US1944746A - Audio-frequency amplifier - Google Patents

Audio-frequency amplifier Download PDF

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Publication number
US1944746A
US1944746A US356712A US35671229A US1944746A US 1944746 A US1944746 A US 1944746A US 356712 A US356712 A US 356712A US 35671229 A US35671229 A US 35671229A US 1944746 A US1944746 A US 1944746A
Authority
US
United States
Prior art keywords
amplifier
audio
resistor
condenser
tube
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
US356712A
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English (en)
Inventor
Vernon D Landon
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.)
Westinghouse Electric Corp
Original Assignee
Westinghouse Electric 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 NL32140D priority Critical patent/NL32140C/xx
Application filed by Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Priority to US356712A priority patent/US1944746A/en
Application granted granted Critical
Publication of US1944746A publication Critical patent/US1944746A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/01—Frequency selective two-port networks
    • H03H7/0138—Electrical filters or coupling circuits
    • H03H7/0146—Coupling circuits between two tubes, not otherwise provided for
    • 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
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/01—Frequency selective two-port networks
    • H03H7/17—Structural details of sub-circuits of frequency selective networks
    • H03H7/1741—Comprising typical LC combinations, irrespective of presence and location of additional resistors
    • H03H7/1775—Parallel LC in shunt or branch path

Definitions

  • My invention relates to amplifiers and it has particular relation to audio-frequency amplifiers of the impedance, or resistance-coupled type.
  • an object of my invention to provide an impedance-coupled amplifier having a characteristic curve that is substantially fiat between and 5000 cycles.
  • Another object of my invention is to provide a system of impedance-coupling particularly useful in connection with tubes of the four-electrode type.
  • Another object of my invention is to reduce the size of the choke-core necessary to obtain the above results.
  • Another object of my invention is to produce a peak in the response curve of an amplifier in the neighborhood of 100 cycles, when this seems desirable by reason of deficiencies in other parts of the apparatus.
  • I connect a resistor in shunt relation to the coupling-choke in an impedance-coupled amplifier in order to reduce the amplification at the higher frequencies.
  • the resistor also tends to lower the amplification at frequencies in the neighborhood of 100 cycles and, for that reason, I find it advisable to insert a small condenser in series therewith.
  • the reactance of the condenser is substantially negligible at the higher frequencies, but it is sufiicient to raise the lowfrequency response of the amplifier to a satisfactory degree.
  • Figure 1 is a diagrammatic view of a portion of a signal-reception system comprising a preferred embodiment of my invention.
  • Fig. 2 is a diagram to which reference will later be made in explaining the theory underlying my invention.
  • the apparatus illustrated in Fig. 1 comprises a thermionic detector tube 1 and a thermionic amplifier tube 2 each having an equi-potential cathode 3, aplurality of grids 4 and 5 and a plate 6.
  • the cathodes may be heated from any convenient source of either alternating current or direct current.
  • the tube 1 is provided with a tunable input circuit, constituted by an inductor '7 and a tuning condenser 8 which circuit may be coupled to, any convenient source 10 of incoming high-frequency signals.
  • a biasing battery 11 is provided, whereby the grid potential thereof may be so adjusted that the output current therefrom is distorted.
  • the detector tube is provided with a source 12 of plate potential, the positive terminal of which is connected to the plate through an output inductor 13.
  • the shield grid 5 of the detector tube is connected to an intermediate point on the plate-potential source in a manner well known to those skilled in the art.
  • the output circuit of the detector tube is coupled to the control grid 4 of the amplifier tube 2 through a stopping condenser 14.
  • the amplifier tube is provided with a gridbiasing battery 15, the negative terminal of which is connected to the grid 4 through a resistor 16 of the order of several megohms.
  • the output circuit of the amplifier tube comprises the primary winding of an audio-frequency transformer 17, or it may, if additional stages are to be used, comprise a coupling-choke (not shown) analogous to the choke which constitutes the output circuit of the detector tube.
  • a source 18 of plate potential is provided for the audio-frequency amplifier tube, which source, in commercial radio receiving sets, would be the same as that provided for the detector tube.
  • the shield grid 5 of the amplifier tube is connected to an intermediate point on the platepotential source.
  • the amplifier thus far described is of the wellknown impedance-coupled type exemplified by the British patent to H. Green, No. 241,257 and, inasmuch as the coupling choke has a reactance which increases with frequency, the said amplifier tends to unduly accentuate audio frequencies of the order of 5,000 cycles and higher.
  • a resistor 20, of the order of megohln may be connected in shunt to the coupling choke and, if this is done, the response of the amplifier is of the type illustrated by the curve B in Fig. 2.
  • sion of the relatively inexpensive resistor and condenser in shunt to the coupling reactor permits a marked reduction in size of the latter, with a consequent lowering of the cost of manufacture of the amplifier.
  • a thermionic device havin an output circuit constituted by an inductor having a reactance of substantially 200,000 ohms at 100 cycles, and a resistor of the order of one-quarter megohms and a condenser of the order of .005 microfarad connected serially in shunt to said inductor, said shunt connection being substantially devoid of inductance.
  • a thermionic device having an output circuit constituted by aninductor, a resistor and a capacitor connected serially in shunt with said inductor the reactance of said inductor at 100 cycles being substantially fourfifths of the ohmic resistance of said resistor, said shunt circuit being substantialls devoid of inductance.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Amplifiers (AREA)
US356712A 1929-04-20 1929-04-20 Audio-frequency amplifier Expired - Lifetime US1944746A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
NL32140D NL32140C (enrdf_load_stackoverflow) 1929-04-20
US356712A US1944746A (en) 1929-04-20 1929-04-20 Audio-frequency amplifier

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US356712A US1944746A (en) 1929-04-20 1929-04-20 Audio-frequency amplifier

Publications (1)

Publication Number Publication Date
US1944746A true US1944746A (en) 1934-01-23

Family

ID=23402622

Family Applications (1)

Application Number Title Priority Date Filing Date
US356712A Expired - Lifetime US1944746A (en) 1929-04-20 1929-04-20 Audio-frequency amplifier

Country Status (2)

Country Link
US (1) US1944746A (enrdf_load_stackoverflow)
NL (1) NL32140C (enrdf_load_stackoverflow)

Also Published As

Publication number Publication date
NL32140C (enrdf_load_stackoverflow)

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