Arc discharge lamps driven at frequencies in excess of 20 kHz may exhibit the phenomenon of `acoustic resonance` in which longitudinal and lateral acoustic waves are supported in the arc tube. This is a problem because the acoustic wave may give rise to an instability in the discharge arc, causing it to stretch or gyrate and invariably to extinguish. In some cases damage may be caused to the arc tube. A power supply suitable for an arc discharge lamp comprises a drive circuit arranged to supply ...

An inverter power supply with improved power factor comprises a source of low frequency AC voltage and an inverter having a pair of series connected first and second transistors controlled to alternately turn on and off at a high frequency for providing a high frequency AC voltage to a load. A diode-bridge full-wave rectifier is connected to provide a DC voltage which is charged to at least one capacitor which in turn provides a DC voltage input to the inverter. An inductor, which counteracts th...

An electrical power supply system of the kind in which an input alternating voltage or current is rectified in a rectifier circuit (II) and the output is fed to a load (8) via a smoothing filter (III). The combination of the smoothing filter and load are arranged so that the input impedance of the smoothing filter is substantially real for the overall frequency spectrum applied thereto and has substantially the same value for each component of this spectrum thereby reducing distortion of the cur...

A battery pack is selectively connectable to electrical equipment and to a battery charger. The electrical equipment or battery recharger decides whether the attached battery pack is a compatible device. If the attached battery pack is determined to be suitable, electrical power is transferred from the battery pack to the electrical equipment or from the battery recharger to the battery pack. To determine whether the battery pack is compatible, the electrical equipment or battery recharger recei...

A supply system for supplying a liquid reagent from a storage tank to a dispensing head, for example a foam molding head, includes a tank (12) having a lid (14) moveable between a closed position and an open position affording access to the interior of the tank and the underside of the lid, a pump (26) and a distribution valve (36) disposed on the underside of the lid, and a drive motor (27) for the pump and an actuator (37) for the valve on the exterior of the lid. Any leakage occuring in use f...

A power supply wherein the rectified output of two or more transformer secondaries are connected in series and then parallel each half cycle of an alternating current energization signal. Logic circuitry monitors the rectified output and automatically switches from a series to a parallel connection to provide a regulated power supply output.

A supply caddy having a main body portion defining a pocket which is selectively subdivided by vertical and horizontal strips which are repositionable within the pocket. The caddy may be attached to a wearer by a strap.

A power supply unit has an overdischarge detection circuit for detecting overdischarge of a power source, an overcurrent detection circuit for detecting overcurrent, and a stopping circuit for stopping overdischarge or overcurrent in accordance with an overdischarge detection signal or an overcurrent detection signal. The power supply unit is further provided with a delay circuit to prevent the overdischarge detection circuit and the overcurrent detection circuit from being activated erroneously...

A supply unit for supplying a workplace with electricity and/or gaseous media, with a first, vertically extending supply duct and a second, vertically extending supply duct, wherein the electricity and the media are led to connections on at least one of the supply ducts. From these connections the workplace is supplied and improved such that the ergonomically most favorable arrangement of the supply tubes and electric lines leading to the connections will be possible. This object is accomplished...

A power supply apparatus has a rectifier for outputting a non-smoothed DC. A switching circuit alternately shut off output of the rectifier at a high frequency, which includes first and second switches. A first capacitor couples to the first and second switches for smoothing output of the rectifier. A series resonance circuit includes a second capacitor and an inductor so that the voltage across the first capacitor becomes lower by the resonance voltage than that of the output of the rectifier. ...