Abstract: The AC power line to a street luminaire carries a 200 KHz carrier signal for operating a switching relay that connects a dimming reactor in series with the discharge lamp. A pick-off transformer has a primary winding connected in series with the ballasting means for the lamp, and a secondary winding connected to a carrier signal detector operating the switching relay. A capacitor connected across the primary has a value resonating the primary magnetizing reactance of the transformer at the carrier frequency. A resistor substantially higher in value than the characteristic impedance of the line but not several orders of magnitude higher, is preferably connected across the primary winding to serve as a terminating impedance.

Abstract: A discharge lamp ballast for stabilizing wattage input into a discharge lamp at different levels in two or more ranges comprises a magnetic core forming a closed magnetic circuit. A main winding on the core may be used alone or with an extended winding switched in series, and be connected in series with the lamp across an alternating current source in a lamp operating circuit. A control winding on the core has a triac connected across it to vary the current and thereby the wattage supplied to the lamp in the operating circuit. A pair of gapped shunts, one located between the control winding and the extended winding, and the other between the extended winding and the main winding, assure a proportionally greater control effect on the series reactance in the lamp operating circuit when the extended winding is switched in than when it is not.

Abstract: A discrete type starter for HID lamps uses a ferrite core pulse transformer whose secondary is connected in series with the lamp across a ballast output winding. The primary is formed by mounting one or more sidacs and a resistor astride the core loop and interconnecting them by cladding on the board to make two or three turns around the core. The primary is connected across a capacitor which is connected in series with an impedance across the ballast output winding.

Abstract: Starting and operating circuit for gaseous discharge lamps having device for quickly restarting extinguished lamps while still hot includes means for reducing power supply voltage overshoot upon turn-on of the system. 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 the lamp, a rectifier connected between the alternating current source and the oscillator circuit, the overshoot reducing means comprising a resistor connected between the rectifier and the oscillator circuit and a controlled switch for selectively connecting and disconnecting the resistor in the circuit.

Abstract: Static inverter comprises a transformer and transistor for intermittent asymmetric energization of the transformer. The transformer includes three feedback windings which in response to saturation of a branch of the transformer core but before full core saturation discontinue regenerative feedback and then apply degenerative feedback. A fourth feedback winding in the transformer assures commutation and re-triggering of the transistor.

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, the oscillator circuit comprising a transistor switch and an oscillator transformer connected to the step-up transformer for producing a high voltage, high frequency sine wave for starting and re-starting the discharge lamp. The operation of the oscillator circuit is improved by a turn-off circuit comprising series-connected diode and inductor connected to the transistor and the oscillator transformer.

Abstract: Gaseous discharge lamps of high pressure sodium vapor type having an arc tube containing a mixture of sodium vapor and another metal vapor are operated with unidirectional current (DC) pulses in a manner to avoid color separation of the light due to segregation of the atoms of the different metal vapors. The DC pulses are applied to the lamp with repetition rates of from about 50 Hertz to about 23,000 Hertz and a duty cycle of from about 8% to about 80%.

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.