JPS55154867A - Current supply circuit for telephone switchboard - Google Patents

Current supply circuit for telephone switchboard

Info

Publication number
JPS55154867A
JPS55154867A JP6263979A JP6263979A JPS55154867A JP S55154867 A JPS55154867 A JP S55154867A JP 6263979 A JP6263979 A JP 6263979A JP 6263979 A JP6263979 A JP 6263979A JP S55154867 A JPS55154867 A JP S55154867A
Authority
JP
Japan
Prior art keywords
load
current
subscriber
supply circuit
terminals
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.)
Granted
Application number
JP6263979A
Other languages
Japanese (ja)
Other versions
JPS5930357B2 (en
Inventor
Tetsuo Takeshita
Yoshinori Oikawa
Takehiko Tsutsumi
Koichi Hasegawa
Haruki Fukuda
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.)
Fujitsu Ltd
Hitachi Ltd
NEC Corp
Nippon Telegraph and Telephone Corp
Oki Electric Industry Co Ltd
Original Assignee
Fujitsu Ltd
Hitachi Ltd
NEC Corp
Nippon Telegraph and Telephone Corp
Oki Electric Industry Co Ltd
Nippon Electric Co Ltd
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 Fujitsu Ltd, Hitachi Ltd, NEC Corp, Nippon Telegraph and Telephone Corp, Oki Electric Industry Co Ltd, Nippon Electric Co Ltd filed Critical Fujitsu Ltd
Priority to JP54062639A priority Critical patent/JPS5930357B2/en
Publication of JPS55154867A publication Critical patent/JPS55154867A/en
Publication of JPS5930357B2 publication Critical patent/JPS5930357B2/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M19/00—Current supply arrangements for telephone systems
    • H04M19/001—Current supply source at the exchanger providing current to substations
    • H04M19/005—Feeding arrangements without the use of line transformers

Landscapes

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

Abstract

PURPOSE:To supply a constant current to a subscriber with a loop resistance more than a fixed value while supplying an operating current from an antiside tone varister in a telephone set to a short-distance subscriber, by providing an output voltage detecting circuit with a Zener diode. CONSTITUTION:A load (e.g, subscriber's line) between load terminals 5 and 5' is supplied with currents from current-supplying current amplifiers 1 and 1'. Fluctuations of a voltage between terminals 5 and 5' are detected by output voltage detecting circuit 3. Circuit 3 is provided with Zener diode ZD1, which starts operating when the voltage between the load terminals exceeds a fixed value. As a result, the negative feedback ratio of the negative feedback loop formed of R3, R7, D2, Q3(Q3'), Q2(Q2'), and Q1 becomes zero, so that a constant current will be supplied to the load.
JP54062639A 1979-05-23 1979-05-23 Current supply circuit for telephone exchange Expired JPS5930357B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP54062639A JPS5930357B2 (en) 1979-05-23 1979-05-23 Current supply circuit for telephone exchange

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP54062639A JPS5930357B2 (en) 1979-05-23 1979-05-23 Current supply circuit for telephone exchange

Publications (2)

Publication Number Publication Date
JPS55154867A true JPS55154867A (en) 1980-12-02
JPS5930357B2 JPS5930357B2 (en) 1984-07-26

Family

ID=13206090

Family Applications (1)

Application Number Title Priority Date Filing Date
JP54062639A Expired JPS5930357B2 (en) 1979-05-23 1979-05-23 Current supply circuit for telephone exchange

Country Status (1)

Country Link
JP (1) JPS5930357B2 (en)

Also Published As

Publication number Publication date
JPS5930357B2 (en) 1984-07-26

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