Abstract: Described is a ground loop locator. A readout on the ground loop locator indicates the presence of a ground loop when a ground loop exists in conductors linked by a current transformer of an exciter portion and a Rogowski coil of a detector portion. Also described are how to make and use the ground loop locator and methods of use for the ground loop locator.

Abstract: Described is a ground loop locator. A readout on the ground loop locator indicates the presence of a ground loop when a ground loop exists in conductors linked by a current transformer of an exciter portion and a Rogowski coil of a detector portion. Also described are how to make and use the ground loop locator and methods of use for the ground loop locator.

Abstract: This disclosure relates to a design for the circuit required to drive electrostatic loudspeakers. Such speakers require a high voltage audio signal, typically generated using a wideband, high power step-up transformer. The design eliminates the requirement for such a transformer by mixing the audio frequency signal with a high frequency carrier. This modulated signal may then be amplified and transformed to a high voltage signal using a much more modest transformer operating at the carrier frequency. A simple detection circuit then recovers the original audio waveform from the modulated signal and drives the electrostatic loudspeaker. Such a circuit may be cheaper than a wideband transformer and may also improve the frequency response of the driving electronics.

Abstract: The present invention provides a system for recording images occurring both before and after a triggering event. Temporarily stored images are continually refreshed, the most recent images replacing the oldest images, providing a continuously updated history of recent events in a memory configured as an endless loop. Upon receipt of an external trigger, a predetermined further quantity of temporary images are stored until the capacity of the temporary storage medium is reached and then all temporarily stored images are then permanently stored. The system includes a rotating polygon mirror which produces a sequence of image scan lines. A lens system focuses the scan lines onto a linear array of photodetectors. Transient digitizers or a CCD linear storage array temporarily stores image data received from the photodetectors. Upon receipt of a trigger, the temporarily stored images are transferred to permanent digital memory after a predetermined further quantity of images have been stored.

Abstract: Stabilizing the arc in an electric arc furnace is achieved by using a method and apparatus for applying a magnetic field parallel to the arc between the furnace electrodes. The magnetic field strength applied by the invention should exceed (h.mu.oI)/(2.pi..sup.2 a.sup.2) where h is the distance between the electrodes, a is the radius of the arc, I is the current between the electrodes and .mu.o is the permeability of free space. The magnetic field may be induced by any means not susceptible to the heat of the furnace, such as a coaxially positioned induction coil or by inducing a magnetic field in an open magnetic ring the ends of which form the furnace electrodes.