Abstract: A collapsible, high voltage electrical discharge generator uses a set of telescoping winding sections to achieve a compact form suitable for efficient transport, storage and deployment. The winding sections have two typical arrangements, fully collapsed and fully extended. In the fully collapsed mode the sections can be telescoped together into a nested configuration, thus occupying a small fraction of the volume of a fully extended system. The towers can be erected into the fully extended mode by applying internal pressure, or alternatively by using mechanical linkage to simply extend the telescoped stack of winding sections into position. Fully extended and connected, the individual sections perform as a large, continuous inductive element capable of generating very high voltages at the top of the tower for use in testing equipment and producing long electrical discharges.

Abstract: A pulse width modulated half bridge dimming controller is provided for dimming a lighting ballast is described. The top half of the bridge is comprised of two switches, the top switch set, and the bottom half of the bridge is comprised of two switches, the bottom switch set. Each switch also has a diode in parallel with it. The drivers for the switches are configured so that each of the switches can be turned on and off independently of all of all the other switches. Preferably, the controller is capable of operating in all four quadrants. In one preferred embodiment the switches are IGBTs. The switches are controlled in a manner so that when one of the switches sets changes states, the second switch set has one switch on and one switch off, so that one of the diodes in the second switch set is disposed to block shoot through and provide a path to allow current to continue flowing in the inductive load.