JPS57155868A - Error current correcting circuit - Google Patents

Error current correcting circuit

Info

Publication number
JPS57155868A
JPS57155868A JP4034681A JP4034681A JPS57155868A JP S57155868 A JPS57155868 A JP S57155868A JP 4034681 A JP4034681 A JP 4034681A JP 4034681 A JP4034681 A JP 4034681A JP S57155868 A JPS57155868 A JP S57155868A
Authority
JP
Japan
Prior art keywords
current
circuit
subscriber
voltage
measuring
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.)
Pending
Application number
JP4034681A
Other languages
Japanese (ja)
Inventor
Tetsuya Kono
Kaneichi Otsuki
Shiro Yokota
Shigeru Yoshida
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.)
Hitachi Ltd
Nippon Telegraph and Telephone Corp
Original Assignee
Hitachi Ltd
Nippon Telegraph and Telephone 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
Application filed by Hitachi Ltd, Nippon Telegraph and Telephone Corp filed Critical Hitachi Ltd
Priority to JP4034681A priority Critical patent/JPS57155868A/en
Publication of JPS57155868A publication Critical patent/JPS57155868A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M3/00—Automatic or semi-automatic exchanges
    • H04M3/22—Arrangements for supervision, monitoring or testing
    • H04M3/26—Arrangements for supervision, monitoring or testing with means for applying test signals or for measuring
    • H04M3/28—Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor
    • H04M3/30—Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor for subscriber's lines, for the local loop

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Monitoring And Testing Of Exchanges (AREA)

Abstract

PURPOSE:To achieve a circuit which can measure an insulating resistance of subscriber lines from a scale of an ammeter, by providing a correction circuit at the station side to correct a switch driving current, when a semiconductor switch is used for a test use service entrance switch at a telephone subscriber terminal side. CONSTITUTION:In measuring an insulating resistance 1 of a subscriber line, a driving current Ig of a service entrance switch 2 is superimposed on a current IL to be obtained. On the other hand, when two types of power supply circuits 5 (voltage VB) and 6 (voltage VB/2) are connected to the subscriber lines, a voltage V7 from the current Ig in the relation as shown in figure can be known from voltages V5 and V6 proportional to a current given to a correction circuit 4 in response to the VB and VB/2. This operation is made at an operation circuit and a current corresponding to the obtained V7 is given to a correction circuit side 4 via a transistor 16 and a resistor 17 at the test of subscriber. Then, the scale of an ammeter A of the said measuring circuit 3 indicates the measuring current LL to be obtained actually, allowing to measure the insuration resistance 1 correctly.
JP4034681A 1981-03-23 1981-03-23 Error current correcting circuit Pending JPS57155868A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP4034681A JPS57155868A (en) 1981-03-23 1981-03-23 Error current correcting circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP4034681A JPS57155868A (en) 1981-03-23 1981-03-23 Error current correcting circuit

Publications (1)

Publication Number Publication Date
JPS57155868A true JPS57155868A (en) 1982-09-27

Family

ID=12578068

Family Applications (1)

Application Number Title Priority Date Filing Date
JP4034681A Pending JPS57155868A (en) 1981-03-23 1981-03-23 Error current correcting circuit

Country Status (1)

Country Link
JP (1) JPS57155868A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6424433B1 (en) 1997-06-20 2002-07-23 Pfu Limited Original reader

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6424433B1 (en) 1997-06-20 2002-07-23 Pfu Limited Original reader

Similar Documents

Publication Publication Date Title
US5006809A (en) Apparatus for measuring the electrical resistance of a test specimen
FR2254168A1 (en) Telephone line supply device - is an active electronic device acting as resistance for direct current and high impedance for A.C.
JPS57155868A (en) Error current correcting circuit
EP0061189A1 (en) Subscriber line testing system
GB1463904A (en) Electric contact testing circuits
US3445769A (en) Method and apparatus for in-circuit semiconductor characteristic measurements by establishing a predetermined voltage across the semiconductor and an externally connected impedance
JPS57194325A (en) Multipoint temperature measuring device
US3832633A (en) Transistor beta measuring instrument
SU1551979A1 (en) Simulator of discrete increment of resistance of strain gauge
JPH0546506B2 (en)
JPH04315062A (en) Method for measuring resistance value of resistor
JPS57154069A (en) Measuring device for electric resistance
SU769452A1 (en) Multi-limit electric resistance simulator
SU1142882A1 (en) Charge amplifier
SU978055A1 (en) Current to voltage converter
JP2727324B2 (en) Resistance network analyzer
SU1133558A2 (en) Device for compensating progressing error of electric circuit
SU1241151A2 (en) Device for measuring resistance of resistors connected in "blind" star
JPS55107962A (en) Megger
JPS5614160A (en) Clip
KR830000862B1 (en) megger
KR930005367Y1 (en) Three line type resistance testing circuit
JPS6463877A (en) Earthing resistance measuring apparatus
JPS5635030A (en) Temperature measuring apparatus
JPS5457144A (en) Overcurrent detector