Hirst Magnetic Instruments Limited

Newage International Limited

The Moving Picture Company Inc.

Edwards Limited

John Dudding

Roland Grossinger

Peter K Shreck

Robin Nathan Cornelius

Geraint Jewell

A method of magnetizing members of magnetizable material () including presenting a magnetizer head to a circular array of the members () mounted on a rotor plate () of an electrical machine. The magnetizer head includes a circular array of coils (), each coil () being positioned adjacent a respective one of the members (). A current is supplied to selected juxtaposed pairs of the coils () so as to set up a magnetic field. Flux of the field forms a closed loop through the pair of coils () and the adjacent pair of members (), such that uncontrolled flux leakage from this loop is minimized and such that the pair of members () are at least partially magnetized.

Method of and an apparatus for magnetising a plurality of adjacent portions of magnetisable material

Characterisation of magnetic materials via a pulsed, field strength

Apparatus for testing the response of a viewer to questions or problems displayed on a video screen comprises apparatus to modulate the video signal to display coded patches on the screen. The patches are coded by alternately raising and lowering the luminance signal of the video without destroying spacial variations of the signal in the patch. The coding is detected by a probe having a light guide pointer conducting light from the video screen to a photo-detector in the casing of the probe. The coded luminance variations are read by the probe and produce response indications such as sound or light signals which qualify the response. The apparatus is useful as a teaching aid.

Video response testing apparatus

Growing community of inventors

Falmouth, United Kingdom

John Dudding