Abstract: A ballast safety circuit is disclosed. The ballast safety circuit includes a sensor in the form a toroid that includes a pair of coil windings for coupling to a pair of input lines on an input side of a ballast. The toroid further includes a third coil winding for detecting a leakage current flowing through one of the input lines when a person is attempting to mount a lamp on the ballast. Upon detection of the leakage current, the ballast safety circuit impeded an operation of the lamp to thereby dissipate the leakage current whereby the person can safely complete the mounting of the lamp on the ballast.

Abstract: A DC-DC voltage converter comprises a controller, two switches, a transformer and two rectifying diodes. The transformer has a first winding, a second winding and a center tap. Input voltage in connected between the center tap and ground. An anode of each diode is connected to the outer ends of the two windings and the cathodes of the two diodes are connected together to provide a positive output with respect to ground. Each switch is connected between an outer end of one windings and ground. The controller generates control signals to turn the switches on and off for limited periods of time in phase opposition to alternately connect the outer ends of the first and second winding to ground to cause current to flow alternatively in one of the windings and induce a voltage in the other winding that is additive to the input voltage, thereby providing an output voltage greater than the input voltage.

Abstract: This invention relates to a supply device for discharge lamps, which comprises, for each lamp:

Abstract: An electronic ballast for at least one low-pressure discharge lamp contains an inverter which is connected to a direct-voltage source (UBUS), a load circuit which is connected to the inverter and contains the lamp (LA) and a series resonant circuit, and an evaluating circuit arrangement (M1) which reacts to different operating states of the lamp (LA) and in the case of a defect or removal of the lamp (LA) generates corresponding signals which are used to switch off the inverter. Provided for the purpose of heating the coils (W1, W2) there is a heating transformer, the primary winding (Tp) of which is connected in series with a switch (S3) to the output of the inverter and in any case is connected to the direct-voltage source (UBUS) if the inverter is switched off on account of the heating-coil defect or the removal of the lamp (LA), with the switch (S3) being clocked in this off-phase.

Abstract: An improved voltage reduction apparatus specifically designed to overcome implementation problems of a prior art voltage reduction apparatus. The present invention is designed to overcome the problem of magnetic field flux induced harmonic distortion and heating associated with the prior art which otherwise substantially detracted from the advantageous implementation thereof. More specifically the present invention, also provides a highly advantageous apparatus for reducing voltage to a load, after first providing a full magnitude of voltage thereto by the use of an autotransformer having a series winding and a common winding disconnectable and connectable to one another by means of a relay or other equivalent switching device. However it also provides a bucking coil winding in parallel with the common winding and wound in bifilar opposed relation thereto.