US2477074A - Wide band amplifier coupling circuits - Google Patents

Wide band amplifier coupling circuits Download PDF

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US2477074A
US2477074A US66741A US6674148A US2477074A US 2477074 A US2477074 A US 2477074A US 66741 A US66741 A US 66741A US 6674148 A US6674148 A US 6674148A US 2477074 A US2477074 A US 2477074A
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windings
winding
cathode
anode
transformer
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Frank H Mcintosh
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Priority to NL737305804A priority Critical patent/NL150547B/xx
Priority to NL79816D priority patent/NL79816C/xx
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Priority to FR1002802D priority patent/FR1002802A/fr
Priority to CH296850D priority patent/CH296850A/fr
Priority to DEI288D priority patent/DE842502C/de
Priority to GB32863/49A priority patent/GB677921A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F19/00—Fixed transformers or mutual inductances of the signal type
    • H01F19/04—Transformers or mutual inductances suitable for handling frequencies considerably beyond the audio range
    • H01F19/06—Broad-band transformers, e.g. suitable for handling frequencies well down into the audio range
    • 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
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/26—Push-pull amplifiers; Phase-splitters therefor
    • H03F3/28—Push-pull amplifiers; Phase-splitters therefor with tubes only
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/50—Amplifiers in which input is applied to, or output is derived from, an impedance common to input and output circuits of the amplifying element, e.g. cathode follower
    • H03F3/52—Amplifiers in which input is applied to, or output is derived from, an impedance common to input and output circuits of the amplifying element, e.g. cathode follower with tubes only

Definitions

  • the present invention relates generally to im- 2 proved audio and video frequency amplifiers, and to transformers utilizable therein, and more particularly to improved class B audio and video frequency electronic amplifiers which introduce extremely slight distortion over a wide band of frequencies, by utilizing output transformers of novel design, connected in novel relation to the electronic tubes of the amplifier.
  • the class B amplifier is a push-pull amplifier in which the tubes are biased approximately to cut-off.
  • One of the tubes in the normal system, amplifies the positive half cycles of the signal voltage while the other amplifies the negative half cycles, the output transformer combining the outputs of the two tubes, to reconstruct a replica of the signal voltage.
  • the frequency limits of the conventional audio or video amplifier depend largely upon the design of the output transformer, loss in amplification at low frequencies resulting from the low incremental inductance of the transformer primary, and falling off at high frequencies resulting from leakage inductance and the various distributed capacities of the transformer.
  • the incremental primary inductance of the transformer must be high relative to the plate resistances of the tubes used.
  • the primary winding of the transformer then, should have a large number of turns.
  • the resonant frequency of the leakage inductance and secondary capacitance must be beyond the highest frequency desired to be amplified, so that low leakage inductance and shunt capacity is essential, if the frequency response of the transformer is to be extended.
  • the above requirements are mutually conflicting, in various respects.
  • the size of the core of a transformer i. e., the total iron utilized, is limited by considerations of cost, space and weight requirements. This in turn fixes the total number of turns allotted to the primary and secondary windings. Decreasing core size and increasing total turns on the primary winding to retain high primary incremental inductance increases leakage inductance and shunt capacity, which in turn, reduces resonant frequency, and hence the high frequency response of the transformer. In practice, leakage inductance is decreased by interleaving primary and secondary windings, but this increases distributed capacity and so tends to neutralize the benefits obtained.
  • high permeability cores must be used, to increase primary winding 9 Claims. (Cl. 179-171) impedance. Such cores are adversely affected, in respect to the incremental inductance, by D. C. magnetization. Hence the latter must be avoided.
  • the effect of leakage inductance on class B push-pull amplifiers has been considered in the literature, and attention is directed particularly to an article by A. Pen-Tung Sah, in Proceedings of the I. R. E. for November, 1936.
  • Sah points out particularly the deleterious effects of leakage inductance between primary windings of the output transformer of such an amplifier, first, in causing a decreased output, as frequency increases, and second, in introducing finite time constants into the circuit, thus causing transients which distort the output wave as one of the tubes changes from a conducting condition to a blocking condition, and vice-versa.
  • the latter effect is the basis of great distortion at the higher audio frequenmes.
  • an object of the invention to provide a push-pull transformer, having greater coupling between the secondary winding and the primary windings than is available in known designs, without increasing detrimental capacity effects, thereby to improve the frequency response and to enlarge the band width of such transformers when employed in amplifiers.
  • the equivalent shunt capacity across the primary windings due to the capacity between windings, which together with leakage reactance and the capacity of the secondary winding determine falling off of response at the higher audio frequencies and the high frequency cut-off point of the amplifier, may be similarly reduced, and the windings may be so related to the electronic tubes of the amplifier that but a single anode power supply is required, and that in certain of the embodiments conventional input circuits may be employed.
  • the conventional mode of reducing leakage inductance consists of sectionalizing primary and secondary windings and interleaving or interspersing these. This type of construction is expensive, and while it succeeds in reducing leakage inductance, results in increased capacities.
  • the ,total capacity of the transformer windings may be reduced by avoiding the necessity for interleaving or pi-winding, in accordance with the present invention, in order to reduce leakage inductance.
  • the transformer of the present invention may be arranged more compactly than previously known transformers of the same performance, resulting in reduction of iron requirements, and in a, simplified, more economically fabricated core and winding structure.
  • the primary Windings of the transformer are connected in series between the plates of the electronic tubes of the amplifier. Accordingly, the primary windings being closely coupled, the total impedance of the primary windings is approximately four times the impedance of a single primary winding.
  • the primary windings of the output transformer are not connected in series with each other between the amplifier tubes, but are connected effectively in parallel. Thereby a reduction in anode terminal to anode terminal impedance of (4), approximately, may be attained.
  • each coil by reason of its bifilar relation to another coil, is for the same length of wire and length of coil of double the number of layers, resulting in a further decrease of shunt capacity.
  • Reduction of anode to anode impedance of the windings is, therefore, reflected in a corresponding decrease in anode to anode distributed capacity across the windings, and therefore in a radical extension upwards of the cut oif frequency of the amplifier, at its high end.
  • more turns may be employed in the primary windings, and the resultant increase of shunt capacity, due to increase in the number of turns, can be tolerated.
  • Audio amplifiers constructed in accordance with the present invention, and tested for distortion, have shown less than /a% distortion over the band 20 to 20,000 cycles, the conversion efficiency-of the amplifier tubes remaining above 50% over the band, with an essentially flat response over the band of 20 to 200,000 cycles.
  • transformers constructed in accordance with the present invention inherently cost less to build than do transformers of the highest quality fabricated in accordance with prior art principles, and require less space and weigh less than the latter.
  • Figure 1 is a schematic circuit diagram of an embodiment of the invention wherein is employed a pair of bifilarly wound primary coils in an output transformer, one of the coils being connected in the cathode circuit of a vacuum tube of a pushull amplifier, and the remaining coil connected in the anode circuit of the amplifier;
  • FIG. 2 is a schematic circuit diagram of a further embodiment of the invention wherein is utilized a transformer having two bifilarly wound primary coils, each comprising two windings, each bifilarly wound coil having one of its windings connected in the cathode circuit and the other in the anode circuit of one of the vacuum tubes of the amplifier;
  • FIG 3 is a schematic circuit diagram illustratin a modification of the system illustrated in Figure 2 of the drawings, wherein the push pull amplifier utilizes vacuum tubes having screen I grids, each screen grid being maintained at a constant diilerence of potential with respect to its associated cathode during operation of the amplifier;
  • Figure 4 is a schematic circuit diagram of a modification oi the system of Figure 2, wherein controllable degeneration is provided in the amplifier;
  • Figure is a schematic circuit diagram of a variation of the system of Figure 1 of the drawings, arranged for balanced operation;
  • Figure 6 is a schematic circuit diagram of a variation of the embodiment illustrated in Figure 2 of the drawing, wherein the output trans- -former is an auto-transformer;
  • Figure 7 is a view, showing a transformer having bifllarly wound primary windings for use in, .push-pull amplifiers arranged in accordance with the invention.
  • FIGs 8, 9 represent variations of the unity coupled transformer of Figure 7.
  • the amplifier of Figure 1 is illustrated as employing a pair of triodes i, 2 as amplifying electronic devices, the triodes i and 2 being provided respectively with grid leaks 3 and s, which are connected between the control electrodes 5 and 6 of the triodes. i and 2, respectively, the midpoint of the grid leak resistors 3 and 4 being grounded via a. bias source 1.
  • Driving potential is applied to the control electrodes 5 and 6 from sources conventionally illustrated as generators 8, 9, which may be presumed to provide potentials of opposite phases with respect to ground, and of suitable relative magnitudes, the potentials provided by the sources 8, 9 being applied to the control electrodes 5, 6 via coupling condensers l0 and H respectively, the resistors I2 and i 3 representing the internal resistances of sources 8 and 9, respectively.
  • the bias established by the bias source I may be such as to cause operation of the triodes i and 2 to be either as class A, class AB or class B amplifiers, the significance of the classification being well un derstood in the art, and defined by the Institute of Radio Engineers in its ofilcial definitions. While the circuits and structures oi! the present application have wide utility in amplifiers operating in accordance with any one oi the above mentioned classifications, the invention has primary application to class B amplifiers, and will be described accordingly as utilized in amplifiers of this class, without intending thereby to limit the scope of the invention.
  • the bias source 1 will be established to have a value such as to cut on" the plate current of the triodes i and 2, in the absence of signal voltage applied to the grids thereof.
  • the input circuits of the triodes l and 2 will, accordingly, be seen to be completely conventional and to form essentially no part of the present invention.
  • a source of anode voltage is provided, conventionally illustrated as a battery to simplify the drawings.
  • the negative terminal of source It is grounded via the lead l5, and the positive terminal of source is is connected directly via the lead Hi to the anode ll of the triode I, the primary winding l8 of output transforcer T being connected in the cathode lead or the triode l, intermediate the cathode ll thereoi and the negative terminal or the potential source II.
  • the cathode 22 of the triode 2 is connected directly to ground and a further primary winding 2
  • are wound in biillar manner, or equivalently, as indicated in the schematic circuit diagram, the wires forming one of the windings being immediately adjacent the wires forming the other of the windings so that substantially zero leakage inductance exists as between the windings l8 and 2
  • triode 2 is cut oif, and the triode l conducting, for example, the winding it induces in the winding 2! a voltage congruent with its own voltage, and in the same sense in the two windings, the voltage in winding 2 l, however, being incapable of causing current flow in triode 2 because the input voltage applied to grid 6 is now negative in phase and of suificient amplitude with respect to the voltage applied to the anode 22 of triode 2 by winding 2i, to prevent such current flow. Precisely the same argument may be presented when triode 2 is conducting and triode I cut oil.
  • terminals 28 and 29 of the primary windings l8 and 2i are directly connected together via the potential source ll, which may be assumed to have zero impedance, and the total number of turns contained in the windings it cathode lead of the triode 2.
  • a condenser C may, if desired, be connected directly from cathode is to anode 22 without al- 'tering the operation of the system essentially, but to assure the equipotential relation between adjacent turns, particularly at the higher frequencies, where some leakage reactance might conceivably be present due to imperfections of the winding spacings.
  • the negative terminal of the anode supply I4 is again grounded, the positive terminal of one winding 30 being connected via the lead 3i to the anode 22 of the triode 2, and a second winding 33, in series with winding 36, being connected via the lead 34 to the anode ii of the triode 1. Accordingly, the windings 3d and 33 are connected in push-pull relation to the triodes I and 2, and pass currents in alternation if the triodes I and 2 are biased for class-,B operation.
  • a further winding, 35 is connected in the cathode lead of the triode l, and a winding 35, in series with winding 35, similarly connected in the Accordingly, current flow in the winding 35 takes place in phase with current flow in the winding 33, these current flows being additive in respect to flux production in the core of transformer T.
  • current flow in the cathode winding 36 is in phase with current flow in the winding 30, and flux production responsive to the current flow in the windings 30 and 36 is cophasal in the core of the transformer T.
  • th magnitudes of the currents flowing in the windings 33 and 35 are identical and the magnitudes of the currents flowing in the windings 30 and 36 are identical,
  • windings 30, 33, 33 and 33 are provided with the same number of turns.
  • the terminals 31 and 38 of the windings 33 and 38 are connected together over the extremely low impedance provided by the potential source I4 and. accordingly, may be assumed to be at the same A. C. potential.
  • windings 3d and 35 are wound in bifilar or equivalent fashion, as are the windings 33 and 33, so that substantially no leakage inductance exists among the winding pairs 33, 33 and 35, 36.
  • both the amount and the character of the potential difference between the cathode and the screen grid of a pentode, or a tetrode are parameters which determine in large part the power conversion eficiency oi the tube. Since the cathode potentials of cathode loaded pentode or tetrode tubes vary with respect to ground, it follows that if the screen potentials are fixed with respect to ground the cathode to screen potentials will vary, and, in general, the power conversion efilciency of the tubes will be found to be reduced.
  • the size of the screen grid dropping resistance varies in inverse proportion to the potential difference between the screen grid and the cathode, as the resistance is varied.
  • the minimum size of the screen grid dropping resistance is limited by the amount of loading imposed on the output circuit due to this resistance, so that an ideal solution cannot be realized, and maximum power conversion from pentode and tetrode tubes in cathode loaded circuits likewise cannot be obtained.
  • the circuit illustrated in Figure 3 of the drawing provides a solution to the problem of attaining maximum power conversion from pentode and tetrode tubes in cathode loaded push-pull amplifier circuits, arranged in accordance with the present invention, the solution consisting in connecting the screen grid 42 of one pentode 40 directly to the anode 43 of the other pentode, and the screen grid 44 of the other pentode 4i directly to the anode 45 of the first pentode 40.
  • the connection of the screen grid 42 to the anode 43 implies connection of the screen grid 42 to the terminal 45 of the output transformer winding 30, which, as has been explained, in connection with the embodiment of my invention illustrated in Figure 2 of the drawings, is maintained at the same A. C. potential as is the point 31 of the winding 35.
  • the terminal 31 is always at the cathode potential of the pentode 40, likewise the terminal 45 of the winding 30 is maintained at the same A. C. potential as is the cathode of the pentode 40, the D. C. potential exist 'ing between the two points being, however, that provided by the potential source l4. Accordingly, as the cathode of the pentode l varies in potential, due to the presence in the cathode circuit of the current carrying winding 36, the potential of the screen grid 52 varies in precisely similar manner. The difference in potential is thus maintained constant, thereby maintaining maximum power conversion from the pentode.
  • controllable degenerative feed-back is derived by connecting across the primary windings 35 and 35, which are connected in the cathode leads of the tricdes I and 2, a resistor 5D, the latter then having developed across itself a voltage which is a replica of the output voltage available at the output of the transformer T.
  • a pair of variable taps 5i and 52 are provided, taps 5i and 52 being located generally at points equidistantly located with respect to cathodes 2B and I9, respectively. Accordingly, by varying the positions of the taps 5i and 52 the total feed-back voltage to each of triodes I and 2 may be varied.
  • the voltage deriving from the tap 5! is applied to control electrode 8, via a coupling condenser 53, which is connected to one terminal of the secondary winding 55 of an input transformer S, which is supplied with exciting voltage via a primary winding 57 excited from the source of signal voltage A in conventional fashion.
  • the remaining terminal of sec ondary winding 56 is connected to the control electrode 6 of the triode 2.
  • the tap 52 introduces a degenerative voltage into the grid of the triode I via a coupling condenser 531: which is connected in series with one terminal of the secondary winding 58 of the transformer S, the other terminal of winding 58 being connected to the control electrode 5 of the triode I.
  • Grid leaks for triodes I and 2 are provided by resistors 59 and 54, respectively connected in serieswith bias source 55.
  • a primary winding I8 of a transformer T is connectedin series with a cathode circuit of a first triode I and a further primary winding 2
  • the tube I is cathode loaded by means of the primary winding I8 of transformer T.
  • Input signal from the secondary 60 of an input transformer S is applied between the control electrode 5 of the tube I and the terminal 51 of winding I8 via leads 65 and 65.
  • the tube 2 is driven in a difierent manner in Figure 5 than is the triode 2 in Figure 1, the tube 2 being effectively cathode loaded in the system of Figure 5.
  • is connected in the anode circuit of the tube 2, in a similar manner to the connecions previously described in conjunction with Figure l of the drawings.
  • a further signal is applied in opposite phase to the first mentioned input signal via a winding 52 connected between the anode 22 of the tube 2 and the controle electrode 6 of the tube 2 via the usual block ing condenser C.
  • the input circuit of tube l sees two alternative voltages, one originating in the primar winding 63 and which is inductively transferred to the secondary winding 60, the second constituting a degenerative feed-back voltage deriving from the primary winding E8 of the output transformer T by virtue of the connection of the terminal M of the secondary winding 50 via the lead 65, 66 to the negative terminal 6'5 of the primary winding i 8.
  • the input circuit of tube 2 sees two alternating voltages, one originating in the primary winding 53, which is inductively transferred to the secondary winding 62, the second constituting a degenerative feed-back voltage, deriving from the primary winding 2
  • the input voltage for tube 2 consists of the voltages of windings 2i and 62 in series.
  • a screen grid 61 may be connected directly to anode 22 of tube 2, and will be maintained at a constant potential with respect to cathode l9 of tube l equal to the voltage of source H, because the same A.-C. voltages exist at all times on anode 22 and on cathode 59.
  • a capacitor, C may be connected from cathode H to anode 22.
  • a screen grid 68 provided in tube 2 may be connected directly to the positive terminal of source I 4, and will'be maintained at an A.-C. voltage difference from the potential of cathode 20 equal to the voltage of source ll, since no impedance exists between screen grid 68 and cathode 20.
  • tubes land 2 in Figure 5 of the drawings may then be triodes
  • tetrodes tetrodes, pentodes, beam power tubes, or the like, as desired, and further that in the various embodiments and examples of my invention, illustrated and described herein, the specific character of the electronic amplifier tubes employed may be selected at will from among the-various types available, i. e., triodes, tetrodes, pentrodes, beam power tubes and the like.
  • the system of Figure 6 represents a simple variation of the system of Figure 2, demonstrating that, if desired, the bifilar primary windterminals of the voltage supply.
  • 3% ings 85, 38 may be coupled directly to a load, the transformer "r acting as an auto-transformer.
  • Figure 8 illustrating a possible substitute for the system of Figure 7, employing superposed coils in place of bifllarly wound coils,
  • FIG. 8 the transformer of Figure 8 being in some respects equivalent to the transformer of Figure 7, when the windings are properly connected'in a push-pull amplifier arranged in accordance with the invention.
  • Figures 9 and 10 illustrate variants of the transformer of Figure 7 wherein separate layers of a single coil are incorporated by suitable interlayer connections in difi'erent primary windings of a push-pull transformer, providing a true approximate equivalent for a bifilarly wound transformer.
  • Leads 6%, M6 are brought out from the commencement point N3 of the bifilar winding, to which may be connected 3+ and B terminals of a voltage supply, when the transformer is connected in an amplifier circuit.
  • the end of the winding, at point ltd are brought out two terminals 807, E08, intended for connection, respectively, to the plate or anode P1 of one amplifier tube of a push-pull amplifier, and the cathode C2 of the remaining tube.
  • a duplicate coil lie is wound on the same core beside the coil till, having terminals ill and i 52 for connection respectively to 3+ and B and terminals M3, M4 for connection respectively to the cathode Ci of the one tube and the anode P2 of the remaining tube;
  • Secondary windings M5, M6 are superposed on the primary coils wt and iii), respectively, and are shown connected in series by a lead ill, it being understood that parallel connection is equally feasible.
  • bifilar windings are dispensed with, and four primary windings are provided, numbered i20, i2l, 522 and H23.
  • the superposed windings Ho and i2! are wound in mutually identical sense, and the superposed windings I22 and H3 in identical sense, the latter two oppositely to the first mentioned two windings, and the winding pairs are arranged adjacently on the core.
  • the initial point G24 of winding I20 may be connected to terminal IB- and the terminating point I25 of winding I2I' to terminal 3+, of a plate voltage supply source, by appropriate terminals provided, and the terminal points I24 and I25 being thus Joined by a path of negligible A.-C.
  • the terminal point I26 of winding I20 and the initial point I2! of winding I2I are arranged to be in close juxtaposition, and are joined by a condenser Ki, which serves to maintain the points I26 and iZl at identical A.-C. potentials.
  • the terminal point I26 may be connected to cathode C2 and the terminal Ifil to anode PI.
  • the coil I22 may be similarly arranged, terminal I 28 being connected to 13-, terminal I29 of coil I23 to 3+, and terminals H and I3I joined by a condenser K2, so that the terminals of pair I28, I29 and the terminals of pair I30, I3i are at identical A.-C. potentials.
  • Terminal I30 may be connected to cathode CI and terminal I3i'to anode P2, of the tubes of the amplifieremploying the transformer.
  • the secondary winding i232 may be arranged as in the embodiment of Figure 7 of the drawings.
  • leakage inductance in the case of the embodiment of my invention illustrated in Figure 8, will be greater than in the case of the embodiment of Figure 7.
  • the transformer of Figure 8 may conceivably be more economically constructed than the transformer of Figure 7, and may prove desirable for that reason, despite its relatively poorer performance.
  • Figure 9 of the drawings is illustrated a further modification of the system of Figure 7, wherein the effect of a bifilar coil is attained by winding the respective primary windings which are desired to be unity coupled, in successive layers, and joining the layers thereafter by means of suitable leads.
  • the winding 29 may comprise the winding layers I4I, I42, I43, I44, I45, I46, etc., and the winding 30 the alternate layers I41, I46, I49, I50, II
  • the terminal point of layer I4I may be connected 1 to B- and its other end point joined by lead I to an adjacent end point of layer I42, the layers I and I42 being wound in the same direction and current in each turn of both layers Ill and I42 flowing in the same sense, to produce mutually additive flux in the core.
  • the process of layer interconnection is continued to the end of the winding, the winding layers I45, I42, I43 being thus connected in series.
  • the alternate layers, I41, I48, I49 are likewise connected in mutual series relation by leads IN, and a secondary winding I63 may be superposed on the primary windings, in conventional fashion.
  • the terminal points of the outermost pair of adjacent winding layers may then be brought out to anode PI and cathode C2, respectively.
  • a similar pair of primary windings, I54 and I65 may be provided on the core, adjacent to the primary windings 29 and 30, for connection to the anode P2 and the cathode CI, and with the windings 29 and 30 associated a further secondary winding I64, connected in series with secondary winding I63, it being understood that parallel connection is equally feasible.
  • Figiu'e 10 illulstrates a winding sequence which approaches that of the sequence provided in the embodiment of Figure 9 of the drawings, the winding being laid in successive layers, 170 which are left mutually unconnected when the coil is wound.
  • the first. fourth, fifth, eighth, ninth, twelfth .layers are connected in series by leads i6I to provide one winding; the second, third, sixth, seventh, tenth, eleventh layers are connected in series by leads I62 to provide the other winding.
  • the initial points of the first and second layer may be connected respectively to the 23+ and B- terminals of a voltage supply, and the two outermost windings (the eleventh and twelfth layers of a twelve layer winding, for example), connected to the cathode, C2, of one vacuum tube and the anode, Pi, of a further vacuum tube of a push-pull amplifier arranged in accordance with the invention.
  • the latter two terminals may be connected across a condenser K to assure that the same A.-C. potential exists at these terminals, as in the transformer arrangements of Figures 8 and 9, inclusive.
  • the upper windings may be duplicated to provide two pairs of biiilarly wound equivalents.
  • each of the tubes of the amplifiers or modulators disclosed is operated with negative feedback, since' in each case a primary winding of an output transformer is connected in a cathode lead of a tube and the grid-cathode or input circuit is connected across the winding.
  • Each of the tubes is, however, also plate loaded so that part of the output of each tube derives from its plate circuit, and part from the cathode circuit.
  • a push-pull wide band audio frequency amplifier comprising, a first electronic amplifier tube having a first anode, cathode and control electrade, a second electronic amplifier tube having a second anode, cathode and control electrode, a source of anode voltage having a positive and a negative terminal, a magnetic core, first and second primary output transformer windings of substantially equal inductance and having each a high impedance at said audio frequencies, arranged in bifllar relation about said core, means vfor connecting said first winding between said negative terminal and said first cathode, means for connecting said second Winding between said positive terminal and said second anode, third and fourth primary output windings of substantially equal inductance and having each a high impedance at said audio frequencies arranged in bifilar relation about said core, means connecting said third winding between said negative terminal and said second cathode, means for connecting said fourth winding between said positive terminal and said first anode, a secondary winding coupled substantially equally to said first, second, third
  • first amplifier tube comprises a first screen grid
  • second amplifier tube comprises a second screen grid, means for connecting said first screen grid directly to said second anode and means for connecting said second screen grid directly to said first anode.
  • a push-pull wide band audio frequency amplifier comprising, a first electronic amplifier tube having a first anode, cathode and control electrode, a second electronic amplifier tube having a second anode, cathode and control electrode, a source of anode potential having a negative and a positive terminal, an output transformer having a magnetic core, multiturn primary windings of substantially equal inductance and having high impedance at audio frequencies linking said core and coupled to said first and second tubes, said primary windings comprising at least two' closely coupled windings wound' in identical winding sense, means for connecting one of said windings between said negative terminal and said first cathode, means for connecting the other of said windings between said positive terminal and said second anode, said primary windings comprising at least two further closely coupled multiturn windings of substantially equal inductance and having high impedance at audio frequencies linking said core and wound in identical winding sense, opposite to said first mentioned winding sense, means for connecting one of said further windings between said positive terminal and said first
  • first and second electronic amplifier tubes have a first and a second screen grid, respectively, and wherein is provided means for maintaining constant potential between said first screen grid and said first cathode and between said second screen grid and said second cathode, during operation of said amplifier.
  • a wide band amplifier comprising, a first amplifier tube having a first cathode circuit and a first anode circuit, a second amplifier tube having a second cathode circuit and a second anode circuit, an output transformer having a magnetic core, a first pair of unity coupled primary windlugs and a second pair of unity coupled primary windings, both linking said core, means for connecting one of said first pair of windings in said first anode circuit and the other of said first pair of windings in said second cathode circuit, means for connecting one of said second pair of primary windings in said second anode circuit and the other of said second pair of primary windings in said first cathode circuit, a load circuit coupled substantially equally to all said primary windings, means for biasing said amplifier tubes to provide current fiow in at least one of said tubes in response to any finite signal, and a wide band input circuit connected in push-pull relation to said control electrodes for applying said wide band of signals thereto,
  • An amplifier for amplifying a wide band of signals with essentially fiat response comprising, a first electronic amplifier tube having a first anode, cathode and control electrode, a second electronic amplifier tube having a second anode, cathode and control electrode, a source of anode voltage having a positive and a negative termi- 112.1, a magnetic core, first and second primary output windings-arranged in unity coupled relation about said core, each of said windings having an impedance at the low end of said band, which is of the same order of magnitude as the internal resistance of one of said tubes, means for connecting said first winding between said negative terminal and said first cathode, means for connecting said second winding between said positive terminal and said second anode, third and fourth primary output windings arranged in unity coupled relation about said core, said third and fourth primary output windings each substantially duplicating an impedance one of said first and second primary windings, means connecting said third winding between said negative terminal and said second cathode, means for connecting said
  • each of said first and second amplifier tubes comprises a further control electrode.

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US66741A 1948-12-22 1948-12-22 Wide band amplifier coupling circuits Expired - Lifetime US2477074A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
NL737305804A NL150547B (nl) 1948-12-22 Zelfremmend opwikkeldrijfwerk met worm en wormwiel voor een rolluik of dergelijk verticaal beweegbaar afsluitorgaan.
NL79816D NL79816C (en(2012)) 1948-12-22
US66741A US2477074A (en) 1948-12-22 1948-12-22 Wide band amplifier coupling circuits
FR1002802D FR1002802A (fr) 1948-12-22 1949-12-14 Circuits de couplage pour amplificateur à large bande de fréquences
CH296850D CH296850A (fr) 1948-12-22 1949-12-17 Amplificateur à large bande de fréquences.
DEI288D DE842502C (de) 1948-12-22 1949-12-20 Anordnung zur Verstaerkung eines breiten Frequenzbandes mittels im Gegentakt geschalteter, mit aussteuerungsabhaengigem Anodenstrom betriebener Roehren
GB32863/49A GB677921A (en) 1948-12-22 1949-12-22 Improvements in wide band amplifier coupling circuits

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US66741A US2477074A (en) 1948-12-22 1948-12-22 Wide band amplifier coupling circuits

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US2477074A true US2477074A (en) 1949-07-26

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US66741A Expired - Lifetime US2477074A (en) 1948-12-22 1948-12-22 Wide band amplifier coupling circuits

Country Status (6)

Country Link
US (1) US2477074A (en(2012))
CH (1) CH296850A (en(2012))
DE (1) DE842502C (en(2012))
FR (1) FR1002802A (en(2012))
GB (1) GB677921A (en(2012))
NL (2) NL150547B (en(2012))

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2646467A (en) * 1949-07-13 1953-07-21 Frank H Mcintosh Wide band amplifier
US2648727A (en) * 1949-10-04 1953-08-11 Crosley Broadeasting Corp Push-pull wide band amplifier
US2659845A (en) * 1950-02-13 1953-11-17 Wayne Kerr Lab Ltd High-frequency alternating current transformer
US2673328A (en) * 1950-11-18 1954-03-23 Weston Electrical Instr Corp Frequency meter
US2680218A (en) * 1950-10-26 1954-06-01 Acro Products Company Audio transformer
US2704791A (en) * 1949-04-29 1955-03-22 Western Electric Co Push-pull amplifier circuit
US2798202A (en) * 1955-02-14 1957-07-02 Electro Engineering Works Push-pull modulating transformer
US2802907A (en) * 1951-01-22 1957-08-13 Gen Radio Co Distortionless audio amplifier
US2860192A (en) * 1953-05-01 1958-11-11 Frank H Mcintosh Amplifiers
US2871461A (en) * 1953-11-20 1959-01-27 Texas Co Seismic prospecting
US2898399A (en) * 1954-09-14 1959-08-04 Rca Corp Color television receivers
US2930985A (en) * 1957-05-22 1960-03-29 Burroughs Corp Wide-band amplifier
US2980840A (en) * 1958-08-08 1961-04-18 Levy Lester Wide band, low distortion, high efficiency amplifier
US3316504A (en) * 1964-07-17 1967-04-25 Crosley Broadcasting Corp Circuit for extending bandwidth of a modulated amplifier
US4311977A (en) * 1980-05-29 1982-01-19 Continental Electronics Mfg. Co. Output transformer
US5500632A (en) * 1994-05-11 1996-03-19 Halser, Iii; Joseph G. Wide band audio transformer with multifilar winding
US5917396A (en) * 1997-08-04 1999-06-29 Halser, Iii; Joseph G. Wideband audio output transformer with high frequency balanced winding

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2962275B1 (fr) 2010-07-02 2012-07-20 Tekcem Recepteur pour transmission multivoie puce-a-puce en champ proche

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1791236A (en) * 1928-05-04 1931-02-03 Radio Frequency Lab Inc Electrical circuit and transformer therefor
US2187782A (en) * 1935-10-15 1940-01-23 Emi Ltd Thermionic tube modulator

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1791236A (en) * 1928-05-04 1931-02-03 Radio Frequency Lab Inc Electrical circuit and transformer therefor
US2187782A (en) * 1935-10-15 1940-01-23 Emi Ltd Thermionic tube modulator

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2704791A (en) * 1949-04-29 1955-03-22 Western Electric Co Push-pull amplifier circuit
US2646467A (en) * 1949-07-13 1953-07-21 Frank H Mcintosh Wide band amplifier
US2648727A (en) * 1949-10-04 1953-08-11 Crosley Broadeasting Corp Push-pull wide band amplifier
US2659845A (en) * 1950-02-13 1953-11-17 Wayne Kerr Lab Ltd High-frequency alternating current transformer
US2680218A (en) * 1950-10-26 1954-06-01 Acro Products Company Audio transformer
US2673328A (en) * 1950-11-18 1954-03-23 Weston Electrical Instr Corp Frequency meter
US2802907A (en) * 1951-01-22 1957-08-13 Gen Radio Co Distortionless audio amplifier
US2860192A (en) * 1953-05-01 1958-11-11 Frank H Mcintosh Amplifiers
US2871461A (en) * 1953-11-20 1959-01-27 Texas Co Seismic prospecting
US2898399A (en) * 1954-09-14 1959-08-04 Rca Corp Color television receivers
US2798202A (en) * 1955-02-14 1957-07-02 Electro Engineering Works Push-pull modulating transformer
US2930985A (en) * 1957-05-22 1960-03-29 Burroughs Corp Wide-band amplifier
US2980840A (en) * 1958-08-08 1961-04-18 Levy Lester Wide band, low distortion, high efficiency amplifier
US3316504A (en) * 1964-07-17 1967-04-25 Crosley Broadcasting Corp Circuit for extending bandwidth of a modulated amplifier
US4311977A (en) * 1980-05-29 1982-01-19 Continental Electronics Mfg. Co. Output transformer
US5500632A (en) * 1994-05-11 1996-03-19 Halser, Iii; Joseph G. Wide band audio transformer with multifilar winding
US5917396A (en) * 1997-08-04 1999-06-29 Halser, Iii; Joseph G. Wideband audio output transformer with high frequency balanced winding

Also Published As

Publication number Publication date
NL150547B (nl)
FR1002802A (fr) 1952-03-11
GB677921A (en) 1952-08-27
NL79816C (en(2012))
CH296850A (fr) 1954-02-28
DE842502C (de) 1952-06-26

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