Space Systems/loral, LLC

Ford Aerospace & Communications Corporation

Power Spectra, Inc.

Richard A Williams

Stephen J Davis

Larry O Ragle

William L Jolitz

A high voltage high power fuse (5) for use in a low pressure environment such as space. The fuse (5) comprises a fuse element (1) which is electrically connected to two conductive pads (2) and surrounded by an elastic medium (3). When the fuse element (1) is vaporized by a current surge, the elastic medium (3) absorbs the energy of the explosion and then snaps back into the space (6) left by the vaporized fuse element (1). This action of the elastic medium (3) effectively quenches any electric arc which may have bridged the gap (6) between the ends of the blown fuse element (1).

High voltage high power arc suppressing fuse

A switch using an improved method of optically-triggered avalanche breakdown which can produce pulses of 100 picoseconds or longer duration that can deliver five kilovolts into 50 ohms using a standard laser diode. A semiconductor block is provided with contacts on opposing sides across which a high-voltage less than the avalanche breakdown voltage is applied. One of the electrodes is on a mesa on one side of the block. The mesa is then irradiated with electromagnetic radiation. The wavelength of the radiation and the absorption coefficient of the semiconductor block are chosen so that the absorption depth of the majority of the radiation is less than the distance between the contacts. This results in a conduction area where absorption occurs, thus applying most of the high voltage across the distance beyond where the radiation is absorbed. This provides field compression and generates an avalanche breakdown field across the remaining distance of the semiconductor block.

Bulk avalanche semiconductor switch using a mesa structure

A conformal coating protects electrical components used in a high voltage high vacuum evironment from flashovers caused by patch charging. The coating comprises a semiconductor powder, preferably elemental boron, having a low atomic number and uniformly dispersed throughout an organic binder such an an epoxy. The coating's surface resistivity is made to be high enough so that the coating acts as an electrical insulator. On the other hand, the coating's surface resistivity is sufficiently low that any patch charge is siphoned off to the nearest conductor. The surface resistivity is regulated by the proportion of semiconductor present. The coating's secondary electron emission coefficient is 1 or just under 1. The coating has the properties of adhesion, stability, elasticity, provision of mechanical support, and resistance to solvents and heat. An example is given in which the epoxy comprises resin, fine particles of elemental boron, and a polyamide hardener. The epoxy is mixed with solvents and sprayed or brushed onto the electrical components being protected, in this case a satellite TWTA EPC.

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Palo Alto, CA, United States of America

Richard A Williams