US2417296A - Low-frequency amplifier circuits - Google Patents

Low-frequency amplifier circuits Download PDF

Info

Publication number
US2417296A
US2417296A US480189A US48018943A US2417296A US 2417296 A US2417296 A US 2417296A US 480189 A US480189 A US 480189A US 48018943 A US48018943 A US 48018943A US 2417296 A US2417296 A US 2417296A
Authority
US
United States
Prior art keywords
transformer
anode
choke coil
circuit
amplifier
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
US480189A
Inventor
Dikstaal Simon Anne
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.)
Hartford National Bank and Trust Co
Original Assignee
Hartford National Bank and Trust Co
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 Hartford National Bank and Trust Co filed Critical Hartford National Bank and Trust Co
Application granted granted Critical
Publication of US2417296A publication Critical patent/US2417296A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R3/00—Circuits for transducers, loudspeakers or microphones
    • H04R3/04—Circuits for transducers, loudspeakers or microphones for correcting frequency response
    • H04R3/08—Circuits for transducers, loudspeakers or microphones for correcting frequency response of electromagnetic transducers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/02—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements with tubes only
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
    • H03F3/22—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with tubes only

Definitions

  • This invention relates to a low-frequency amplifier circuit in which the oscillations to be amplified are fed to the grid circuit of an amplifier valve whose anode circuit includes the series connection formed by a condenser and the primary winding of a transformer from whose secondary winding the amplified oscillations are derived and whose anode direct voltage is supplied to the anode through a choke coil.
  • Such circuit is known to offer the advantage that the anode direct current of the amplifier valve does not pass through the primary winding of the transformer and that substantially higher values of the inductances of the windings can thus be achieved, as is desirable with a view of obtaining uniform amplification, even of the low frequencies.
  • the circuit has, however, the disadvantage that two iron cores (which are to be sufficiently free from iron losses and for this reason are to be formed from thin sheets of magnetic material), are needed, one for the choke coil and another for the transformer. This involves a. higher cost for assembling the iron cores.
  • the choke coil and the transformer have to be mounted each individually and this further adds to the cost of the circuit. Since in practice, and more particularly in mass production, the cost of production should be kept as low as possible, the circuit described not well adapted for practical use.
  • the choke coil winding and the two transformer windings are arranged respectively on the outer limbs of an iron core of the shell-type.
  • This saving is achieved due to the fact that in a device according to the invention only one core need be stacked for the choke coil and the transformer jointly, any further treatment, such as impregnation or the like, needs only to be carried out for a sin le component member instead of two and. finally only one component member need be mounted in the apparatus.
  • FIG. 1 A diagrammaticalliy i1 1.
  • Figs. 2 and 3 show respectively front and end views of the iron core utilized in Fig. 1.
  • the amplifier circuit shown in. Fig. 1 includes amp Tier valve i which has the oscillations to he amplifie e. fed to it between the control grid 2 and the cathode 3.
  • tions occurring in the anode circuit of the valve I are fed to the small speech coil 4 of a dynamic loudspeaker 5.
  • a condenser 8 which prevents the anode direct current of the valve 5 from flowing through the primary winding of the transformer.
  • the anode voltage is supplied to the anode l of the amplifier valve 2 with the interposition of a choke coil 9.
  • the speech coil t is connected to the secondary winding of the transformer 8.
  • the windings of the transformer 6 and of the choke coil 9 are arranged on the outer limbs l0 and I!
  • an iron core E2 of the shell type which is formed from E-shaped and I-shaped transformer laminations of the kind use for shelltype transformers, shown respectively at it and it in Figs. 2 and 3. Due to the larger iron section of the middle limb 13 the magnetic lines of force of the choke coil Will not bring about saturation in the magnetic circuit of the transformer so that the primary inductance of the transformer is not affected by the anode direct current of the valve i which passes through the choke coil.
  • the condenser 8 is preferably so dimensioned that resonance occurs for any frequency in the lower-most part of the audible spectrum.
  • the E- and I-shaped laminations may first be stacked at the correct level, the previously finished coils are then pushed each over one of the outermost limbs and after that the aggregate of choke coil and transformer can further be finished as a Whole, be impregnated and be subsequently housed in the set concerned.
  • a low-frequency amplifier circuit in which the oscillations to be amplified are fed to the grid circuit of an amplifier valve and in which the anode circuit of the said valve includes the series combination of a condenser and the primary winding of a transformer from whose secondary winding the amplified oscillations are derived and in which the anode direct voltage is supplied to the anode of the valve through a choke ccii, wherein the choke coil winding and the two windings of the transformer are arranged respectively on the two outer limbs of an iron core of the shell type which is formed from E-shaped and I-shaped laminations, the central limb being so dimensioned with respect to the outer limbs that the magnetic lines of force due to the choke coil winding are ineiiective to bring about saturation in the magnetic circuit of the transformer, 0 that the primary inductance of the transformer is not affected by the anode direct current of the valve which passes through the choke coil winding.
  • a low-frequency amplifier circuit in which the oscillations to be amplified are fed to the grid circuit of an amplifier valve and in which the anode circuit of the said valve includes the series combination of a condenser 'and'a transformer from which the amplified oscillations are derived and in which the anode direct voltagev is supplied to the anode of the valve through a choke coil, wherein the choke coil and the transformer are arranged respectively on the two outer limbs of an iron core of the shell type which is formed from E-shaped and I-shaped laminations, the centrallimbbeing so dimensioned with respect to the outer limbs that the magnetic lines of force due to the choke coil winding are ineffective'to bring about saturation in the magnetic circuit of the transformer, so that the primary inductance of the transformer is not affected by the anode .direct current of the valve which passes through the choke coil winding.
  • An audio frequency coupling system for coupling the output or anode of a vacuum tube amplifier to a utilization device, comprising a closed.
  • iron core having a central limb and two outer limbs, a choke coil through which direct voltage is supplied to the anode of the amplifier Wound around one of the outer limbs, a transformer having its primary winding connected to the amplifier anode and its secondary. winding connected to the utilization device, said transformer windings being wound around the second outer limb, the central limb being so dimensioned with respect to the outer limbs that the magnetic lines of force due to the choke coil winding are ini 4 effective to bring about saturation in the magnetic circuit of the transformer, so that the primary inductance of the transformer is not affected by the anode direct current of said amplifier which passes through the choke coil windmg.
  • An audio frequency coupling system for coupling the anode circuit of a vacuum tube amplifier to the voice coil of an acoustical reproducer, comprising a closed iron core having a central limb and two outer limbs, a choke coil through which direct voltage is supplied to the anode of said amplifier wound around one of the outer limbs, a transformer having its primary winding connected in series with a capacitor to the anode of said amplifier and its secondary winding connected to the voice coil of said reproducer, said transformer windings being wound around the second outer limb, and the center limb being so dimensioned with respect to the outer limbs that the magnetic lines of force due to the choke coil windings are ineffective to bring about saturation in the magnetic circuit of the transformer so that the primary inductance of the transformer is not affected by the anode direct current of said amplifier which passes through the choke coil winding, and said capacitor being of such value that with the inductances present in the system resonance occurs at any frequency in the lowermost part of the audible spectrum.

Description

March 11, 1947. s, A, DlKSTAAL 2,417296 LOW-FREQUENCY AMPLIFIER G IRCUITS Filed March 23, 1943 ATTORNEY Patented Mar. 11, 1947 2,417,296 LOW-FREQUENCY AMPLIFIER CIRCUITS Simon Anne Dikstaal, Eindhoven, Netherlands, assignor to Hartford National Bank and Trust Company, Hartford, Conn., as trustee Application March 23, 1943,
In the Netherlands April 9,
Ciaims. 1
This invention relates to a low-frequency amplifier circuit in which the oscillations to be amplified are fed to the grid circuit of an amplifier valve whose anode circuit includes the series connection formed by a condenser and the primary winding of a transformer from whose secondary winding the amplified oscillations are derived and whose anode direct voltage is supplied to the anode through a choke coil.
Such circuit is known to offer the advantage that the anode direct current of the amplifier valve does not pass through the primary winding of the transformer and that substantially higher values of the inductances of the windings can thus be achieved, as is desirable with a view of obtaining uniform amplification, even of the low frequencies.
In contradistinction to this advantage, the circuit has, however, the disadvantage that two iron cores (which are to be sufficiently free from iron losses and for this reason are to be formed from thin sheets of magnetic material), are needed, one for the choke coil and another for the transformer. This involves a. higher cost for assembling the iron cores. In addition, the choke coil and the transformer have to be mounted each individually and this further adds to the cost of the circuit. Since in practice, and more particularly in mass production, the cost of production should be kept as low as possible, the circuit described not well adapted for practical use.
According to the invention, a considerable saving in cost is achieved in the circuit described in that the choke coil winding and the two transformer windings are arranged respectively on the outer limbs of an iron core of the shell-type. This saving is achieved due to the fact that in a device according to the invention only one core need be stacked for the choke coil and the transformer jointly, any further treatment, such as impregnation or the like, needs only to be carried out for a sin le component member instead of two and. finally only one component member need be mounted in the apparatus.
In order that the invention may be clearly understood and readily carried into effect one form of construction of an amplifier circuit according to the invention is shown diagrammaticalliy i1 1. Figs. 2 and 3 show respectively front and end views of the iron core utilized in Fig. 1.
The amplifier circuit shown in. Fig. 1 includes amp Tier valve i which has the oscillations to he amplifie e. fed to it between the control grid 2 and the cathode 3. The amplified oscilla- Serial No. 480,189
tions occurring in the anode circuit of the valve I are fed to the small speech coil 4 of a dynamic loudspeaker 5. In series with the primary windillg of the output transformer 5 is connected a condenser 8 which prevents the anode direct current of the valve 5 from flowing through the primary winding of the transformer. The anode voltage is supplied to the anode l of the amplifier valve 2 with the interposition of a choke coil 9. The speech coil t is connected to the secondary winding of the transformer 8. The windings of the transformer 6 and of the choke coil 9 are arranged on the outer limbs l0 and I! respectively of an iron core E2 of the shell type which is formed from E-shaped and I-shaped transformer laminations of the kind use for shelltype transformers, shown respectively at it and it in Figs. 2 and 3. Due to the larger iron section of the middle limb 13 the magnetic lines of force of the choke coil Will not bring about saturation in the magnetic circuit of the transformer so that the primary inductance of the transformer is not affected by the anode direct current of the valve i which passes through the choke coil.
The condenser 8 is preferably so dimensioned that resonance occurs for any frequency in the lower-most part of the audible spectrum.
In the construction of the choke coil transformer combination the E- and I-shaped laminations may first be stacked at the correct level, the previously finished coils are then pushed each over one of the outermost limbs and after that the aggregate of choke coil and transformer can further be finished as a Whole, be impregnated and be subsequently housed in the set concerned.
What I claim is:
l. A low-frequency amplifier circuit in which the oscillations to be amplified are fed to the grid circuit of an amplifier valve and in which the anode circuit of the said valve includes the series combination of a condenser and the primary winding of a transformer from whose secondary winding the amplified oscillations are derived and in which the anode direct voltage is supplied to the anode of the valve through a choke ccii, wherein the choke coil winding and the two windings of the transformer are arranged respectively on the two outer limbs of an iron core of the shell type which is formed from E-shaped and I-shaped laminations, the central limb being so dimensioned with respect to the outer limbs that the magnetic lines of force due to the choke coil winding are ineiiective to bring about saturation in the magnetic circuit of the transformer, 0 that the primary inductance of the transformer is not affected by the anode direct current of the valve which passes through the choke coil winding.
2. An amplifier circuit as claimed in claim 1, wherein the condenser is so dimensioned that with the inductances present in the device resonance occurs'at any frequency in the lowermost part of the audible spectrum.
3. A low-frequency amplifier circuit in which the oscillations to be amplified are fed to the grid circuit of an amplifier valve and in which the anode circuit of the said valve includes the series combination of a condenser 'and'a transformer from which the amplified oscillations are derived and in which the anode direct voltagev is supplied to the anode of the valve through a choke coil, wherein the choke coil and the transformer are arranged respectively on the two outer limbs of an iron core of the shell type which is formed from E-shaped and I-shaped laminations, the centrallimbbeing so dimensioned with respect to the outer limbs that the magnetic lines of force due to the choke coil winding are ineffective'to bring about saturation in the magnetic circuit of the transformer, so that the primary inductance of the transformer is not affected by the anode .direct current of the valve which passes through the choke coil winding.
4. An audio frequency coupling system for coupling the output or anode of a vacuum tube amplifier to a utilization device, comprising a closed.
iron core having a central limb and two outer limbs, a choke coil through which direct voltage is supplied to the anode of the amplifier Wound around one of the outer limbs, a transformer having its primary winding connected to the amplifier anode and its secondary. winding connected to the utilization device, said transformer windings being wound around the second outer limb, the central limb being so dimensioned with respect to the outer limbs that the magnetic lines of force due to the choke coil winding are ini 4 effective to bring about saturation in the magnetic circuit of the transformer, so that the primary inductance of the transformer is not affected by the anode direct current of said amplifier which passes through the choke coil windmg.
5. An audio frequency coupling system for coupling the anode circuit of a vacuum tube amplifier to the voice coil of an acoustical reproducer, comprising a closed iron core having a central limb and two outer limbs, a choke coil through which direct voltage is supplied to the anode of said amplifier wound around one of the outer limbs, a transformer having its primary winding connected in series with a capacitor to the anode of said amplifier and its secondary winding connected to the voice coil of said reproducer, said transformer windings being wound around the second outer limb, and the center limb being so dimensioned with respect to the outer limbs that the magnetic lines of force due to the choke coil windings are ineffective to bring about saturation in the magnetic circuit of the transformer so that the primary inductance of the transformer is not affected by the anode direct current of said amplifier which passes through the choke coil winding, and said capacitor being of such value that with the inductances present in the system resonance occurs at any frequency in the lowermost part of the audible spectrum.
SIMON ANNE DIKSTAAL.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 1,808,726 Donle June 2, 1931 1,908,934 Trube May 16, 1933 1,429,634 Robinson Sept. 19, 1922 1,881,515 Grimley Oct. 11, 1932 1,815,023 Donle July 14-, 1931.
US480189A 1941-04-09 1943-03-23 Low-frequency amplifier circuits Expired - Lifetime US2417296A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL2417296X 1941-04-09

Publications (1)

Publication Number Publication Date
US2417296A true US2417296A (en) 1947-03-11

Family

ID=19874181

Family Applications (1)

Application Number Title Priority Date Filing Date
US480189A Expired - Lifetime US2417296A (en) 1941-04-09 1943-03-23 Low-frequency amplifier circuits

Country Status (2)

Country Link
US (1) US2417296A (en)
FR (1) FR881084A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2452563A (en) * 1944-01-15 1948-11-02 Standard Telephones Cables Ltd Circuits for repeating square shaped wave forms
US2515683A (en) * 1946-12-20 1950-07-18 Jose W Acosta Circuit coupling device for highfrequency therapeutic apparatus

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1429634A (en) * 1919-04-01 1922-09-19 Robinson Charles Telephonic repeater
US1808726A (en) * 1928-05-09 1931-06-02 Radio Inventions Inc Audio frequency coupling
US1815023A (en) * 1927-02-19 1931-07-14 Radio Inventions Inc Amplifier coupling
US1881515A (en) * 1926-08-31 1932-10-11 Bell Telephone Labor Inc Transmission circuit
US1908934A (en) * 1930-05-14 1933-05-16 Hazeltine Corp Electric coupling system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1429634A (en) * 1919-04-01 1922-09-19 Robinson Charles Telephonic repeater
US1881515A (en) * 1926-08-31 1932-10-11 Bell Telephone Labor Inc Transmission circuit
US1815023A (en) * 1927-02-19 1931-07-14 Radio Inventions Inc Amplifier coupling
US1808726A (en) * 1928-05-09 1931-06-02 Radio Inventions Inc Audio frequency coupling
US1908934A (en) * 1930-05-14 1933-05-16 Hazeltine Corp Electric coupling system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2452563A (en) * 1944-01-15 1948-11-02 Standard Telephones Cables Ltd Circuits for repeating square shaped wave forms
US2515683A (en) * 1946-12-20 1950-07-18 Jose W Acosta Circuit coupling device for highfrequency therapeutic apparatus

Also Published As

Publication number Publication date
FR881084A (en) 1943-04-14

Similar Documents

Publication Publication Date Title
US2417296A (en) Low-frequency amplifier circuits
US1732937A (en) Transformer and coil system
GB194424A (en) Improvements in electro-magnetic apparatus for recording sound
US2896180A (en) Saturable transformer
US1505085A (en) Radio receiving apparatus
US2096801A (en) Power transformer
US4032836A (en) Transformer circuit
GB563517A (en) Improvements in electric transformers, chokes and inductances
GB2120862A (en) Transformer for audio amplification circuit
US1550889A (en) Induction device and magnetic circuits for the same
US2120973A (en) Electrical coil
US1624536A (en) Inductance device
US2707773A (en) Audio frequency transformer
GB463348A (en) Improvements in and relating to magnetic cores
US1728879A (en) Amplifying system
GB322814A (en) Improvements in and relating to thermionic amplifiers
US1688265A (en) Radiocircuits
US2048528A (en) Low frequency amplifier
US2189161A (en) Sound reproducing apparatus and a wiring circuit therefor
SU42600A1 (en) Multiwinding Transformer
GB455190A (en) Method of regulating radio sets and the like
GB1113263A (en) A high voltage transformer or inductance
US1588162A (en) Transformer
GB200254A (en) Means for reducing the distortion in a telephone or like repeating system
US2544195A (en) High-frequency iron-cored coil