Abstract: An electronic controller for fluorescent lamps includes a DC to AC converter which supplies high frequency current to the lamps and a preconditioner stage which includes a switched mode power supply connected to accept line power and produce a DC input for the DC to AC converter. The switched mode power supply and the DC to AC converter are synchronized to operate in a fixed phase relationship and/or at the same frequency.

Abstract: A circuit arrangement suitable for operating a low pressure mercury discharge lamp by means of a high-frequency pulsatory current comprising circuitry for generating a high-frequency pulsatory current from a supply voltage with a modulator for modulating the high-frequency pulsatory current into a substantially square-wave shape voltage with a current amplitude A, with a modulation frequency f and a duty cycle DC together with circuitry for adjusting the duty cycle DC and circuitry for adjusting the amplitude A.

Abstract: The transformer comprises an annular core (1) of a soft-magnetic material on which there are provided a first winding and a second winding. The second winding comprises n turns more than the first winding. The first winding consisted of a first conductor (3) and a second conductor (5), the second winding consisting of a third conductor (7). The three conductors (3, 5, 7) are twisted over a part of their length so as to form a cable (9) wherefrom a common winding is formed which includes at least a part of the second winding and substantially the entire first winding. Near one end of the common winding there are provided n additional turns of the first conductor (3) and near its other end there are provided n additional turns of the second conductor (5). The corresponding end portions of the first and second conductors (3, 5) are electrically interconnected in order to form terminals (13, 19) of the first winding, and the end portions of the third conductor (7) form terminals (11, 15) of the second winding.

Abstract: An arrangement for use with gaseous discharge lamp circuits having a power factor capacitor in which the capacitor can be disconnected from the circuit when the lamp is not drawing current and in which an emergency lamp can be connected across a voltage source when the discharge lamp is not drawing current.

Abstract: A circuit arrangement for operating a discharge lamp includes a DC-AC converter provided with a branch A having at least one switching element alternately conductive and non-conductive for generating a current of alternating polarity at a frequency f. A load branch B is coupled to the branch A and is provided with lamp connection terminals and with inductive means. A drive circuit E renders the switching element conducting and non-conducting at a frequency f. The drive circuit is provided with a branch D which includes a series circuit of further inductive means and capacitive means, and with a branch C including a variable impedance. The drive circuit is coupled to the inductive means in the load branch B, the branch D is coupled to the switching element in branch A, and the branch C is coupled to the further inductive means in branch D. Branch C also includes inductive means and the variable impedance is a variable resistor. The lamp thus can be dimmed over a wide range by a simple and inexpensive circuit.

Abstract: An ignitor circuit for a gas discharge lamp includes a transformer and means for generating pulsatory voltages across a primary winding of the transformer to generate ignition pulses by means of a secondary winding of the transformer. The ignitor circuit further includes first means for measuring an amplitude of the ignition pulses, and second means for changing the pulsatory voltage across the primary winding, and thus changing the amplitude of the ignition pulses, in dependence on the measured amplitude of the ignition pulses. The ignitor circuit is capable of generating a suitable ignition pulse over a wide range of connection cable lengths.

Abstract: A circuit arrangement suitable for operating a low pressure mercury discharge lamp by means of a high-frequency pulsatory current comprising circuitry for generating a high-frequency pulsatory current from a supply voltage with a modulator for modulating the high-frequency pulsatory current into a substantially square-wave shaped voltage with an amplitude A, a modulation frequency f and a duty cycle DC together with circuitry for adjusting the modulation frequency f and circuitry for adjusting the duty cycle DC.

Abstract: A circuit arrangement suitable for operating a low pressure mercury discharge lamp by means of a high-frequency pulsatory current comprising circuitry for generating a high-frequency pulsatory current from a supply voltage with a modulator for modulating the high-frequency pulsatory current into a substantially square-wave shape voltage with a current amplitude A, a modulation frequency f and a duty cycle DC together with circuitry for adjusting the modulation frequency f and circuitry for adjusting the amplitude A and circuitry for adjusting the duty cycle DC.

Abstract: A circuit arrangement and a method suitable for operating a low-pressure mercury discharge lamp which includes circuitry for adjusting the average amplitude of the current provided to the lamp as well as circuitry for adjusting the modulation of the current provided to the lamp.

Abstract: The combination of a fluorescent lamp with a grid between its electrodes and control equipment for operating the lamp in an on condition and an off condition by the application of pulses to the grid.