Abstract: A frequency stabilized automatic gain controlled ballast system (10) which is coupled to a power source (12) in order to operate at least one of a pair of gas discharge tubes (40 and 40'). Each of the gas discharge tubes (40, 40') include respective filaments (42, 44 and 42', 44'). A frequency control circuit (11) is coupled to the power source (12) and includes a frequency control transformer (43) and a frequency control capacitor (50) for establishing a constant oscillation signal at a predetermined frequency. A switching network (13) is connected to the frequency control circuit (11) for establishing a pulsating current responsive to the constant oscillation signal of predetermined frequency. Induction circuitry (15) is coupled to the switching network (13) and the frequency control circuit (11) and includes an inverter transformer (78) as well as coupling capacitors (86 and 88) for generating a voltage across the gas discharge tubes (40 and 40').

Abstract: A system operating in combination with a gas discharge lamp, such as a fluorescent lamp having electrodes therein, to effect ignition in a cold state without an ignition delay. Applied across the electrodes through a current-limiting coil is a voltage derived from a standard alternating-current supply. The supply voltage is also applied through an ignition switch to a starter coil inductively coupled to the current limiting coil to define therewith a step-up transformer, such that when this switch is closed, a high ignition voltage is imposed on the electrodes to produce an arc-discharge which heats up the electrodes. The resultant electron emission from the electrodes makes it possible to re-open the ignition switch after a brief interval, the lamp thereafter continuing to operate on the relatively low supply voltage.

Abstract: A starting circuit which is connected in parallel with the lamp. No ballast is required for the starting circuit. The starting circuit uses a pulse transformer, the primary of which is connected into an RC network, the secondary of which is connected in series with a capacitor which prevents current flow at the low frequency open circuit voltage. The circuit being in parallel with the lamp enables the use of low power components such as the pulse transformer, since the lamp operating current does not traverse the circuit as would be the case with a series starting circuit or ballast transformer.

Abstract: A discharge lamp circuit in which the lamp is substantially instantaneously started and in which the power consumption of the lamp after starting is reduced with substantially no vibration due to piezoelectric effects and caused by currents flowing through a nonlinear dielectric element. An inductive stabilizer is connected in series with one of the filaments of the discharge lamp and a nonlinear circuit is connected in parallel with the filaments of the discharge lamp. The nonlinear circuit is composed of a nonlinear dielectric element and a bidirectional switching means connected in parallel with the nonlinear dielectric element. A reverse-conductive circuit is connected in series with the nonlinear circuit and in parallel with the filaments of the discharge lamp, the reverse-conductive circuit including a reverse-conductive semiconductor switch mean which is conduction-controlled in the forward direction but which is always conductive in the reverse direction.

Abstract: In a circuit for the operating of gas discharge lamps in which a starting circuit (2, 17) having a starter transformer (17) and a source of auxiliary voltage which can be disconnected after starting has been effected are provided for the starting of the lamp, there is provided a full-wave rectifier (6) with which a charging capacitor (10) and a voltage-dependent electronic switch element (8) are connected in parallel. A switch contact (9) which is in series with the charging capacitor (10) can be actuated by the switch element (8). The charging capacitor (10) which supplies the operating voltage for the gas discharge lamp (3) can be charged to a voltage which can be selected by means of the switch element (8). The full-wave rectifier (6) which serves a source of auxiliary voltage can be disconnected by means of a control element (4) from the gas discharge lamp (3) after the latter has been started.

Abstract: To insure reliable starting, a superposition igniter circuit utilizes an iliary capacitor (10) which has a resistor (6) connected in parallel thereto. This parallel arrangement is serially connected with a pulse capacitor (7) and a choke (2) to form therewith a series oscillatory circuit which is connected directly with the primary winding (8, 13) of the pulse transformer (4, 11) in order to raise the lamp voltage during ignition. The parallel connection of the auxiliary capacitor (10) and the resistor (6) forms a load impedance for the pulse capacitor (7); the series circuit of the auxiliary capacitor (10) and the pulse capacitor (7) form a high-frequency short-circuit capacitor system. A voltage-sensitive semiconductor switch (9), such as a four-layer diode or a triac, disconnects the auxiliary capacitor (10) after lamp ignition, thus interrupting the series auxiliary circuit, permitting only normal supply voltage to be applied to the lamp (1).

Abstract: A discharge lamp starting device employing a thermal switch which comprises main and auxiliary bimetal electrodes respectively thermally bendable in the same direction, and an auxiliary heater for heating the auxiliary bimetal electrode in addition to a main heater for the main bimetal electrode. The auxiliary heater is energized to heat the auxiliary electrode upon a starting failure specifically when the discharge lamp is to be lighted again immediately after its extinguishment, whereby the auxiliary electrode is forced to bend toward the main electrode and a re-closing of the thermal switch and eventual lamp starting can be accelerated.

Abstract: The invention relates to starting and supplying a low-pressure discharge lamp which comprises two electrodes between which a main discharge path is formed, a shunt path being electrically in parallel with at least a portion of said main discharge path.In accordance with the invention the lamp is started by means of a glow-discharge starter which is shunted by a VDR the threshold voltage of which is lower than a value determined by the geometry of the shunt path, and is higher than the minimum voltage for starting a discharge in the main discharge path. The discharge then only starts in the main discharge path.

Abstract: An electroluminescent lamp driver circuit is disclosed, which includes a timer circuit acting as a retriggerable astable multivibrator interfacing with transistor-transistor logic (TTL) circuitry. The timer circuit sets the operating frequency of the entire lamp driver circuit while the TTL circuitry includes a transistor for controlling the operating voltage of the TTL circuit and two additional transistors for providing the switching for periodically exciting the phosphor in the lamp to luminesce.

Abstract: A discharge lamp lighting device comprises a serial connection of an inductive ballast and a discharge lamp connected across an A.C. power source, and a switching circuit connected substantially in parallel to the discharge lamp and operable to carry out two consecutive ON/OFF operations in the beginning of each half cycle of the A.C. power source while the discharge lamp is in its lit condition. The switching circuit preferably comprises a full-wave rectifier connected substantially in parallel to the discharge lamp, a switching element connected between the output terminals of the rectifier, and a control circuit for controlling the ON/OFF operation of the switching element.

Abstract: The disclosed firing device comprises a fluorescent lamp serially connected to an inductive stabilizer, a first semiconductor switch including an SCR connected across the fluorescent lamp, and a nonlinear dielectric element serially connected to a parallel combination of a PNPN switch as a second semiconductor switch and a discharging circuit across the fluorescent lamp. The discharging circuit may comprise a resistor alone. The first semiconductor switch may include a semiconductor diode and a PNPN switch and the discharging circuit may include a resistor connected across series combination of a semiconductor diode. Alternatively, the discharging circuit may include a Zener diode and a resistor serially interconnected.

Abstract: A ballast circuit for limiting the kilovolt-ampere rating of a ballast required to operate a high pressure sodium lamp during starting, hot restart and lamp out conditions. The ballast circuit includes a voltage limiting or clamping circuit across the secondary of a ballast transformer which responds to the voltage level and the rate of change of voltage across the secondary to activate a switch during each half cycle that the lamp is not conducting current.

Abstract: To operate at least one, and preferably a plurality of fluorescent lamps, a elf-oscillating transistor push-pull switching oscillator, using two similar transistors (T1, T2), is connected to respective lamps (3, 3', 3"), with an oscillatory circuit (4, 4', 4") to operate at audio, supersonic or low high frequency, for example in the 20 kHz range. Each lamp operating circuit has an individual series resonance circuit (4, 4', 4") which includes a ballast inductance (L1, L1', L1") and a capacitor (C1, C1', C1"). For multiple operation, the respective lamp operating circuits are connected in parallel. A special starting circuit (10) and a control circuit (9a, 9b; L2, L2', L2"; L3, L3', L3") for the switching transistors insures low-loss operation.

Abstract: A high-pressure discharge lamp has a starting circuit consisting of a bimetallic switch and a resistor, which is connected in parallel with the arc tube, and is turned on via a mercury lamp ballast. The current which flows into the starting circuit is limited by the current that flows into the arc tube and by the output of the ballast. Therefore, the extinguishing voltage phenomenon that hitherto had developed immediately after the lamp was turned on no longer takes place.

Abstract: An HPS starting aid for providing pulses to an HPS lamp via a ballast tap connection, the aid employing a capacitive voltage divider connected to the power distribution line for charging purposes. There is no power resistor so that the pulse width and amplitude is not dependent on voltage amplitude fluctuations of the line voltage. A voltage breakdown device and a timing RC network determine the pulse positioning of the starting pulse. The size of the capacitors in the capacitive voltage divider and the number of turns on the ballast tap winding determine the pulse width and amplitude.

Abstract: Apparatus for starting and operating a discharge lamp includes a starter device having a normally-closed (N/C) switch including a pair of contacts each connected to a bimetal with the bimetals having opposite flexure deviations. Circuitry is provided for coupling one bimetal to a ballast and also to a discharge lamp whereby short-circuit current flows through both bimetals to open the switch and initiate conductivity of a discharge lamp and through one bimetal to maintain the switch operational and continue lamp conductivity.

Abstract: An electronic ballast system includes a first capacitor (C.sub.2) electrically coupled to the first filament (30) of a gas discharge tube (12) and becomes the power supply of the gas discharge tube (12) subsequent to both its charging and discharging operations. The collector (38) of a transistor (Tr) is connected to the first capacitor (C.sub.2). The primary winding (22) is connected to the first capacitor (C.sub.2) and the collector (38) of the transistor (Tr) in parallel relation. The transformer (t) includes a secondry winding (24) which is connected on opposing ends thereof in feedback relation to the base (44) and emitter (42) of the transistor (Tr). Pulses of opposing current polarity (122 and 124) generated through the secondary winding (24) alternately provide conducting and non-conducting states for transistor (Tr) to discharge and charge the first capacitor (C.sub.2) through gas discharge tube (12) to provide a power source for operation of gas discharge tube (12).

Abstract: A high intensity discharge lamp having a hermetically sealed envelope with support wires therethrough has an arc tube therein with support wires whereby a starter device having first and second contacts of a normally-closed switch has a first bimetal coupling the first contact to one support wire and a second bimetal coupling a second contact to another support wire with the bimetals positioned to flex in opposite directions and enhance the operation of the contacts and of the high intensity discharge lamp.

Abstract: A discharge lamp ballast circuit comprises at least one discharge lamp connected in series circuit with a ballast capacitor and inductor across a pair of input terminals for a source of A.C. supply voltage. A controlled semiconductor switching element is coupled across the lamp electrodes and a control circuit for the switching element is coupled to the input terminals and to a control electrode of the switching element. A voltage dependent non-linear impedance device is connected in shunt with the capacitor so as to limit the capacitor voltage to a predetermined value. The voltage dependent impedance device prevents the occurrence of hazardous voltage levels in the circuit and improves the stability during the warm up phase.

Abstract: A fluorescent lamp starting device in which an electronic starter is provided in the form of a hybrid integrated circuit which is mounted in a standard glow starter case and which can be utilized in a standard glow starter socket of a fluorescent lamp fixture. A nonlinear capacitor and semiconductor switch are coupled in parallel with another and across the external terminals of the starter. The nonlinear capacitor is provided in the form of a thin plate while the semiconductor switch is provided on an IC substrate substantially equal in size to the nonlinear capacitor.

Abstract: An electronic device (20-61) for the starting and a.c. operation of a capacitively stabilized discharge lamp (7) includes a controlled semiconductor switching element (22) which, in the operating condition of the lamp, is briefly conductive in each half cycle of the AC supply. The control circuit of the semiconductor switching element (22) includes a second switching element (25) which, during the starting procedure of the lamp, ensures that the semiconductor switching element (22) is made conductive only every alternate half cycle thereby to improve the ignition of the lamp.

Abstract: Starting and operating circuit for gaseous discharge lamps has device for quickly re-starting extinguished lamps while still hot. Circuit comprises a source of alternating current, an inductive regulator ballast having its input connected to the alternating current source, and a gaseous discharge lamp connected to the output of the ballast, a sine wave oscillator circuit having its input connected to the current supply and having its output connected to a transformer connected in series between the ballast and the lamp for stepping up and applying voltage to a lamp, and a positive temperature coefficient resistor (PTCR) connected between the alternating current source and the oscillator circuit for reducing power to the oscillator circuit when the lamp is inoperative or absent.

Abstract: This discharge lamp lighting device for copying machines is used, for example, for lighting a discharge lamp for electrostatic copying machines of a type in which is reflected light from objects to be copied as irradiated sequentially with a moving light source is recorded on a rotary electrostatic drum. In this lighting device, the lamp current flowed to the discharge lamp is made substantially to be of a rectangular wave form and the substantial non-light emitting section is removed or reduced in the light output wave form of the discharge lamp, whereby an excellent copying result is made to be obtained particularly in such copying machine in which the light irradiation is momentary as referred to in the above.

Abstract: A low wattage high intensity discharge lamp having a quartz arc tube and a glow starter disposed within a bulbous glass envelope containing an inert gas, such as argon, at subatmospheric pressure. The starter within the envelope comprises a first bimetal connected to one of the arc tube lead-in wires, a second bimetal connected to one end of a conductive support wire sealed through the bulbous envelope, and a fixed first contact attached to another conductive support wire sealed through the bulbous envelope and also connected to the other lead-in wire of the arc tube. The bimetals are electrically connected together at one end which makes a normally closed contact with the fixed contact in the quiescent state of the starter.

Abstract: A circuit for starting and operating a low wattage high intensity discharge lamp from a source of AC line voltage. The circuit includes a glow starter device having a first terminal connected to a first bimetal, a second terminal connected to a second bimetal, and third terminal connected to a rigid conductive member, the bimetals being electrically connected together at one end which makes a normally closed contact with the rigid member in the quiescent state of the device. A choke coil and a capacitor are series connected in that order between one of the AC input terminals and the second terminal of the starter device, and a second AC input terminal is connected to the third terminal of the starter. The first and third terminals of the starter device are connected across the discharge lamp terminals.

Abstract: A parallel circuit of a capacitor and a switching element is connected to a hot cathode discharge lamp lighting device using a high frequency and high voltage generating means for permitting the flow of current into the filaments of the hot cathode type discharge lamp only at the lamp starting time. The switching element of the parallel circuit is a current controlled resistance element, such as a switching semiconductor, having a break-over voltage V.sub.BO lower than the capacitor terminal voltage during the initial ignition period and higher than the capacitor terminal voltage during the reignition or operation period, whereby the filament current to the discharge lamp may be used for preheating of the filament in the initial ignition period. The filament current may be stopped or reduced by turning off of the switching element by raising the terminal voltage of the capacitor in the reignition period during normal operation.

Abstract: A fluorescent lighting device which includes a preheating type fluorescent discharge tube and as the ballast thereof an incandescent bulb. The fluorescent lighting device is ignited by the use of a pulse transformer and a neon tube. A semiconductor element may be used in place of the neon tube.

Abstract: A discharge lamp starting device such as for a fluorescent lamp in which a nonlinear capacitor is connected in parallel with a discharge lamp with a Zener diode connected in series with the nonlinear capacitor. A semiconductor switching device, such as a diode thyristor, is connected in parallel with the discharge lamp. Due to the presence of the Zener diode, the semiconductor switching device can have a wide range of threshold voltage so that the cost of the device is low.

Abstract: A converter circuit for addition to the existing lamp operating circuitry of a high pressure mercury lamp consisting of an existing series ballast inductor and a power factor connecting capacitor connected across the input terminals of the existing lamp operating circuit includes inductance arranged to be connected to the ballast inductor so as to adjust the resultant series inductance to a value suitable for a sodium lamp, and an igniter portion coupled to the converter inductance. The igniter portion operates to apply ignition voltage to the sodium lamp during at least part of the time that the converter circuit is supplied with power. Protective circuitry is coupled to the converter inductance to block or limit high frequency voltage pulses which could otherwise reach the ballast inductor.

Abstract: A lighting apparatus which provides for high-voltage pulses for starting a high-pressure sodium discharge lamp and thereafter provides operating ballasting. The apparatus uses two capacitors and associated blocking diodes and a charging resistor. One of the capacitors charges toward the peak of the line voltage in the negative half cycle, and thereafter, when the line voltage goes positive, the voltage on the one capacitor is added to the line voltage for charging the other capacitor. When the voltage on the other capacitor reaches a predetermined voltage exceeding the Zener voltage of a paralleling Zener diode which Zener voltage may be about twice the peak voltage of the line, the other capacitor discharges through a ballast inductor which is connected in autotransformer relationship therewith to provide a high voltage pulse of sufficient magnitude to start the lamp.

Abstract: A visual monitor including a single light indicator for HID lamps (not needing a starter) and a visual monitor including two light indicators for an HID lamp, such as a high pressure sodium lamp, operating in conjunction with the starter. When the lamp is out, the presence or non-presence of an ignited first light indicator indicates lamp failure or ballast failure, respectively. The blinking or nonblinking of the second light indicator indicates whether or not the starter is producing satisfactory starting pulses.

Abstract: Ballasting for a fluorescent lamp is provided by one or more incandescent lamps connected in series between the line voltage source and the fluorescent lamp. Lamp operation is initiated by a triggering pulse applied to a conductive member placed adjacent the fluorescent lamp. In one embodiment, a plurality of incandescent lamps are connected in parallel and are selectively gated into the circuit depending upon exposure requirements for the lamp.

Abstract: A portable fluorescent tube assembly is disclosed having a relatively low voltage electric convenience outlet associated with the assembly. Although higher than normally supplied voltages are needed to initiate the lighting of a fluorescent tube, these voltages are unsuited for energizing still other electrical apparatus which is designed for normally supplied voltages. The circuitry of the present fluorescent tube assembly supplies both relatively high and low voltages at the portable unit itself, so that the tube can be fired to initiate lighting at the relatively high voltage, and yet other electrical apparatus can be energized directly from the portable assembly at a relatively low voltage.

Abstract: A battery-powered electronic strobe flash apparatus has a flashtube, which produces radiation in proportion to the energy delivered to it. A transformer has a primary winding, connectable to the battery, for storing energy in the transformer and a secondary winding, connected to the flashtube, for delivering the stored energy to the flashtube when the primary winding is disconnected from the battery. An actuatable switch has a first condition for connecting the battery to the primary winding to saturate the transformer, and a second condition for disconnecting the battery from the primary winding, thereby causing a substantially constant amount of energy to be delivered to the flashtube, whereby a substantially constant amount of flashtube radiation is produced each time the switch is actuated.

Abstract: A gas discharge lamp is connected across an inductor and in series with a solid state switching device and a resistor, and this combination is connected across a voltage source. This switching device is controlled by a monostable multivibrator, the input of which is connected to the output of a comparator amplifier sensing the difference between the voltage drop across the above-mentioned resistor and a reference voltage which may be changed to vary light intensity. A supply voltage feedback control loop uses a power oscillator to maintain the voltage supplied to the inductor and the lamp at a level corresponding to a symmetrical voltage wave form in the lamp in order to maximize lamp efficiency. A reference voltage feedback control loop controls the reference voltage supplied to the comparator amplifier in order to minimize the effect of power line variations on lamp intensity while allowing controlled variations in intensity by the user.

Abstract: A gas discharge lamp is connected in parallel with an inductor and in series with a solid state switching device and a resistor, and this combination is connected across a rectified AC voltage source. This switching device is controlled by a monostable multivibrator, the input of which is connected to the output of a comparator amplifier sensing the difference between the voltage drop across the above-mentioned resistor and a voltage which bears a predetermined relationship to the rectified AC signal of said source. This results in a high frequency operation of the lamp wherein the lamp current level is controlled or modulated in accordance with the rectified AC supply voltage, providing a high power factor lamp circuit without the normal heavy lamp ballast. In addition, a circuit is disclosed which prohibits the lamp from exhibiting a high resistance when the AC voltage is at a zero crossing point, protecting the solid state switching device and stabilizing the high frequency.

Abstract: A circuit for operating an electric discharge lamp from an a.c. supply wherein a burst of high voltage pulses for starting the lamp is generated during each cycle or half cycle of the supply by rapidly turning on and off an electronic switch, e.g. a triac, connected between a tapping point on a ballast inductance and an input terminal of the circuit.

Abstract: A starting circuit suitable for sodium vapor street lamps is disclosed. The circuit includes a voltage doubler which periodically fires pulses through the lamp ballast. The pulsing is controlled by a neon lamp connected to a gate anode of a triac. When the triac fires the capacitors which form the voltage doubler are shorted across to produce the starting pulse.

Abstract: An electrical circuit for operating an electrical discharge lamp has a pair of terminals for connection to a supply of voltage of substantially sinusoidal waveform, a second pair of terminals for connection with a discharge lamp, a ballast impedance connected between one of the first pair of terminals and one of the second pair of terminals, a starting device for aiding initiation of discharge in the lamp and means for disabling the starting device when a discharge has been initiated in the lamp. The means for disabling the starting device operates in response to a change in the voltage waveform across the second pair of terminals from substantially sinusoidal to substantially square.

Abstract: Direct current ballasting and starting circuitry for efficiently operating a gaseous discharge lamp on direct current. A series-pass switching transistor in one of a pair of input lines alternately switches between on and off states to periodically supply pulses of energy from a source of direct current voltage. During steady-state operation, current sensing circuitry limits the maximum current conductable by the transistor such that the output of the circuitry is current regulated. A filter, in series with the transistor, smoothes the pulses of energy delivered by the transistor into direct current with a comparatively small alternating current component. Starting circuitry in series connection between the filter and an output terminal, senses the nonionized state of the lamp and provides a voltage pulse of sufficient magnitude and duration to initiate ionization in the lamp, but permits uninterfered passage of current through the filter to the output.

Abstract: Circuit operating from a direct current source applies DC pulses to a high pressure sodium vapor lamp to improve the color properties of the lamp. In one embodiment, the circuit includes a charging circuit comprising a first inductor, a diode and a capacitor connected across the DC source, and a discharging circuit comprising a second inductor of lower inductance than the first inductor, a controlled thyristor switch and sodium vapor lamp connected across the capacitor, and a timing circuit for periodically turning on the switch at predetermined intervals. A third inductor and a serially connected diode are connected across the discharging circuit to prevent excessive voltage across the controlled switch and to provide for control of lamp wattage with respect to changes in lamp voltage.

Abstract: Circuit operating from a direct current source applies DC pulses to a high pressure sodium vapor lamp to improve the color rendition of the lamp. The circuit includes a first inductor, a diode and a capacitor connected across a DC source, and a second inductor, controlled thyristor switch and sodium vapor lamp connected in series across the capacitor, and a timing circuit for periodically turning on the switch at predetermined intervals. The circuit provides for charging the capacitor, commutating the controlled switch, and discharge of the capacitor to enable subsequent re-charging thereof, so as to povide the desired pulsed operation of the lamp. This mode of operating also provides for application of voltage to the lamp which is substantially higher than the supply voltage.

Abstract: Circuit operating from a direct current source applies DC pulses to a high pressure sodium vapor lamp to improve the color rendition of the lamp. The circuit includes a thyristor switch in series with the lamp, an RC timing circuit for periodically turning on the switch at predetermined intervals, and an LC circuit for turning the switch off. An inductor in series with a diode across the capacitor of the LC circuit provides for discharge of the capacitor to enable subsequent re-charging thereof, so as to provide the desired pulsed operation of the circuit. This mode of operation also provides for application of voltage to the lamp which is substantially higher than the supply voltage.

Abstract: Color properties of high pressure sodium vapor discharge lamps are improved by disclosed operating circuit for applying pulsed direct current to the lamp. The circuit comprises a direct current supply circuit, a transistor switch in series with a ballast inductor and a lamp across the supply circuit, an SCR switch connected across the inductor, a coasting diode across the inductor and lamp, and a control circuit connected to the switches for applying DC pulses to the lamp at a predetermined repetition rate and duty cycle. The circuit produces pulse waveforms which provide optimum color improvement in the lamp and makes efficient use of the energy supplied from the power source.

Abstract: Color properties of high pressure sodium vapor discharge lamps are improved by disclosed operating circuit for applying pulsed direct current to the lamp. The circuit comprises a direct current supply circuit, a transistor switch in series with the lamp and the primary of a transformer connected across the supply circuit, a diode in series with the secondary of the transformer connected across the supply circuit, and a control circuit connected to the transistor switch for applying DC pulses to the lamp at a predetermined repetition rate and duty cycle. The circuit produces pulse waveforms which provide substantial color improvement in the lamp and makes efficient use of the energy supplied from the power source.

Abstract: Circuit operating from a direct current source applies DC pulses to a high pressure sodium vapor lamp to improve the color properties of the lamp. The circuit includes a controlled thyristor switch in series with the lamp, an RC timing circuit for periodically turning on the switch at predetermined intervals, and an LC circuit for turning the switch off. An inductor comprising the primary winding of a transformer in series with a diode across the capacitor of the LC circuit provides for discharge of the capacitor to enable subsequent re-charging thereof, so as to produce the desired pulsed operation of the circuit, and the transformer secondary winding in series with a diode clamps the voltage of the primary winding. The disclosed arrangement prevents excessive voltage across the controlled switch and provides for the control of lamp wattage with respect to changes in lamp voltage.

Abstract: Increased color temperature of high pressure sodium vapor discharge lamps is provided by improved operating circuit for applying pulsed direct current to the lamp. The circuit includes a direct current ballast circuit having low ripple factor and a pulsing circuit comprising a controlled thyristor switch which operates to apply DC pulses to the lamp at a predetermined repetition rate and duty cycle. The described circuit provides for gradual increase in power applied to the discharge lamp during the starting interval and thereby avoids instability of lamp operation during that stage.

Abstract: Starting and operating ballast circuit for gaseous discharge lamp. Ballast winding comprises a pair of series connected coils each having a portion with a selected number of turns thereof connected in a high voltage starting circuit including a discharge capacitor and a voltage sensitive switch and forming a series discharge loop with the coil portions to provide high voltage, high frequency starting pulses on the lamp.

Abstract: An electronic circuit for starting and operating gaseous discharge lamps. A DC input is connected to a time-ratio control (TRC) circuit which includes a regulating transistor, a sensing resistor and a coasting inductor connected in series. A flyback diode is connected to the inductor for providing a discharge path for the inductor. The TRC circuit serves to ballast the gaseous discharge lamp. An inverter is connected to the TRC circuit for driving the lamp with square waves. A starting circuit is provided and is connected to one of the lamp electrodes for starting the lamp. A transient protection circuit is provided for the inverter to shunt transients back to the input. A TRC drive and control circuit is connected to the TRC regulating transistor and sensing resistor for controlling the regulating transistor.