US2224915A - Amplifier - Google Patents

Amplifier Download PDF

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Publication number
US2224915A
US2224915A US154152A US15415237A US2224915A US 2224915 A US2224915 A US 2224915A US 154152 A US154152 A US 154152A US 15415237 A US15415237 A US 15415237A US 2224915 A US2224915 A US 2224915A
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US
United States
Prior art keywords
tube
amplifier
tubes
grid
push
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
US154152A
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English (en)
Inventor
Nils E Lindenblad
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
Priority to BE413555D priority Critical patent/BE413555A/xx
Priority claimed from US4474A external-priority patent/US2131566A/en
Application filed by RCA Corp filed Critical RCA Corp
Priority to US154152A priority patent/US2224915A/en
Application granted granted Critical
Publication of US2224915A publication Critical patent/US2224915A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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

Definitions

  • the amplifier of the said invention makes use of thermionic tubes now in commercial use, although certain characteristics of said tubes, such as limited electron emission and large inter-electrode capacity, work Iagainst the operation of said tubes effectively in known circuits over a frequency bandl of less width than the frequency band involved in this invention.
  • my novel circuit a frequency band of extreme width is successfully amplified, and all of the frequencies in said band are ampliiied, substantially the same amount.
  • transformer coupling between the stages must be excluded at least for the time being, because of the limited frequency range which can be passed by transformer coupling means.
  • the amplifier of the presf ent invention is, for reasons also pointed out above, of the push-pull type.
  • the input energy supplied to the amplifier may be supplied from a push-pull source and may be fed in the usual manner to the control grids of the first stage. In many cases, it is necessary to connect the amplifier of the present invention to a singleended stage.
  • Several novel means for adapting the push-pull wide frequency band amplifier described above to connection with a single-ended source have been disclosed in this application.
  • Figure 1 illustrates a thermionic amplifier of the push-pull type comprising several stages nterconnected by the novel network of the present invention.
  • the input is assumed to be taken from a push-pull source, while the voutput circuit of the final stage is arranged to, feed either a push-pull utilization circuit or a ⁇ single-ended circuit.
  • Figures 2 and 3 illustrate amplifiers of the nature illustrated in Figure 1. In Figures 2 and 3, however, a novel means is included for feeding the push-pull amplifier from the output of a single tube or single-ended stage.
  • Figure 4 is a curve illustrating the characteristics vof the amplifier of the present invention.
  • I have shown a cascaded amplifier of the push-pull type, comprising pairs ⁇ of electron discharge tubes 2, 4, 2', li', etc., connected in cascade by way of resistance and capacity networks, as shown.
  • the input of the iirst stage may-be connected to a full wave source.
  • the anode-to-control grid capacity of each stage is as shown neutralized by a capacity NC. ⁇
  • the output of the push-pull amplifier may be connected'to a push-pull ultilization circuit by means of leads represented by the solid lines' 'or to a sin-A gle-ended input by means of one of the said leads and a lead represented by the dotted line.
  • the small capacities C1 are directly connected between the anodes of the tubes 2, 4 and the control grids of the tubes 4', 2', respectively, whereas the large capacities C2 are as shown connected in parallel to the capacity C1 by way of link resistors R1.
  • the succeeding stages are as shown connected in a similar manner.
  • the stray capacities of these condensers not only can be made larger, but it was found advisable and necessary to do so.
  • an additional condenser C3 which is preferably varable. This condenser, which is small in capacity relative to condenser C2, may be connected on either side vof C2 between C2 and ground. In this manner, a ne regulation of the stray capacity may be accomplished.
  • Another reason for the need of the variable capacity C3 is that at the intermediate frequencies of about 100,000 cycles, the amplifier without the use of said capacities gives somewhat higher amplication due to an optimum impedance condition of my simple network without a correct stray capacity of condenser C2. With this condition corrected by means of adjusting the stray capacity, the variation in amplification throughout the whole band between 20 cycles and 1 megacycle was at one time brought below two decibels (:1).
  • a well regulated or steady direct current source B supplying plate current to this type of amplifier.
  • a separate voltage regulator tube RT and the resistor system RS may be connected as shown with the source B.
  • the source B may be a direct current machine or may represent the output of a rectifier connected with a source of alternating current. Grid biasing potentials for the tubes 2',
  • Grid biasing potentials for tubes 2 and 4 may be supplied by the source connected with the cathodes of 2 and 4 by Way of a lead (not shown) connected to a point on the input circuit.
  • terminal circuits be arranged so that this amplifier, which as shown in Figure 1 is assumed to be supplied from a push-pull stage, may be connected also to single ended circuits in such a Way that the push-pull stages receive balanced input.
  • An arrangement for accomplishing this has been shown in Figure 2.
  • the signal is to be supplied from the output of a ⁇ single ended stage between the control grids of one of the tubes 2, 4 and ground as shown by way of the leads marked Input; the signal on the grid of tube 2 modulates or controls the voltage on the plate of tube 2 and this control or variation is opposite in phase to the controlling potentials applied to the grid.
  • This voltage variation or modulation appears across the resistor X connected as shown by way of source Y between the plate of tube 2 and ground.
  • Voltage variations or modulations are :supplied from the resistance or potentiometer X by way of a movable point and a lead to the control grid of tube 4.
  • potentiometer X to the proper position, voltages of an amplitude equal to the amplitude of the voltages on the grid of tube 2 and of a phase opposite in phase to the voltages on the grid Aof tube 2 may be applied to the grid of tube 4 so that we have a true push-pull input.
  • the source Y provides a counterelectromotive force to insure correct direct current voltage on the grid of tube '4.
  • Condensers proportional, in reactance, to the resistance on each si'de of the tapping point may be connected with the resisance X as shown. These condensers, if used,-must be very small.
  • An additional circuit containing a resistor X' may be added to the plate of tube 4 to complete the balance.
  • a converter tube CT may have its control grid and cathode connected as shown to any source of alternating current potential to be amplified. A capacity may be included in this connection.
  • the input line and the control grid of tube CT are also connected as shown by way of a coupling and direct current blocking condenser C5 to the control grid ofv one of the tubes in the rst pushpull stage, as for example tube 2.
  • the grid of the other tube, as for example tube 4, in the rst push-pull stage is supplied by potentials from a potentiometer resistance X connected in series between the plate and the anode source B.
  • the regulator tube RT may be connected with the plate potential source B by way of a resistance system RS, as shown.
  • an electron discharge tube having a control grid, a cathode, and an anode, a connection between the cathode of said tube and said point of xed potential, a condenser connected between said other terminal, the potential of which varies, and the control grid of said tube, a condenser connecting one of said two other terminals and said control grid, an impedance and a source of potential connecting the anode of said tube to the cathode of said tube, a movable point on said impedance, and a condenser coupling the other of said two other terminals to said movable point.
  • an electron discharge tube having an anode, a cathode, and a control grid, a connection between the cathode of said tube and said latter point of xed potential, a condenser coupling said other terminal of said two terminals to the control grid of said tube, a condenser coupling said grid to one of the other two of said three terminals, an impedance connecting the anode of said tube to the cathode of said tube and a condenser coupling an adjustable point on said impedance to the other of the other two of said three terminals.
  • a plurality of .electron discharge tubes each having an anode, a cathode, and a control grid, a connection between the cathode of two of said tubes and said xed point, a condenser coupling said other of said two leads to the control grid of one of said two tubes, a connection between the control grid of a third tube and said other of said two leads, an impedance connecting the anode of said third tube to the cathode of said third tube, a condenser coupling an adjustable point on said impedance to the control grid of the other of said two tubes, and connections between the anodes of said two tubes and said other two terminals.
  • each of said ⁇ last connections include a plurality of parallel paths each responsive to potentials of a diiierent frequency range, the several paths being responsive to a wide frequency range.
  • Means for impressing oscillations from a single ended amplifier stage including a thermionic discharge tube having at least a control grid and anode on the control grids of a pair of thermionic tubes each having at least a control grid and an anode in push-pull fashion in like amounts comprising, a condenser coupling control grid o-f one of said tubes of said pair of thermionic tubes to the control grid of said single-ended stage, a resistance connected to the anode of said single ended stage, and capacitive means coupling a point on said resistance to the control grid of the other tube in said pair of thermionic tubes.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Amplifiers (AREA)
US154152A 1935-02-01 1937-07-17 Amplifier Expired - Lifetime US2224915A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
BE413555D BE413555A (en)van) 1935-02-01
US154152A US2224915A (en) 1935-02-01 1937-07-17 Amplifier

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US4474A US2131566A (en) 1935-02-01 1935-02-01 Amplifier
US154152A US2224915A (en) 1935-02-01 1937-07-17 Amplifier

Publications (1)

Publication Number Publication Date
US2224915A true US2224915A (en) 1940-12-17

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US154152A Expired - Lifetime US2224915A (en) 1935-02-01 1937-07-17 Amplifier

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BE (1) BE413555A (en)van)

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Publication number Publication date
BE413555A (en)van)

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