US2302893A - Variable inductance arrangement - Google Patents

Variable inductance arrangement Download PDF

Info

Publication number
US2302893A
US2302893A US297032A US29703239A US2302893A US 2302893 A US2302893 A US 2302893A US 297032 A US297032 A US 297032A US 29703239 A US29703239 A US 29703239A US 2302893 A US2302893 A US 2302893A
Authority
US
United States
Prior art keywords
radio frequency
control
variable inductance
flux
coil
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US297032A
Inventor
Walter Van B Roberts
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
RCA Corp
Original Assignee
RCA Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by RCA Corp filed Critical RCA Corp
Priority to US297032A priority Critical patent/US2302893A/en
Application granted granted Critical
Publication of US2302893A publication Critical patent/US2302893A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F21/00Variable inductances or transformers of the signal type
    • H01F21/02Variable inductances or transformers of the signal type continuously variable, e.g. variometers
    • H01F21/08Variable inductances or transformers of the signal type continuously variable, e.g. variometers by varying the permeability of the core, e.g. by varying magnetic bias
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F29/00Variable transformers or inductances not covered by group H01F21/00
    • H01F29/14Variable transformers or inductances not covered by group H01F21/00 with variable magnetic bias
    • H01F2029/143Variable transformers or inductances not covered by group H01F21/00 with variable magnetic bias with control winding for generating magnetic bias

Description

Nov. 24, 1942. w. VAN B. ROBERTS 2,302,393

VARIABLE INDUCTANCE ARRANGEMENT Filed Sept. 29, 1959 2 Sheets-Sheet 1 0 Eyd SOURCE F IRE CURRENT 0K WLY VARY ('0 0L CURRENT ENTOR WA L TER B. ROBERTS ATTORNEY Nov. 24, 1942. w V ROBERTS 2,302,893

VARIABLE INDUCTANCE ARRANGEMENT I Filed Sept. 29, 1939 2 Sheets-Sheet 2 .9 4 r0 PUSH-PULL Rf. SELECTOR .12 A F. GRIDS AND AMPL/F/ER AAA AAAA vvy vvv qllp FREQl/fA/CY CONVERT 5k AL 1. F. AMPL lF/ER v INVENTOR WALTER VAN B ROBERTS ATTORNEY Patented Nov. 24, 1942 2,302,893 VARIABLE INDUCTANCE ARRANGEMENT Walter van B. Roberts, Princeton, N. J., assignor to Radio Corporation of America, a corporation of Delaware Application September 29, 1939, Serial No. 297,032

1 Claim.

It has been proposed to vary the inductance of a coil having a magnetic core by superposing on said core a controlling flux which is adjustable in accordance with the inductance desired. However, if the coil carrying the controlling current is coupled to the radio frequency winding losses will be produced in the radio frequency winding. The present invention provides a construction which permits both the radio frequency coil and the control current winding to produce flux in a common portion of their magnetic circuits without thereby introducing any coupling between the two coils provided that the one coil carries radio frequency current and the other coil only direct or slowly varying current.

In the drawings:

Fig. 1 shows a variable inductance embodying the invention,

Fig. 2 is a modification,

Fig. 3 shows a radio receiver circuit employing the variable inductance device at the antenna circuit,

Fig. 4 shows a superheterodyne receiver employing the variable inductance device for automatic frequency control.

Fig. 1 shows one form of the invention where l represents a high frequency core made up of a material such as powdered iron and where the dotted lines 2 bearing arrows indicate the magnetic lines of force produced by current in the radio frequency coil 3. The core I is provided with a cylindrical copper shield 4 which surrounds the magnetic core 3 and this shield prevents radio frequency variations of magnetic flux from getting outside of the shield. Member 5 which is made of ordinary iron has mounted thereon control windings 6 and I. This arrangement forms a magnetic circuit which is completed by the magnetic material inside the shield 4. Typical lines of flux are shown by lines 9 and Ill. Due to the fact that the control flux represented by lines 9 and I0 is at most only slowing varying the copper shield 4 is ineffective to prevent the control flux from passing through the shield and acts merely like a small air gap. It will be noted that in addition to its primary purpose of preventing the radio frequency field from linking the control winding or the solid iron portion of the control circuit, the shield also acts in the usual way to prevent coupling between the radio frequency coil and other coils adjacent thereto. a

It will be noted also that a small air gap H is left in the radio frequency magnetic circuit so that the control flux will pass mainly through the central portion of the radio frequency core I where its effect is the most pronounced. Windings 6 and I are connected to a suitable source of control current through terminals 8.

Fig. 2 shows another arrangement operating similarly in principle to the arrangement shown in Fig. 1 except that the radio frequency coil I2 and core l3 are elongated and the control winding I4 are wrapped upon the shield l5. An air gap may be left in the radio frequency magnetic circuit if desired but in this case an air gap will not increase the flux through the interior of the radio frequency coil.

Fig. 3 shows the application of a controlled inductance of the type described to the input circuit of a radio receiver for the purpose of preventing overloading of the first tube. The antenna circuit is is normally unbalanced in the presence of weak signals but when the signals are strong enough to produce a predetermined detector input current this predetermined current flowing through the control winding 21 of the antenna coil l8 makes its inductance decrease to a point that will bring the bridge circuit l1, l8 and IS in the antenna system to balance, thus preventing any voltage reaching the first tube 24. Obviously, the detector input can never quite reach this value and hence the input to the first tube 24 can never exceed a predetermined amount. In addition to this type of automatic control of input voltage the rectifled voltage developed across resistor 29 may be also applied to one or more of the grids of the amplifier tubes shown generally at 30 to control the gain thereof in the usual way.

Fig. 4 shows the application of a coil in accordance'with the invention to autcmatic frequency control. The coil is used in the oscillator 30 of a superheterodyne whose frequency is approximately adjusted by the variable condenser 3|. If the frequency is not quite correct a voltage will be developed by the discriminator circuit 32 and thus produce a flux in one direction or the other in the control magneto circuit 33 according to the direction of the misadjustment. A third winding 34 energized to a constant amount by a battery 35 is employed with the result that a flux in one direction produced by the discriminator increases the total flux in the control core 36 while the flux in the opposite direction decreases the total flux. Thus the effective inductance of the oscillator coil 31 is increased or decreased according as the mistuning is in one sense or the other. The action in other respects is identical with that oi known A. F. C. circuits employing a so-called reactance tube for controlling the oscillator frequency. The advantage in the present arrangement lies in the elimination of the extra tube.

I claim:

A compact variable inductance unit comprising a cylindrical radio frequency term-magnetic core, a single radio frequency coil wound coaxially along solely said core, a non-magnetic 10

US297032A 1939-09-29 1939-09-29 Variable inductance arrangement Expired - Lifetime US2302893A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US297032A US2302893A (en) 1939-09-29 1939-09-29 Variable inductance arrangement

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US297032A US2302893A (en) 1939-09-29 1939-09-29 Variable inductance arrangement

Publications (1)

Publication Number Publication Date
US2302893A true US2302893A (en) 1942-11-24

Family

ID=23144578

Family Applications (1)

Application Number Title Priority Date Filing Date
US297032A Expired - Lifetime US2302893A (en) 1939-09-29 1939-09-29 Variable inductance arrangement

Country Status (1)

Country Link
US (1) US2302893A (en)

Cited By (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2463533A (en) * 1944-10-14 1949-03-08 Submarine Signal Co Electrical impedance matching apparatus
US2483314A (en) * 1941-08-16 1949-09-27 Hartford Nat Bank & Trust Co Superheterodyne receiver comprising automatic frequency control
US2499584A (en) * 1945-10-15 1950-03-07 Belmont Radio Corp Signal-seeking tuner
US2503155A (en) * 1948-05-18 1950-04-04 Rca Corp Variable inductance device
US2535154A (en) * 1947-07-08 1950-12-26 Harnischfeger Corp Variable output transformer
US2626318A (en) * 1947-10-04 1953-01-20 Rca Corp Radio-frequency transformer and inductance element therefor
US2652524A (en) * 1943-10-18 1953-09-15 Bailey Meter Co Antihunt electrical measuring system
US2686261A (en) * 1951-01-31 1954-08-10 Products And Licensing Corp Polyphase frequency conversion system
US2811639A (en) * 1953-05-26 1957-10-29 Cgs Lab Inc Signal generating apparatus
US2839684A (en) * 1954-05-06 1958-06-17 Cgs Lab Inc Automatic frequency control
US2849604A (en) * 1957-02-14 1958-08-26 Arf Products Panoramic receiver
US2870334A (en) * 1956-01-13 1959-01-20 George B Crofts Plural section magnetically variable inductor with frequency tracked systems
US2923815A (en) * 1956-12-12 1960-02-02 Cgs Lab Inc Remote tuning of oscillator via duplex conductor
US2927279A (en) * 1954-06-14 1960-03-01 Cgs Lab Inc Variable frequency oscillator system
US2941173A (en) * 1954-09-07 1960-06-14 Cgs Lab Inc Controllable inductor
US2947859A (en) * 1955-08-11 1960-08-02 Motorola Inc Automatic control of coupling between input tuned circuits to vary attenuation and selectivity
US2973431A (en) * 1954-07-22 1961-02-28 Cgs Lab Inc Automobile radio receiver system
US2996682A (en) * 1955-04-01 1961-08-15 Nat Res Dev Variable inductance device
US3037185A (en) * 1951-03-02 1962-05-29 Cgs Lab Inc Sonar apparatus and components
US3074012A (en) * 1954-08-16 1963-01-15 Trak Electronics Company Inc Inductance control apparatus
US3308413A (en) * 1964-08-03 1967-03-07 Magnaflux Corp Saturable reactor having d. c. flux paths of solid ferromagnetic material
US3526727A (en) * 1966-03-24 1970-09-01 Philips Corp Device for automatically eliminating erase oscillator interference in a combined radio and magnetic recorder
US4450588A (en) * 1981-04-15 1984-05-22 Becker Autoradiowerk Gmbh Tuning system for a high frequency receiver utilizing a controllable inductor
US4480178A (en) * 1983-04-04 1984-10-30 At&T Information Systems Tuning arrangement for interfacing credit card-like device to a reader system
DE3502549A1 (en) * 1984-01-30 1985-08-08 Toko Inc Electric controlled, changeable inductor
US5585766A (en) * 1994-10-27 1996-12-17 Applied Materials, Inc. Electrically tuned matching networks using adjustable inductance elements
US20130106500A1 (en) * 2011-10-29 2013-05-02 Intersil Americas Llc. Inductor structure including inductors with negligible magnetic coupling therebetween

Cited By (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2483314A (en) * 1941-08-16 1949-09-27 Hartford Nat Bank & Trust Co Superheterodyne receiver comprising automatic frequency control
US2483889A (en) * 1941-08-16 1949-10-04 Hartford Nat Bank & Trust Co Superheterodyne receiver with automatic frequency control
US2652524A (en) * 1943-10-18 1953-09-15 Bailey Meter Co Antihunt electrical measuring system
US2463533A (en) * 1944-10-14 1949-03-08 Submarine Signal Co Electrical impedance matching apparatus
US2499584A (en) * 1945-10-15 1950-03-07 Belmont Radio Corp Signal-seeking tuner
US2535154A (en) * 1947-07-08 1950-12-26 Harnischfeger Corp Variable output transformer
US2626318A (en) * 1947-10-04 1953-01-20 Rca Corp Radio-frequency transformer and inductance element therefor
US2503155A (en) * 1948-05-18 1950-04-04 Rca Corp Variable inductance device
US2686261A (en) * 1951-01-31 1954-08-10 Products And Licensing Corp Polyphase frequency conversion system
US3037185A (en) * 1951-03-02 1962-05-29 Cgs Lab Inc Sonar apparatus and components
US2811639A (en) * 1953-05-26 1957-10-29 Cgs Lab Inc Signal generating apparatus
US2839684A (en) * 1954-05-06 1958-06-17 Cgs Lab Inc Automatic frequency control
US2927279A (en) * 1954-06-14 1960-03-01 Cgs Lab Inc Variable frequency oscillator system
US2973431A (en) * 1954-07-22 1961-02-28 Cgs Lab Inc Automobile radio receiver system
US3074012A (en) * 1954-08-16 1963-01-15 Trak Electronics Company Inc Inductance control apparatus
US2941173A (en) * 1954-09-07 1960-06-14 Cgs Lab Inc Controllable inductor
US2996682A (en) * 1955-04-01 1961-08-15 Nat Res Dev Variable inductance device
US2947859A (en) * 1955-08-11 1960-08-02 Motorola Inc Automatic control of coupling between input tuned circuits to vary attenuation and selectivity
US2870334A (en) * 1956-01-13 1959-01-20 George B Crofts Plural section magnetically variable inductor with frequency tracked systems
US2923815A (en) * 1956-12-12 1960-02-02 Cgs Lab Inc Remote tuning of oscillator via duplex conductor
US2849604A (en) * 1957-02-14 1958-08-26 Arf Products Panoramic receiver
US3308413A (en) * 1964-08-03 1967-03-07 Magnaflux Corp Saturable reactor having d. c. flux paths of solid ferromagnetic material
US3526727A (en) * 1966-03-24 1970-09-01 Philips Corp Device for automatically eliminating erase oscillator interference in a combined radio and magnetic recorder
US4450588A (en) * 1981-04-15 1984-05-22 Becker Autoradiowerk Gmbh Tuning system for a high frequency receiver utilizing a controllable inductor
US4480178A (en) * 1983-04-04 1984-10-30 At&T Information Systems Tuning arrangement for interfacing credit card-like device to a reader system
DE3502549A1 (en) * 1984-01-30 1985-08-08 Toko Inc Electric controlled, changeable inductor
US5585766A (en) * 1994-10-27 1996-12-17 Applied Materials, Inc. Electrically tuned matching networks using adjustable inductance elements
US20130106500A1 (en) * 2011-10-29 2013-05-02 Intersil Americas Llc. Inductor structure including inductors with negligible magnetic coupling therebetween
US10529475B2 (en) * 2011-10-29 2020-01-07 Intersil Americas LLC Inductor structure including inductors with negligible magnetic coupling therebetween

Similar Documents

Publication Publication Date Title
US2211750A (en) Wireless telegraph system
US2774866A (en) Automatic gain and band width control for transistor circuits
US2438359A (en) Television receiver circuits and apparatus
US3961292A (en) Radio frequency transformer
US2338134A (en) Variable tuning system
US2098331A (en) Automatic station selector for radio receivers
US2581202A (en) Multistage variable-saturation tuning system and apparatus
US2236195A (en) Automatic cathode voltage adjusting device
US4099116A (en) Metal detector with phase related circuit selective discrimination
US4395714A (en) Antenna array system usable for AM/FM receiver
US2375309A (en) High-frequency transformer
US2406045A (en) Inductance device
US2223990A (en) Cathode ray tube apparatus
US2137435A (en) Volume control device
US2860313A (en) Inductive tuning device
US2286378A (en) Frequency modulated wave detector
GB661053A (en) Improvements in and relating to saturable reactor magnetic amplifiers
US2426580A (en) Radio receiver
US2555906A (en) Tunable amplifier having a predetermined band-pass characteristic throughout its range
US2340749A (en) Variable permeability tuning system
US2302798A (en) Thermionic valve amplifier
US2325279A (en) Signal collecting system
US2122283A (en) Frequency converter
USRE23311E (en) Method of and means for neutraliz
GB559967A (en) Amplitude-and frequency-modulation radio receivers