limiting the current to a predetermined threshold value.

Abstract: The present invention includes an airfield lighting and control system for energizing at least one airfield control device and containing a ground fault detection system, comprising: (1) at least one airfield control device; (2) an AC electrical circuit conducting an AC signal and connected to said at least one airfield control device; (3) an inductive device, in electrical contact with said AC electrical circuit, which comprises (a) an inductive coil having an input pole and an output pole, and being loaded by a capacitor; (b) a driver winding for the inductive coil, the driver winding adapted to sense AC current flow through the inductor coil; (c) a sampling resistor connected to the driver winding and adapted to detect AC current in the form of a voltage across the sampling resistor; (d) signal processing circuitry comprising: (1) an inverting amplifier adapted to amplify the voltage; and (2) a phase shifter adapted to shift the phase of the voltage; and (e) a power amplifier connected to the signal proces

Abstract: An arc detection and cut-out circuit is connected to an electronic ballast to detect when arcing occurs and to disable the ballast when arcing occurs. The arc detection and cut-out circuit is comprised of a current detector and a shunt circuit. The current detector detects the current in the electronic ballast to determine if arcing has occurred. If detected, the current detector causes a shunt circuit to shunt the power inverter of the ballast shutting it down. The arc detection and cut-out circuit prevents the power inverter from starting up until the power to the ballast is cycled off and back on.

Abstract: An incandescent bulb for use in a submerged swimming pool light fixture is disclosed, which includes a filament, at least one spring-biased filament support, and a grounding device. The filament support includes an exposed current-conducting portion and is moveable in response to the spring bias. The current-conducting portion of the filament support is arranged to allow it to come into electrical contact with the grounding device when the filament support moves in response to the bias of the spring. The filament is disposed to prevent movement of the filament support when the filament is intact and the lamp is in normal operating condition.

Abstract: A circuit that includes a latch and an oscillator is attached to a common lamp control switch to cause the lamp to flash when the switch is manipulated in accordance with a prescribed pattern. The flashing draws attention to the lamp and is used, for example, in an emergency. In a first embodiment, the circuit is placed in parallel with the switch. In a second embodiment, the circuit is placed in series with the switch. In both embodiments, the circuit is small enough to fit within an existing switch box.

Abstract: A series-resonant ballast for powering at least one gas discharge lamp (16) having heatable filaments (12,15) includes: DC voltage input terminals (B+,B-); an oscillating resonant converter (55,26,51,52,53) for producing high frequency voltage for application to the gas discharge lamp; a control circuit (58) able to receive a control signal from the DC input terminals and from the resonant converter and operable to initiate and stop the oscillations; and direct current blocking circuits (57,50) coupled across the filaments (12,15) and operable to stop flow of the control signal from the DC input terminals, thereby the ballast will not oscillate and will not draw any power from the DC input terminals, whenever the gas discharge lamp is: (i) removed from the output terminals, (ii) is defective, or (iv) is inoperative.

Abstract: In a fluorescent lamp ballast, a high-frequency AC voltage is applied directly across a tuned L-C circuit. The fluorescent lamp is connected in parallel with the capacitor of the L-C circuit and a voltage-limiting means prevents the series-resonating L-C circuit from overloading the source of AC voltage during any period when the lamp is not effective in providing circuit loading. When power is initially applied to the L-C circuit, a control means provides a short circuit across the capacitor; and, by way of a first current transformer, the resulting short circuit current is used for pre-heating the fluorescent lamp cathodes. After about 1.5 second, the control means provides for removal of the short circuit for a period of about 25 milli-seconds, thereby permitting the voltage across the capacitor to grow to a magnitude sufficient to ignite and operate the lamp, while at the same time removing the cathode voltage.

Abstract: A starting capacitor disconnect scheme for a fluorescent lamp system in which each starting capacitor shunts one or more series connected fluorescent lamps until all of the fluorescent lamps are ignited. Following ignition of all fluorescent lamps, each starting capacitor is effectively removed from the ballast. Preconditioning of the fluorescent lamp filaments can be limited to the period of time that one or more lamp loads are shunted by the starting capacitor.

Abstract: A flasher bulb and method of making same by mass production techniques are disclosed. The flasher bulb has first and second nickel wires connected by a tungsten wire to form a loop and a bimetallic strip one end of which is connected to one of the nickel wires, the strip being bent towards the other nickel wire. When the strip is heated by passage of current through the tungsten wire, it makes contact with the other nickel wire to take the tungsten wire out of circuit but retain current flow through the nickel wires. Accordingly in a string of flasher bulbs, extinction of one bulb will not necessary cut off current to the others. The conductive wires and bimetallic strip are assembled in position in a mold and held in place by an insulating disk.

Abstract: A protection system for protecting the secondary windings of current transformers against overvoltages. The protection system consists of a device shunting the secondary winding and having a triggering device operative when the winding is subjected to a voltage higher than the voltage appearing across the terminals of the secondary winding, under normal operating conditions and during a fault on the HV power network. The shunting device comprises a latching relay incorporating a coil which is energized by the triggering device to short-circuit the current secondary transformer through the relay contact, and, also, a voltage regulator connected in parallel with the relay coil. This protection system is simple, compact, lightweight and consumes no energy when the current transformer operates under normal conditions.

Abstract: A glow bottle starter having three lead-in wires and containing two bimetals connected together at one end and a rigid tungsten rod. The bimetals make normally closed contact with the tungsten rod in the quiescent state of the starter, and upon electrical current flow through one or both of the bimetals to cause elevation to a predetermined temperature, the bimetals are operative to separate from the tungsten rod. In a circuit including the glow-bottle starter for starting a discharge lamp, one of the bimetals and the rigid tungsten rod are connected across the output of a ballast circuit, and the tungsten rod and other bimetal are connected across the lamp.

Abstract: A high pressure sodium lamp, which includes a discharge tube enclosing xenon at pressures in excess of 300 torr, is reliably started by the combination of an igniter, a conductor wrapped around the discharge tube, and a switching circuit. The igniter provides periodic pulses of 2500 to 4000 volts with a duration of at least one microsecond. The switching circuit provides a high voltage pulse having an amplitude about equal to the amplitude of the periodic pulses and a duration much greater than the duration of the periodic pulses. The conductor intensifies the electric field within the discharge tube. A conventional lamp ballast provides ac power during starting and normal operation.

Abstract: A plurality of photodetectors in a single line exposed to a field of view transversely across the complete region of a glow discharge volume. The detectors are connected in an electronic circuit to trigger a crowbar device across the power supply circuit providing the voltage producing the discharge when any one detector receives an optical input substantially greater than normal, thereby preventing damage to the discharge electrodes due to arcing across the glow discharge.

Abstract: Circuitry directed to the rapid de-ionization of ultraviolet detectors by increasing the mobility of the ionized gases within the tubes which will enable the tubes to more effectively operate at low temperatures. The circuitry includes connecting circuitry for shorting the elements of the tube such that they will be at the same potential immediately after firing and also includes circuitry for the shunting of the tube immediately after firing to limit the number of ions generated in the discharge process. The shorting of the elements increases the surface area of negative electrodes for the recapture of the ions and the distance through which the ions must travel is reduced by a factor of one-half.

Abstract: Protection apparatus responsive to a fault condition in a high voltage, high current device to be protected; includes an ignitron and a hydrogen thyratron, connected in parallel across the device under protection, such that in event of a fault in the protected device, current is tandemly shunted away from the faulting device. Both the hydrogen thyratron and the ignitron receive simultaneous triggering signals from a fault-detection circuit upon the occurrence of a fault in the device under protection. Since the hydrogen thyratron responds to the fault-trigger signal more rapidly than the ignitron, it establishes a current-shunting path in the first fraction of a microsecond until such time as the slower-responding ignitron can become conductive and carry the brunt of the current to be shunted away from the faulting protected device.

Abstract: A low-pressure sodium vapor discharge lamp and a current stabilizing ballast element are connected in series to an energy source so that the lamp is operated by means of a non-sinusoidal current. The temperature of the wall of the discharge tube is maintained in an accurately defined interval and the instantaneous current density in the tube is kept below a first given value and the effective current density is kept above a second given value. This results in a relatively high luminous efficacy.

Abstract: A flashtube has an hermetically sealed glass envelope containing an inert gas and a pair of electrodes between which an arc discharge path is defined during lamp operation, and an insulated external trigger wire at the outer surface of the envelope. The trigger circuit includes a safety feature in the form of a sealed spaced gap to prevent an arc from occurring in the flashtube in the event that the flashtube envelope is cracked or broken.

Abstract: A filament coil is connected in series with an arc tube to form a self ballasted lamp. An internal starting coil is connected across the arc tube through a bimetal switch, which is normally closed, for energizing the starting coil. When an arc is struck and the tube temperature rises, the bimetal switch opens to cut out the starting coil. A fuse wire is connected across the bimetal switch to facilitate flashing of the filament coil by application of less than rated voltage during evacuation of the lamp envelope when the bimetal switch is normally open because of the elevated temperatures required for glass working and sealing. Upon subsequent application of rated voltage, the fuse wire melts and the lamp operates in its normal manner.