GB679875A - Improvements in or relating to an arrangement for telephone subscribers sets - Google Patents

Improvements in or relating to an arrangement for telephone subscribers sets

Info

Publication number
GB679875A
GB679875A GB6139/50A GB613950A GB679875A GB 679875 A GB679875 A GB 679875A GB 6139/50 A GB6139/50 A GB 6139/50A GB 613950 A GB613950 A GB 613950A GB 679875 A GB679875 A GB 679875A
Authority
GB
United Kingdom
Prior art keywords
microphone
subscriber
transistor
line
march
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
Application number
GB6139/50A
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.)
Siemens and Halske AG
Siemens AG
Original Assignee
Siemens and Halske AG
Siemens AG
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 Siemens and Halske AG, Siemens AG filed Critical Siemens and Halske AG
Publication of GB679875A publication Critical patent/GB679875A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/181—Low-frequency amplifiers, e.g. audio preamplifiers
    • H03F3/183—Low-frequency amplifiers, e.g. audio preamplifiers with semiconductor devices only
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/58—Anti-side-tone circuits

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Multimedia (AREA)
  • Power Engineering (AREA)
  • Devices For Supply Of Signal Current (AREA)

Abstract

679,875. Substation circuits. SIEMENS & HALSKE AKT.-GES. March 10, 1950 [March 16, 1949], No. 6139/50. Class 40 (iv). [Also in Group XL (c)] A transistor amplifier comprising a germanium disc having two tungsten point electrodes is provided in a telephone subscriber's set, the microphone being connected to the emitter electrode, and the collector and base electrodes of the transistor being connected between the speech wires of the subscriber's line. The microphone M is connected between the emitter electrode E, and the subscriber's line b and the amplified output from the collector electrode E is applied to the common point of coils I and II forming part of transformer S which feeds the receiver F. The bias potentials for the transistor are supplied from the exchange battery via the subscribers' lines, the bias for the emitter being due to the current through resistance wi. The provision of resistance R enables the line current to be adjusted to a value suitable for operating relays at the exchange. Network N is provided so that signals from the microphone M do not appear in the receiver F.
GB6139/50A 1949-03-16 1950-03-10 Improvements in or relating to an arrangement for telephone subscribers sets Expired GB679875A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE679875X 1949-03-16

Publications (1)

Publication Number Publication Date
GB679875A true GB679875A (en) 1952-09-24

Family

ID=6594545

Family Applications (1)

Application Number Title Priority Date Filing Date
GB6139/50A Expired GB679875A (en) 1949-03-16 1950-03-10 Improvements in or relating to an arrangement for telephone subscribers sets

Country Status (1)

Country Link
GB (1) GB679875A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1031357B (en) * 1954-02-08 1958-06-04 Int Standard Electric Corp Circuit arrangement for telephone stations with Rückhoerdaempfung and transistor amplifiers
DE1076188B (en) * 1955-09-20 1960-02-25 Sodeco Compteurs De Geneve Circuit arrangement for telephone subscriber stations equipped with fee displays
DE1093416B (en) * 1954-10-06 1960-11-24 Automatic Elect Lab Circuit arrangement for exchange-powered telephone subscriber sets with transistor speech amplifiers
DE1096423B (en) * 1954-10-08 1961-01-05 Western Electric Co Circuit arrangement for telephone subscriber stations with transistor amplifiers
DE1100702B (en) * 1954-12-30 1961-03-02 Western Electric Co Circuit arrangement for telephone subscriber stations with a transistor amplifier fed from the office battery

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1031357B (en) * 1954-02-08 1958-06-04 Int Standard Electric Corp Circuit arrangement for telephone stations with Rückhoerdaempfung and transistor amplifiers
DE1093416B (en) * 1954-10-06 1960-11-24 Automatic Elect Lab Circuit arrangement for exchange-powered telephone subscriber sets with transistor speech amplifiers
DE1096423B (en) * 1954-10-08 1961-01-05 Western Electric Co Circuit arrangement for telephone subscriber stations with transistor amplifiers
DE1100702B (en) * 1954-12-30 1961-03-02 Western Electric Co Circuit arrangement for telephone subscriber stations with a transistor amplifier fed from the office battery
DE1076188B (en) * 1955-09-20 1960-02-25 Sodeco Compteurs De Geneve Circuit arrangement for telephone subscriber stations equipped with fee displays

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