US2818556A

US2818556A - Magnetic system

Info

Publication number: US2818556A
Application number: US524669A
Authority: US
Inventors: Arthur W Lo
Original assignee: RCA Corp
Current assignee: RCA Corp
Priority date: 1955-07-27
Filing date: 1955-07-27
Publication date: 1957-12-31
Anticipated expiration: 1974-12-31

Description

Dec. 31, 1957 ARTHUR w. LO

MAGNETIC SYSTEM INPUT SECOND 6* OURCE W28 Filed July 27, 1955 RESET PULSE sol/R05 FIRST INPUT PUL s5 sou/m: 14

FIRST //VPl/7' PULSE ONLY SECOND MPUT PULSE O/VA) F/IPJT AND SECOND M/Pl/T PULSES' INVENTOR. ARTHUR 1N. LEI

A TTORNf Y United States Patent MAGNETIC SYSTEM Arthur W. Lo, Elizabeth, N. 1., 'assignor to Radio Corporation of America, a corporation of Delaware Application July 27, 1955, Serial No. 524,669

'9 Claims. (CL 340-174) This invention relates to 'a magnetic system, and particularly to a system useful in controlling or switching electric signals.

An object of the present'invention is toprovide an improved magnetic system th'at is adapted to perform a logical-operation'in an improved manner.

Another object of the presentinvention is to provide an 'improvedand inexpensive magnetic system for switching magnetic signals.

Still another-object of the present invention is to provide an improved magnetic circuit that operates to furnish an output signal only when each one of a plurality of inputs is activated.

The above and [further objects of the present invention are carried out by providing a magnetic material having a rectangular hysteresis characteristic and having a plur-ality of apertures and windingsso a-rrangedthat an output signal is induced inanv output winding wound through two of these apertures only if aninput signal has been applied to both first and second input windings respectively wound th-rou-gh thesetwo apertures. Theinput signals may be applied simultaneously or successively in any order.

The features oftheinvention, as well as the invention itself, both as to ,itsorganizationand methodof operation, will :best be understood fromthefollowing description, when read .in connection with the accompanying drawing wherein:

'Fig. l is a schematic diagram of a magnetic system according to the invention employing a core of magnetic material having a pair of setting apertures and a reset a er u Fig. 2 is a cross-sectional view of the transfluxor .of Fig. 1 along. the line 2-2; and

Figs. 3a-3d are diagrams useful in explaining the operation of the system of Fig. 1. i

The magnetic system of .Fig. 1 has a multi-apertured magnetic device made from a magnetic material having a substantially rectangular hysteresis loop. The material is in the form of an annular core in Which'the central aperture12 is t-ermedherein a reset aperture. The

core 10 is preferably of uniform thickness. First and second apertures, termed herein the

setting apertures

14 and 16, respectively, are symmetrically "located in the material with respect to theaper-ture 12 and have their respective centers located along a horizontal (as viewed in Fig. l) center-line of the core 10, which is the section line 2- 2. The diameter of the reset aperture 12 is made larger than that of each of the setting apertures 14 and '16, respectively, for reasons describedhereinafter. The

diameter of the first and

second setting apertures

14 and 16 may beequal.

Between the periphery of the core 10 and the -

apertures

14, 12, '16 are legs '1, 2, 3, and 4, respectively The cross-sectional areasof the-legs 1 through 4 taken through thernost restricted portionof the material, conveniently alongthe center line 2-.-2, are equal. Thelegs :1 and 4include the material vbetween the peripherycf magnesium ferrite.

the core 10 and the inside walls of the apertures 14- and 16, respectively. The

legs

2 and 3 include the material between the inside surface of the reset aperture 12 and the inside surface of the

setting apertures

14 and 16, respectively.

A cross-sectional view of the core 10 taken along the center-line 2-2 is shown in Fig. 2. The thickness 2 of the device 10 may be uniform throughout. A suitable magnetic material may be, for example, manganese- Although the hysteresis loop may not be truly or completely rectangular, it is 'sufiiciently so forpractical purposes.

A reset winding 18 is wound through the reset aperture 12 by threadingthe reset winding'18, beginning with the terminal 18a, across the top surface of the core 10, then downwardly through the reset aperture 12, and then along the bottom surface of the core 10 to the terminal 18b. The terminals 18a and 18b of the reset winding 18 vare connected to a reset pulse source 20. First and

second setting windings

22 and 24 are wound through the first and

second setting apertures

14 and 16, respectively, in;a manner similar to the reset winding 18 beginning withthe terminals 22aand24a, respectively. The terminals 22a and 22b of the first setting winding 22 are connected to a first input pulse source 26; and the

terminals

24a and 24b of the second setting winding 24 are connected to a second input pulse source 28.

An output winding 30 is wound through the first and

second setting apertures

14 and 16. Beginning with one terminal 30a, the output winding 30 is passed across the top surfaceof the core 10, then threaded downwardly through the first-setting aperture 14, then across the bottom surface and upwardly through the reset aperture 12, then acrossthe top surface and downwardly through the second setting aperture 16, then across the bottom surface, then aroundthe edgeand across the top surface of the core 10 to the ,t erminal 30b. The output winding terminals 3 0,and 30b areconnected to a utilization device 32. Th efvariouswindings are shown herein as singleturn windings for simplicityof drawing. When desired multi-turn windings may be employed.

Each of the sources herein is preferably a constant current source suchas a pentodetype vacuum tube circuit. The sources are arranged to furnish a pulse of one-polarity, for example, positive, to the respective windin'gs. The respective directions of current flow (conventional) in windings 1'8, "2'2 and 24is indicated by the arrows adjacent thereto.

The operation "of the system of Fig. 1 maybe explained in connection with the diagrams'of Figs. 3a to 3d. There is an individual flux path about each of the apertures. *In addition to the individual flux ipaths, there exist three other longer flux paths which are presently of interest; two. of these-longer paths .13 and 15 are respectively about the resetaperture-IZ and the first setting aperture 14 and about the reset aperture 12 and the second setting aperture 16. {The third longer path (not shown) is about all three of the apertures.

For purposes of yexplanation of the operation of the system of Fig. 1, a particular one of the two possible states of saturation of a magnetic material produced by a current pulse is arbitrarily assumed to correspond to one sense of-tlux orientation along a closed flux path. Briefly, there are two senses of flux flow around a closed path. positive (conventional) current flow intersectingly through a surface bounded by the path produces a clockwise (as viewed from that side of the surface toward and through which the current flows) flux around the path linked bythe current. This rule corresponds to the so-called "right-hand rule. One state of saturation, with .reference to a closedpath, is that in which the saturating 3 other state of saturation, with reference to that path, is that in which the saturating flux is oriented in the opposite sense around the closed path.

One manner of operating the system of Fig. 1 is as follows: Assume that the reset pulse source 20 is operated to apply a positive reset pulse 34 to the reset winding 18. The amplitude of the reset pulse is made sufiicient to estabiish a clockwise saturating flux in each of the legs 1-4 around the reset aperture 12. The flux orientation in the respective legs, upon the termination of the reset pulse 34, is shown by the solid arrows of the diagram of Fig. 3a. Initially, the output winding 30 may be open-circuited so that any voltage induced therein by the reset pulse does not produce any current fiow.

Assume, now, that the first input pulse source 26 is operated to apply a positive setting pulse 36 to the first setting winding 22. This setting pulse produces a flux change in the legs 1 and 3 from the clockwise to the counter-clockwise sense around the first setting aperture No flux change is produced in the leg 2 because, in the reset condition, the leg 2 is already saturated with flux oriented in the counter-clockwise sense around the first setting aperture 14. The flux orientation, upon the termination of the setting pulse 36, is indicated by the arrows in the respective legs of the diagram of Fig. 3b. The dotted arrows indicate the changed flux caused by the setting pulse. No output voltage is induced in the output winding 30 by the first setting pulse 36 because the output winding 30 does not link either of the legs 1 and 3.

The amplitude of the setting pulse is made greater than a certain minimum value to achieve a complete flux reversal in all portions of the legs 1 and 3. This minimum amplitude depends upon the coercive force of the magnetic material employed and the radial distance of the outer portion of the leg 3 from the first setting aperture 14. For a core of given thickness and uniform coercive force, the minimum amplitude is essentially proportional to the radial distance of the leg 3 from the first setting aperture 14. The setting pulse, however, may be of an indefinitely large amplitude without producing any flux change in the leg 4. No flux change is produced in the leg 4 because all the fiux change of the leg 1 will be absorbed by the equal leg 3 before any flux change is produced in the leg 4. A new reset pulse 34 can be applied to the reset windmg 13 to return the core 10 back to the reset condition. The flux in the respective legs 14 is again oriented in a clockwise sense around the reset aperture 12. The new reset pulse does not induce any voltage across the terminals of the output winding 30 because the legs 1 and 3 are not linked by the output winding 30.

Assume. now. that the second input pulse source 28 is o erated to apply a positive setting pulse to the second i setting winding 24. This positive setting pulse produces flux change in the

legs

2 and 4 from the clockwise to the counterclockwise sense with reference to (that is,

a ound) the second setting aperture 16. No flux change is p duced in the leg 3 because the leg 3 is already saturated with flux in the counter-clockwise sense with referto the second setting aperture 16. No flux change is produced in the distant leg 1. because all the flux change in the leg 4 is absorbed by the near leg 3 before any flux change is produced in the distant leg 1. No net output voltage is induced in the output winding 30 because the output winding 30 links the

legs

2 and 4 in opposite senses and the individual voltages resulting from the flux changes in these legs cancel each other. Following the application of the second setting pulse 38, another reset pulse 34 can be applied to the reset winding 18, thereby returning the transfluxor 10 to a reset condition. The reset pulse still does not induce any voltage across the terminals of the output winding 30 because the

legs

2 and 4 are linked in opposite senses by the output winding 30. For example, the flux change in the leg'4 tends to make the terminal 30:: of the output winding positive, and the flux change in the leg 2 tends to make the terminal. 30:: negative. The induced voltages resulting from these separate flux changes are of opposite polarity, of substantially equal amplitude and cancel each other.

Assume, now, that the first input pulse source 26 is operated and then the second input pulse source 28 is operated. The flux orientation after the operation of the first input pulse source 26 is indicated in Fig. 3b by the arrows in the respective legs. Note that the flux in both the

legs

3 and 4 is oriented in the clockwise sense with reference to the second setting aperture 16. Accordingly, when the second input pulse source 28 is operated, a flux change from the clockwise to the counter-clockwise direction is produced in the

legs

3 and 4. No flux change is produced in the now distant leg 2 because the leg 3 absorbs all the-flux change produced in the leg 4. .The flux change produced in the leg 4 alone induces a voltage across the terminals of the output winding 30 which is applied to the utilization device 32.

A subsequent reset pulse returns the flux in the legs 1 and 4 back to the initial clockwise sense, with reference to the reset aperture 12. An output voltage is now induced across the terminals of the output winding 30 by the reset pulse. The latter output voltage is of an opposite polarity to that produced when the second setting pulse is applied to the second setting winding 24. If desired, the output voltage produced by the reset pulse can be prevented from causing a current flow by connecting, for example, a suitably poled unilateral conducting device (not shown) in series with the output winding 30.

Similarly, an output voltage is induced across the terminals of the output winding 30, when the first input pulse source 26 is operated subsequent to the operation of the second input pulse source 28. For example, assume that the system is reset. Activation of the second input pulse source 28 produces a flux change along the path 15. The changed flux in the

legs

4 and 2 is indicated by the dotted arrows of Fig. 3c in these legs. Note that the flux in the legs 1 and 2 about the first setting aperture 14 is now oriented in the clockwise sense, with reference to the first setting aperture 14. Thus, a subsequent setting pulse from the first input pulse source 26 reversesthe flux around the first setting aperture 14 from the clockwise to the counter-clockwise sense. The flux change in the leg 2 induces a voltage across the terminals of the output winding 30; and a signal is applied to the utilization device 32. No flux change is produced in the distant leg 3 because the leg 2 now absorbs all the flux change of thelegl.

A following reset pulse again changes the flux in the legs 1 and 4 back to the clockwise sense with reference to the reset aperture 12. Again, the flux change in the leg 4 induces a voltage across the terminals of the output winding 30 when the reset pulse is applied.

An output voltage is also obtained when the two setting pulses are applied simultaneously. In such case, there is a flux change in the legs 1 and 4 around the longer path about all three apertures. The flux orientation in the leg 3 is held in the counterclockwise sense, with reference to the second setting aperture 16, due to the magnetomotive force generated in this direction by the second setting pulse. Similarly, the flux in the leg 2 is held in the counter-clockwise sense, with reference to the first setting aperture 14, by the magnetomotive force in this direction generated by the first setting pulse. Therefore, only the flux in the legs 1 and 4 change. The output voltage results from the fiux change in the leg 4.

The output voltage and current depend somewhatupon the impedance of the utilization device 32. If the impedance of the utilization device is relatively low, a relatively large current flows in the output winding 30 when rent is in a direction to hold the leg -'3 saturated in the clockwise sensewith reference to the second setting aperture 16. Accordingly, some flux change is .produced in the second longer path 15 about the second setting aperture 16 and the blocking aperture 12, thereby bypassing some of the flux change-produced in the leg 4 to the distant leg 2. The flux change along the second longer path 15 does not add to the outputsignal and, therefore, the output signal is reduced by a corresponding amount. If the utilization device has a-high impedance, most of the flux change is produced in the path about only the second setting aperture 16 including the

legs

3 and 4. The flux loss is reduced somewhat by making the diameter of the blocking aperture 12 larger than that of the setting

apertures

14 and 16. In many applications, the flux loss resulting from the flux change about the longer path 15 is unimportant, vfor example, ,when the device ,10 is operated as a digital device.

Instead of returning the output winding 30 across the top surface of the core to the terminal 30b, the output winding can be returned along the bottom surface of the core .to .the terminal 30b. In this case the legs 1 and 3 are-linked bythe output winding. The roles of the

legs

1 and 3, and 2 and 4 are interchanged. Otherwise, the operation of the device '10 is the same and no output signal 'isapplied to the utilization device32 unless both the first and the secondinput pulse sources have been operated.

There has been described herein an improved magnetic system for switching electric signals by means of a multiapertured magnetic core. The system of the present in vention operates as a logical and gate circuit. That is, no output signal is produced unless both inputs have been activated. The inputs may be activated simultaneously or sequentially in any desired order. Other shapes than the annular core described may be employed so long as the relationship between the respective legs and the manner of linking the output winding is preserved.

What is claimed is:

l. A magnetic device comprising a body of magnetic material having two stable remanent states, said body having first, second and third apertures and a plurality of legs therein, a first and a second of said legs respectively being defined by the material between the outside edge of said body and the inside surface of said first and second apertures, and a third and fourth of said legs respectively being defined by the material between the inside surface of said third aperture and the inside surface of said first and second apertures, a first winding means wound through said third aperture for establishing flux in one sense in all of said legs with respect to said third aperture, separate second and third winding means respectively wound through said first and second apertures, and a fourth winding means linking one of said first and second legs and one of said third and fourth legs, whereby a signal is induced in said fourth winding means only when said second and said third winding means have received excitations.

2. A magnetic device comprising an annularly shaped core of magnetic material having two stable remanent states, said core having a central aperture, said core having at least two other apertures each through a portion of the material between the inner and outer radial dimensions thereof, first and second windings respectively wound through separate ones of said other apertures, and another winding wound through said other apertures and linking a portion of the material adjacent each of said other apertures, said other winding serving as an output for the device, whereby an output signal is produced only when said first and second windings have received signals.

3. A magnetic device comprising a body of magnetic material having two stable remanent states, said body having first, second and third apertures and a plurality of legs therein, a first and a second of said legs respectively being defined by the material between the outside edge of said body and the inside surface of said first and second apertures, and a third and fourth of said legs respectively being defined by the material between the inside surface of said third aperture and the inside surface of said first and second apertures, said first and second apertures being so located in said body that the crosssectional areas at the most restricted portion of the first and second of said legs are substantially equal to each other, a first winding means wound through said third aperture for establishing a fiux in one sense in all of said legs with respect to said third aperture, separate second and third winding means respectively wound through said first and second apertures, and a fourth winding means wound through both said first and second apertures, whereby a signal is induced in said fourth winding means only when said second and third winding means have received excitations.

4. A magnetic device comprising a body of magnetic material having two stable remanent states, said body having first, second and third apertures and a plurality of legs therein, a first and a second of said legs respectively being defined by the material between the outside edge of. said body and the inside surface of said first and second apertures, and a third and fourth of said legs respectively being defined by the material between .the inside surface of said third aperture and the inside surface of said first and second apertures, said apertures being so located in said body that the cross-sectional area at the most restricted portions of said third and second legs is at least equal to the cross-sectional area at the most restricted portions of said first and fourth legs, respectively, a first winding means wound through said third aperture for establishing a flux in one sense in all of said legs with respect to said third aperture, separate second and third winding means respectively wound through said first and second apertures, and fourth winding means linking only two of said legs, whereby a signal is induced in said fourth winding means only when said second and said third winding means have received excitations.

5. A magnetic device comprising an annularly shaped core of magnetic material having two stable remanent states, said core having a central aperture, said core having at least two other apertures each through a portion thereof between the inner and outer radial dimensions thereof, the inner radial dimension of said core being substantially greater than the dimensions of any one of said other apertures, separate first and second windings wound respectively through a first and a second of said other apertures, a third winding wound through said first and second apertures exclusively, said third winding serving as an output winding for the device in which an output signal is produced only when said first and second windings have received signals.

6. A magnetic device comprising a body of magnetic material having two stable remanent states, said body having first, second and third apertures and a plurality of legs therein, a first and a second of said legs respectively being defined by the material between the outside edge of said body and the inside surface of said first and second apertures, and a third and fourth of said legs respectively being defined by the material between the inside surface of said third aperture and the inside surface of said first and second apertures, a first winding means wound through said third aperture for establishing a flux in one sense in all of said legs with respect to said third aperture, second and third winding means respectively wound through said first and second apertures, and a fourth winding means wound through said first and second apertures so as to link only said second and third legs, whereby a signal is induced in said fourth winding means only when said second and said third winding means have received excitations.

7. A magnetic device comprising a body of magnetic material having two stable remanent states, said body having first, second and third apertures and a plurality of legs therein, a first and a second of said legs respectively being defined by the material between the outside edge of said body and the inside surface of said first and second apertures, and a third and fourth of said legs respec' tively being defined by the material between the inside surface of said third aperture and the inside surface of said first and second apertures, a first winding means wound through said third aperture for establishing a fiua in one sense in all of said legs with respect to said third aperture, second and third winding means respectively wound through said first and second apertures, and a fourth winding means wound through said first and second apertures 80 as to link only said second and third legs, whereby a signal is induced in said fourth winding means only when said second and said third winding means have received excitations.

8. A magnetic device comprising a unitary core consisting of magnetic material characterized by having a substantially rectangular hysteresis loops, said core having a central aperture and at least two other apertures each through a portion thereof between the inner and outer radial dimensions thereof, separate first and second windings respectively wound through first and second ones of said other apertures, and a third Winding wound through said first and second apertures exclusively, said third 8 winding, serving as an output winding for the device in which an output signal is produced only when said first and second windings have received signals.

9. Arnagnetic device comprising a unitary core consisting of magnetic material characterized by having a substantially rectangular hysteresis loop, said core having a central aperture and at least two other apertures each through a portion thereof between the inner and outer radial dimensions thereof, separate first and second windings respectively wound through first and second ones of said other apertures, and a third winding having first and second terminals, said third winding being wound so as to link only the material between said central and first apertures and the material between said second aperture and the periphery of said core, said third winding serving as an output winding for the device in which an output signal is produced only when said first and second windings have received signals.

References Cited in the file of this patent UNITED STATES PATENTS 2,284,406 DEntrernont May 26, 1942 2,519,425 Barlow Aug. 22, 1950 2,519,426 Grant Aug. 22, 1950 2,614,167 Kamm Oct. 14,1952 2,640,164 Giel et al. May 29, 1953 2,708,219 Carver May 10, 1955 of the above numbered patent requiring c U. Sr DEPARTMENT OF COMMERCE PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 2,818,556 Arthur W. Lo December 31, 1957 It is hereby certified that error appears.in the printed specification orrection and that the said Letters Patent should read as corrected below.

Column 7, line 1, beginning with "7. A magnetic" strike out all to and including "excitations," in line 19, same column; line 20, for the claim number "8," read --ZP; line 22, for "loops" read --loop--; column 8, line 4, for the claim number "9." read -8.---

in the heading to the printed specification, line 6, for "9 Claims" read --8 Claims--o Signed and sealed this let (1a; of July 1958,

(SE Attes KARL H. AXLINE ROBERT C. WATSON Attestlng Officer Commissioner of Patents U. 8.. DEPARTMENT OF COMMERCE PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 2,818,556 Arthur W. Lo December 31, 1957 It is hereby certified that error appears .in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column "7, line 1, beginning with "'70 .A magnetic" strike out all to and including "excitations." in line 19, same column; line 20, for the claim number "80'! read ---'7d-=-;' line 22, for "loops" read .--loop--; column 8, line 4, for the claim number "9." read 80-; in the heading to the printed specification, line 6, for "9' Claims" read --8 Claims- Signed and sealed this 1st as; of July 1958.,

Q (SE Attes KARL H. AXLINE ROBERT C. WATSON Attesting Officer Comnissioner of Patents