US2939019A - Circuit arrangements for producing substantially constant currents - Google Patents

Circuit arrangements for producing substantially constant currents Download PDF

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Publication number
US2939019A
US2939019A US554074A US55407455A US2939019A US 2939019 A US2939019 A US 2939019A US 554074 A US554074 A US 554074A US 55407455 A US55407455 A US 55407455A US 2939019 A US2939019 A US 2939019A
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United States
Prior art keywords
core
current
winding
circuit
cores
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Expired - Lifetime
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US554074A
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English (en)
Inventor
Ridler Desmond Sydney
Grimmond Robert
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International Standard Electric Corp
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International Standard Electric Corp
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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
    • G05F1/10—Regulating voltage or current
    • G05F1/12—Regulating voltage or current wherein the variable actually regulated by the final control device is ac
    • G05F1/32—Regulating voltage or current wherein the variable actually regulated by the final control device is ac using magnetic devices having a controllable degree of saturation as final control devices
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B11/00—Automatic controllers
    • G05B11/01—Automatic controllers electric
    • G05B11/012—Automatic controllers electric details of the transmission means
    • G05B11/016—Automatic controllers electric details of the transmission means using inductance means
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11C—STATIC STORES
    • G11C19/00—Digital stores in which the information is moved stepwise, e.g. shift registers
    • G11C19/02—Digital stores in which the information is moved stepwise, e.g. shift registers using magnetic elements
    • G11C19/04—Digital stores in which the information is moved stepwise, e.g. shift registers using magnetic elements using cores with one aperture or magnetic loop
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F38/00—Adaptations of transformers or inductances for specific applications or functions
    • H01F38/02—Adaptations of transformers or inductances for specific applications or functions for non-linear operation
    • H01F38/023—Adaptations of transformers or inductances for specific applications or functions for non-linear operation of inductances
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K3/00—Circuits for generating electric pulses; Monostable, bistable or multistable circuits
    • H03K3/02—Generators characterised by the type of circuit or by the means used for producing pulses
    • H03K3/45—Generators characterised by the type of circuit or by the means used for producing pulses by the use, as active elements, of non-linear magnetic or dielectric devices

Definitions

  • the present invention relates to constant current sources.
  • a circuit arrangement for producing an electrical current of substantially constant amplitude which comprises a core of a ferro-magnetic material having a substantially rectangular hysteresis loop, which core is normally in a condition of remanence in one direction of magnetisation, a winding on said core, and means for applying a voltage across said winding in such a direction and of such a magnitude as to drive said core towards saturation in the other direction of magnetisation, whereby a current ofsubstantially constant amplitude flows in said winding while said core is changing its condition along the corresponding vertical porton of said loop towards saturation in the other direction of magnetisation.
  • Fig. l is an idealised hysteresis loop of a so-called square-loop ferro-magnetic material, the product of flux and time being plotted against the product of magnetisation and current, I
  • Fig. 2 is an idealised representation of how the current flowing in a coil wound on a core having a hysteresis loop such as that shown in Fig. l varies, current being plotted against time.
  • the inset to the figure shows the circuit.
  • Fig. 3 is a representation similar to Fig. 2 of the current flowing when the core has a secondary winding in which a load current can flow, the circuit being shown as an inset to the figure.
  • Fig. 4 is a circuit diagram of an extension of the principle exemplified in Fig. 3 wherein a winding on a second core is connected in series with the primary winding.
  • Fig. 5 shows how the load current in the circuit of Fig. 4 varies with the load resistance.
  • Fig. 6 shows three cores having primary windings interconnected in series, the secondary windings not being so interconnected. This circuit is used to produce a series of three staggered pulses in the three secondary windings.
  • Fig. 7 shows how the primary and secondary currents vary with respect to time in the circuit shown in Fig. 6.
  • the state of the core can be changed from negative remanence to positive saturation by applying a voltage of suitable polarity and amplitude across a winding on that core.
  • the current flowing in the winding rises almost instantaneously until the first knee 1 of the. hysteresis 2,939,019 Patented May 31, 1960 loop is reached, whereafter the current flowing remains substantially constant as the condition of the core negotiates the vertical portion of the hysteresis loop until the second knee 2 of the hysteresis loop has been reached. Thereafter the current commences to rise again, theoretically rising to infinity.
  • the current time relationship of the circuit is shown in the inset to Fig. 2.
  • the current is constant during the period of the kneeto-knee transition along the vertical portion of the loop because during this period the slope permeability of the core material changes from the very low value which applies at the remanence point to a very high value.
  • the duration of the constant current is given by t 10 secs.
  • n is the number of turns on the winding
  • gi is the remanent flux
  • saturation flux is the saturation flux
  • V is the applied voltage across the winding.
  • the core if the applied voltage is removed from the winding before the core has saturated, the core returns to negative remanence, so that the core acts as a constant current supply for the duration of the voltage across its winding.
  • the device will operate as a transformer and an will be induced in the secondary winding to which a load 4 may be connected. This will only be present while the flux is changing in the core, i.e. during the period of the knee-to-knee transition. As can be seen from the hysteresis loop shown in Fig. 1, there is little or no flux change before the first knee or after the second knee. Any current absorbed by the load 4 connected to the secondary winding 3 will then appear as an additional current flowing in the primary circuit, the value of this additional primary current being dependent on the primary-to-secondary turns ratio.
  • the core reverts to negative remanence so that the secondarywinding current is a pulse whose length equals the duration of the primary winding voltage.
  • the circuit shown in the inset to Fig. 2 has an additional winding *5 connected in series with a battery and a switch 6, so that when the switch 6 is closed a current flows through the winding in such a direction as to return the core to its negatively magnetised state. Hence when the switch 6 is opened, the core is left at negative remanence Fig. l.
  • a similar additional winding 5 is shown on the core in the inset to Fig. 3.
  • no provision for resetting would be needed it the circuit is so used that the core does not saturate.
  • blocking means for instance a rectifier 7, may be included.
  • the resetting could also, of course, be effected by a current flowing in the original or primary winding on the core in the opposite direction to the current causing the to transition.
  • the value of the load current can be limited by limiting the current flowing in the primary winding on the core.
  • a second core also having a rectangular hysteresis loop is used with a winding on it connected in series with the primary winding of the first core.
  • the second core is shown at 8, and the first core at 9.
  • the flux change in the second core is arranged to occur at a value of current at least equal to that which saturates the first core. This can be achieved, for example, by increasing the magnetic path length of the second core as compared with that of the first core, or by reducing the number of turns on the winding on the second core if the second core is to saturate at a higher current than the first core.
  • the time taken for the second core to change from one polarity of flux to the other is comparatively long. This can be achieved by increasing the cross-sectional area of the core.
  • both cores are returned to their original state, i.e. negative remanence, after each operation, for instance by the use of an extra resetting winding on each core, as shown in insets to Figs. 2 and 3, or by passing a reverse current through the series-connected windings on cores 8 and 9.
  • the resetting arrangements being similar to those used in the above-described circuits, are omitted from Fig. 4.
  • the assumption is further made that the voltage applied to the cores 8 and 9 is removed before the second core has had time to saturate.
  • the circuit produces, in the secondary winding on core 9, a pulse of current Whose duration depends on the characteristics of core 9, which pulse is of substantially constant amplitude for a wide range of load values.
  • Fig. 5 The relation between load resistance and load cur ent is shown in Fig. 5, and it will be seen that when theload resistance exceeds a certain value, the current commences to fall.
  • a possible application of the circuit of Fig. 4 would be the production from a master pulse of a pulse of shorter duration and of defined amplitude.
  • the first core 9 commences to traverse the vertical portion or" the loop at the current value at which the secondary current has the desired amplitude and that the time taken to traverse the vertical portion gives the duration of the desired pulse.
  • the second core 8 saturates at a current value equal to or greater than the first core and its time to traverse the vertical portion of its core exceeds the duration of the master pulse.
  • the arrangement shown in Fig. 6 is an extension of the principle of Fig. 4 to the production or" a series of three staggered pulses.
  • Such series of two or more pulses are used to operate certain varieties of pattern movement or shifting registers and counters.
  • These pulses can be produced by a series of cores 10, 11 and 12 respectively having their primary windings interconnected in series, with the secondary windings forming the separate outputs from the circuit.
  • the separate cores change over at successively higher values of current, and take successively longer periods to do this.
  • the current in the primary circuit has the characteristic shown in the upper portion of Fig. 7.
  • the broken lines show the open circuit current, while the solid lines show the currents which flow with the respective secondary windings feeding load circuits.
  • a core with winding such as core 8 in Fig. 4
  • cores 1t the cores 1t
  • 11 and 12 the cores 1t
  • resetting arrangements for the cores in Fig. 6 are necessary. These have been represented as a battery and switch in series with additional windings on the cores.
  • the core with its windings can be regarded as a switch which connects an output circuit connected to the secondary winding to the power supply for a defined period during which current flows in the output circuit.
  • a train of cores such as is shown in Fig. 6, can be regarded as a distributor interconnecting the power supply and the respective outputs singly and successively for defined periods.
  • a circuit arrangement comprising a first core of ferro-magnetic material, a second core of ferro-magnetic material having a substantially rectangular hysteresis loop, means for normally causing both said cores to assume a condition of remanence in one direction of magnetization, a primary winding on said first core, a secondary winding on said first core, a load circuit connected across said secondary winding, a primary winding on said second core connected in series with said primary winding on said first core, a source of voltage, the relative shapes of the hysteresis loop of said first and second cores being such that the primary ampereturns required to drive said first core from its remanent condition to a point of zero flux is less than that for said second core and the flux required substantially to saturate said first core is greater than that required to saturate said second core, and switch means for applying a voltage from said source to said primary windings of such polarity and magnitude as to drive said first and second cores towards saturation in the other
  • a circuit arrangement as defined in claim 1, in which the first core has a rectangular hysteresis loop, further comprising a secondary winding on the second core and a load circuit across said last-mentioned secondary winding, the characteristics of said cores being such that the transitions along the respective vertical portions of the hysteresis loops of said cores towards saturation in the secondary direction of magnetization commence at suc- 3.
  • a circuit arrangement as defined in claim 2, in which there are more than two cores each having a primary winding and a secondary winding and a load circuit connected across each secondary winding, the primary windings being connected in series, the characteristics of said cores being such that the transitions along the respective vertical positions of the hysteresis loops of said cores towards saturation in the second direction of magnetization commence at the same value of current but take inereasingly longer times, whereby the currents which flow in the secondary windings of said cores form a series of pulses which start at the same time but which have successively greater duration, each said pulse lasting for the period of transition of the respective core.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Power Engineering (AREA)
  • Nonlinear Science (AREA)
  • General Physics & Mathematics (AREA)
  • Automation & Control Theory (AREA)
  • Electromagnetism (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Inverter Devices (AREA)
  • Coils Or Transformers For Communication (AREA)
US554074A 1954-12-31 1955-12-19 Circuit arrangements for producing substantially constant currents Expired - Lifetime US2939019A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB37787/54A GB791905A (en) 1954-12-31 1954-12-31 Improvements in or relating to circuit arrangements for producing substantially constant currents

Publications (1)

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US2939019A true US2939019A (en) 1960-05-31

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US554074A Expired - Lifetime US2939019A (en) 1954-12-31 1955-12-19 Circuit arrangements for producing substantially constant currents

Country Status (7)

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US (1) US2939019A (fr)
JP (1) JPS324380B1 (fr)
BE (1) BE544067A (fr)
CH (1) CH352389A (fr)
DE (1) DE1057169B (fr)
FR (1) FR73322E (fr)
GB (1) GB791905A (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3054044A (en) * 1959-12-30 1962-09-11 Ibm Temperature sensing circuit
US3098157A (en) * 1957-12-23 1963-07-16 Kodusai Denshin Denwa Kabushik Logical element
US3204177A (en) * 1961-11-02 1965-08-31 Michel Adolf Keying devices, particularly for electrical musical instruments

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2375609A (en) * 1940-05-23 1945-05-08 Zuhlke Marcel Arrangement for protecting circuit breakers
US2719773A (en) * 1953-11-20 1955-10-04 Bell Telephone Labor Inc Electrical circuit employing magnetic cores
US2730694A (en) * 1951-02-02 1956-01-10 Ferranti Ltd Amplitude recording system utilizing saturable core reactors
US2758221A (en) * 1952-11-05 1956-08-07 Rca Corp Magnetic switching device
US2781504A (en) * 1954-12-17 1957-02-12 Olivetti Corp Binary system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2375609A (en) * 1940-05-23 1945-05-08 Zuhlke Marcel Arrangement for protecting circuit breakers
US2730694A (en) * 1951-02-02 1956-01-10 Ferranti Ltd Amplitude recording system utilizing saturable core reactors
US2758221A (en) * 1952-11-05 1956-08-07 Rca Corp Magnetic switching device
US2719773A (en) * 1953-11-20 1955-10-04 Bell Telephone Labor Inc Electrical circuit employing magnetic cores
US2781504A (en) * 1954-12-17 1957-02-12 Olivetti Corp Binary system

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3098157A (en) * 1957-12-23 1963-07-16 Kodusai Denshin Denwa Kabushik Logical element
US3054044A (en) * 1959-12-30 1962-09-11 Ibm Temperature sensing circuit
US3204177A (en) * 1961-11-02 1965-08-31 Michel Adolf Keying devices, particularly for electrical musical instruments

Also Published As

Publication number Publication date
FR73322E (fr) 1960-11-30
CH352389A (de) 1961-02-28
GB791905A (en) 1958-03-12
BE544067A (fr) 1900-01-01
JPS324380B1 (fr) 1957-06-29
DE1057169B (de) 1959-05-14

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