Abstract: Power supply apparatus is disclosed which can be configured as a power line filter or an uninterruptible power supply having a battery test on load capability. It comprises an input reversible rectifier connectable between an AC supply and a high voltage internal DC bus, a second reversible rectifier interconnecting storage batteries to the high voltage DC bus, and an output module supplying a desired DC output or an AC output. In use the voltage on the internal DC bus is maintained at a greater level than that of (a) the instantaneous repetitive peak of the incoming voltage, and (b) the peak battery storage voltage. Battery test means is provided by allowing the dumping of the charge stored within the storage batteries for a certain period at the maximum available rate into the internal bus and back into the AC supply through the said reversible rectifiers; meanwhile observing the extent of the battery voatage drop so caused.

Abstract: A circuit suitable for the instantaneous starting, continuation, and interruption of current through one or more gasfilled discharge tubes, in particular fluorescent lamps, is described. The circuit and lamp heaters are energized before instantaneous control can occur. One preferred silicon controlled rectifier (SCR) is used with a bridge rectifier. The SCR has the dual role of causing the capacitor to discharge through the pulse transformer, the secondary pulse voltage of which thereby causes the arc to strike immediately upon application of gate current, and then maintianing the lamp current as long as a supply of SCR gate current is provided. A second preferred control device, a TRIAC, is used without a bridge rectifier and again has a dual role of pulse-starting and maintaining current. This type of device is more conveniently arranged to provide for a dimming function as well. Applications include "flashing" advertising signs, general illumination, and signals.