Abstract: A magnetic head for reading or writing information magnetically encoded on a substrate is disclosed. Included in the head are a magnetic core and a boron carbide contact surface which the substrate rubs against during reading or writing. The boron carbide contact surface is electrically conductive and is resistent to wear. Grounding of the conductive boron carbide contact surface avoids static electric charge build up on the contact surface caused by rubbing of the substrate against the magnetic head.

Abstract: Unprocessed video signals from an optical scanner are processed in accordance with a transfer function which adjusts the gain of the unprocessed video to produce processed video which better represents the form of the object scanned. The transfer function is selected from a memory including a plurality of such functions by a signature signal which characterizes the entire scanner system including the optical system, the illumination system and the sensor system. The signature signal is developed from an initial value of signature which is updated by processing with the unprocessed video.

Abstract: Disclosed is a foldable circuit assembly 10 which has eight support members 11 having windows 12 in which circuits are bonded. The support members are all interconnected by a flexible polyimide web and an electrical circuit is etched thereon so as to interconnect the circuits and the external world via a contact tab extending from one of the support wafer members 11.