Patent GB-1027133-A (GB)
Title: Multi-aperture magnetic cores
IPC: G10C3/16
Filed: 1964-08-26
Abstract: 1,027,133. Circuits employing bi-stable magnetic elements. AMP Inc. Aug. 26, 1964 [Aug. 30, 1963], No. 34850/64. Heading H3B. [Also in Divisions G4 and H1] A multi-aperture magnetic core comprises first and second major apertures 14, 38 (Fig. 3), and at least two minor apertures 16, 40, 18, 42, the major apertures being separated by a core leg LC which has a cross-section sufficiently large to ensure that the core material around either aperture can be driven from its clear state (in which all the remanent magnetic flux around that aperture is polarized in one sense) to its set state (in which part of the flux around that aperture is polarized in one sense and part in the opposite sense) and vice versa without any substantial interaction with the remanent magnetic flux around the other aperture. The core may be wound to form a bistable flip-flop circuit by connecting together its input winding 50 and its output winding 54 so that in response to the energization of the advance windings 60, 62 and priming winding 64 the core portions around the apertures 14 and 38 are alternately driven between their clear and set states. Alternatively, two or more devices 10a, 10b may be connected to form a shifting register in which an input in winding 50 produces the set state (a " 1 ") (Fig. 4B) around aperture 14 and a limited priming pulse in winding 64 (which may link 16 and 42 with three turns) reverses flux about minor aperture 16 (Fig. 4C). Advance pulse IAO (Fig. 4D) in advance winding 60 then produces the cleared state around aperture 14, the change in flux direction in the core material outside aperture 16 producing pulse IF (Fig. 4E) in winding 52 (which may have two turns linking 16) which produces the set state around aperture 38 thus transferring the " 1 " thereto. The state of the core may be indicated by read-out windings linking apertures 40. The priming winding 64 is energized a second time to reverse the polarization of flux about the lower right-hand aperture 42 (Fig. 4F). A pulse IAE (Fig. 4G) in advance winding 62 then returns core portion 36 to its cleared state so that a pulse 1R (Fig. 4H) is produced in transfer winding 54 which links the lower left-hand aperture to the next device 10b so that the " 1 " is transferred to the portion 12 of device 10b by the production of the set state therein. The advance windings have holding portions linked with minor apertures in those portions of the cores which they are not intended to change from the set to the cleared state. In another arrangement (Fig. 5, not shown), the advance windings are connected to a common assist and hold winding 85 which gives increased outputs in the transfer and output windings in addition to its holding functions. The inlet winding 50 may be wound through the minor aperture 18 instead of the major aperture 14 and the crosssectional area of the legs L4, L5 about this aperture (Fig. 6, not shown), may be greater in total than the cross-sectional area of the main legs L to reduce the undesired switching resulting when a " 0 " signal (which should be zero but usually is not) is applied to a core portion which is already in a " 0 " state. Devices having cores with all the minor apertures of the same (small) size may be used in a shift register not having hold windings (Fig. 7, not shown). In another arrangement the core of the device has four major apertures (Fig. 8) the information written in by input winding 146 being transferred in succession to the core parts around various main apertures and then to output winding 154 by transfer windings such as 148, 150, 152. The advance windings (192, Fig. 9, not shown) may have no " hold " portions. The various apertures may have individual read-out windings for indicating the states of the core portions. There may be a central minor aperture 185 (Fig. 9, not shown), through which may pass a winding for presetting one or more core portions. In a shift register the devices may be arranged in one column.