US1986554A - Direct coupled amplifier - Google Patents

Direct coupled amplifier Download PDF

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Publication number
US1986554A
US1986554A US548664A US54866431A US1986554A US 1986554 A US1986554 A US 1986554A US 548664 A US548664 A US 548664A US 54866431 A US54866431 A US 54866431A US 1986554 A US1986554 A US 1986554A
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US
United States
Prior art keywords
valve
voltage
feed
feed device
cathode
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
US548664A
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English (en)
Inventor
Brink Barend Albert Jan Ten
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.)
HEINRICH WILLEM KAREL DE BREY
Original Assignee
HEINRICH WILLEM KAREL DE BREY
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
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Publication of US1986554A publication Critical patent/US1986554A/en
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Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/06—Receivers
    • H04B1/16—Circuits
    • H04B1/1607—Supply circuits
    • H04B1/1623—Supply circuits using tubes
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/42—Modifications of amplifiers to extend the bandwidth
    • H03F1/48—Modifications of amplifiers to extend the bandwidth of aperiodic amplifiers
    • H03F1/50—Modifications of amplifiers to extend the bandwidth of aperiodic 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
    • H03F3/20—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

  • the invention relates toelectrical amplifiers and more, particularlyto direct-coupled electrical amplifiers or so-called direct-current amplifiers,
  • the e gpressionffeed device as hereafter used is meantasourcegof current fromwhich tappings can be taken only by means ota resistance. connected inparallel with it.- Snch a-resistance, however, will'invariably introduce thefdrift effect, referred to hereinafter on page 2,; paragraph, 2, of the specification.
  • the great advantage of the invention is that although feed ⁇ devicesare used for, the current supply the circuit arrangement of these feed devices is such that resistances for tapping of suitable working voltage ion the individual tubes are not necessary.
  • Figures 2 and 3 illustrate aiagrammaucau twc examples of an arrangement of direct-coupled amplifier in accordance with theinvention.
  • the grid of the second .valve obviously, has the, same voltage as the anode of the first valve.
  • This grid, thereforacompared with the corresponding cathode, should be negative, this being necessary for f distortionless amplification,
  • neither of the two valves utilizes the whole of the voltage generated between the terminals A, A, a
  • the basis of the invention is formed by the recognition that there are various advantages in-supplying to the first valve a considerably higher (e. g. twice or several times'highem voltage than to the second valve.
  • a considerably higher e. g. twice or several times'highem voltage than to the second valve.
  • the first valve ;.there is clearly apart of the feed voltage lost in the coupling resistance. and this part is greater theigreater is 40 chosenthe coupling resistance with the object of obtaining .a higher, amplification;
  • the significance off this loss is reduced not only for the reason that the valve itselihas at its disposal a sufiicient voltage in order to ,be able to work under favourable condi tions, but there moreover arises the possibility of employing a coupling element whose resistance is largefcompared with the internal resistance of the valve and which is so suited to this valve. that the, distortionless amplification attained reaches a very much higher value than in known circuits.
  • the arrangement according to thein vention isof far reaching significance, especially if the first amplification stage is equipped with a screened grid valve, which in general has a considerably higher internal resistance than a threeelectrode valve.
  • the raising of the feed voltage of the first valve is attained, according to the invention, in that, besides the usual feed device, there is employed afeedhdevioewhose voltage; for the first valve, is added to that of the existing feed device and which, however, supplies no energy to the second valve. There is thereby the ,fur ther possibility of employing the whole voltage cf the usual feed device for supplying the secondva1ye and thereby to amplify without distbrtionagreate energy.
  • Figure Z represents adii ec'te' current amplifier consisting of 'two'valves with an indirectly-heated screen-grid valve I, which is connected by means of va coupling resistance 1 withIa threeaelectrode valve II, 'i Sarje' theinput terminals, and 17, the output terminals 'of the amplifier which "are connected to the, arrangement through a transformer'lfi.
  • a small out first va e Forf'eeding the two valves there are provided rv a small out first va e according to the invention, two feed devices A and B (which are surrounded with dotted lines) and each assumed to consist of a transformer fed from the mains, with an appropriate rectifier.
  • the feed device A consists of the transformer 4 and a rectifier 6, the feed device B of the transformer 3 and the rectifier. 5.
  • Thetwofeed devices are connectedwith one another-at the point 2 and are connected to the two valvesin such a zmanner that there is fed to the anode circuit of the valve, l the sum of the two voltages, but to the anodecir'cuit of the valve 2, onl; the voltage of the feeel device;B, Ete ckoned from the point 2 outwards-,athe.
  • twofeed devices therefore generate er grid amplitude and to obtain a greater ohtputf opposed voltages.
  • a smoothing circuit is connected with the feed device A which is formed by a resistance 11 and the choked and two condensers 8 and '8 and the other of two resistances "9 and 9' and two condensers 10 and 10''.
  • the direct voltage of the point E is therefore again positive compared with that of the point D.
  • valve II it isseen that this receives between thecathodeiand the output transformer 16, a feed voltage afforded only and deter mined by the feed device
  • the anode'conduc tor 18 is connected with the output circuit of the feed device B behind thefirstsmoothi'ng circuit 7, 8, 8'; the smoothing jc irc'uit 9, 9', 10, 10' infiuences, therefore, only the anode current of the valve 1.
  • the reason of this connection will be more fully explained below.
  • the cathode of the valve II has a positive voltage compared withthat or the valveI which is approximately equalto the voltageof the fee deviceA.
  • I I I The negative grid bias of the valve II is obtained by virtue of the fact that in the coupling resistance 1 there is'produced such a drop of potential that the potential ofjthe'anode'of the valve I is somewhat lower than'that of the cathode of the valveII or thatofthepoint of connection 2 of the two feed devices 'A and B.
  • the screen grid of the valve I is'only'fedfrorn the feed device A and assumes through the drop of potential in the resistance 19 a potential which is again somewhat lower than the anode potential of this valve.
  • valve I as well as the valve II receives a feed voltagewhich ensures an optimum for the amplification under the special'circumstancesdetermined for these valves.
  • the direct voltage afforded'by the feed device A will be approximately equal to the peak value of thevoltw age generated in the secondary winding of the transformer 3.
  • one isiin" a position to adapt the icouplingu'esistance 1 in an appropriate manner to the valve I.
  • the feed device B is provided with two smoothing circuits for the reason that practice has shown that thefeed current of the valve I should be according to Figure 2.
  • V Figure 3 represents a somewhatldifierentcircuit arrangement of the direct-coupled amplifier according to the invention in which a simplification has been provided in the formation of the two feed devices, whereby the cost of the arrangement is reduced. The operation otherwise agrees completely with that of the arrangement In the'arrangement of Figure 3, the two recti bombs 5 and 6 are connected with the secondary;
  • the two feed devices A and B are, as it were, connected with one another, whereby one transformer is saved.
  • the low loading of the rectifier 5 for the feeding of the valve I makes this change possible without further ado.
  • a tapping-off switch is provided between the rectifier and the secondary winding of the transformer 4.
  • valve I may act not only as amplifier but also as detector.
  • a direct coupled electric amplifier comprising a first valve and a secondvalve, a high voltage feeddevice comprising a rectifier and having its terminals connectedwith the cathode of the first valve'and the anodes of both valves respectively, an additional feed device comprising a rectifier and having its terminals connected with the cathode of the first valve and the cathode of the second valve respectively, said additional feed device having a connection for the anode of the first valve through the high voltage feed device.
  • a direct-coupled electrical amplifier comprising two valves, a high voltage feed device, an additional feed device, a connection between the two. devices, the common point of connection between the two devices being connected to the cathode of one of the valves, the opposite terminal of the high voltage feed device being connected to the anodes of the two valves, the opposite terminal of the additional feed device heingconnected to the cathode of the other valve, and smoothing circuits interposed in the connections from said opposite terminals.
  • a direct coupled electrical amplifier accord ing to claim '3 in which'the high voltage feed device emdthe' additional feefi device comprise 9L" c'bmmen secondary winding ore; fee'd transformer and two separate rectifiers,one end of salidiwind-T ing' beingconnectedfio the cathode of onebf the valves-and other points df said Winding beingconncted'to the anode 'of one rectifier and to the cathode of the other rectifier respectively;
  • the high voltage feed device emdthe' additional feefi device comprise 9L" c'bmmen secondary winding ore; fee'd transformer and two separate rectifiers,one end of salidiwind-T ing' beingconnectedfio the cathode of onebf the valves-and other points df said Winding beingconncted'to the anode 'of one rectifier and to the cathode of the other rectifier respectively;

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Amplifiers (AREA)
  • Air Bags (AREA)
US548664A 1930-07-11 1931-07-03 Direct coupled amplifier Expired - Lifetime US1986554A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL365011X 1930-07-11

Publications (1)

Publication Number Publication Date
US1986554A true US1986554A (en) 1935-01-01

Family

ID=19785468

Family Applications (1)

Application Number Title Priority Date Filing Date
US548664A Expired - Lifetime US1986554A (en) 1930-07-11 1931-07-03 Direct coupled amplifier

Country Status (5)

Country Link
US (1) US1986554A (en(2012))
DE (1) DE619231C (en(2012))
FR (1) FR719189A (en(2012))
GB (1) GB365011A (en(2012))
NL (1) NL31404C (en(2012))

Also Published As

Publication number Publication date
GB365011A (en) 1932-01-14
NL31404C (en(2012))
FR719189A (fr) 1932-02-02
DE619231C (de) 1935-09-27

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