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JPS6480196A - Earth start detection circuit - Google Patents

Earth start detection circuit

Info

Publication number
JPS6480196A
JPS6480196A JP23671887A JP23671887A JPS6480196A JP S6480196 A JPS6480196 A JP S6480196A JP 23671887 A JP23671887 A JP 23671887A JP 23671887 A JP23671887 A JP 23671887A JP S6480196 A JPS6480196 A JP S6480196A
Authority
JP
Japan
Prior art keywords
line
earth
arithmetic amplifier
resistor
voltage
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
JP23671887A
Other languages
Japanese (ja)
Inventor
Yozo Iketani
Shinichi Ito
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
Original Assignee
Fujitsu 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 filed Critical Fujitsu Ltd
Priority to JP23671887A priority Critical patent/JPS6480196A/en
Publication of JPS6480196A publication Critical patent/JPS6480196A/en
Pending legal-status Critical Current

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Abstract

PURPOSE:To attain accurate detection of earth start by providing an amplifica tion arithmetic amplifier receiving a voltage obtained from a current detection resistor inserted between a subscriber power supply and a line A and a compari son circuit arithmetic amplifier detecting the output voltage change of the arithmetic amplifier so as to detect earth start by the detection of a current flowing to a resistor. CONSTITUTION:In connecting earth G and a line A by a switch 3, a current flowing to a detection resistor 14 is monitored and a current change is extracted as a voltage Va across the resistor 14 and it is given to a noninverting input and an inverting input of an arithmetic amplifier 11. When the line A is opened, the potential of the line A reaches a subscriber power voltage Vbb and the output of the arithmetic amplifier 11 is the same potential as the reference voltage Vref of the noninverting input. When the earth G is connected to the lien A via a line resistor 13, the voltage across the detection resistor 14 is Va and an output voltage of the arithmetic amplifier 11 is Va.(Rf/Rs) with respect to the reference voltage Vref. The arithmetic amplifier 12 detects the potential difference of Va.(Rf/Rs) to detect the connection of earth to the line A.
JP23671887A 1987-09-21 1987-09-21 Earth start detection circuit Pending JPS6480196A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP23671887A JPS6480196A (en) 1987-09-21 1987-09-21 Earth start detection circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP23671887A JPS6480196A (en) 1987-09-21 1987-09-21 Earth start detection circuit

Publications (1)

Publication Number Publication Date
JPS6480196A true JPS6480196A (en) 1989-03-27

Family

ID=17004746

Family Applications (1)

Application Number Title Priority Date Filing Date
JP23671887A Pending JPS6480196A (en) 1987-09-21 1987-09-21 Earth start detection circuit

Country Status (1)

Country Link
JP (1) JPS6480196A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105403791A (en) * 2015-12-09 2016-03-16 华南理工大学 Device starting detection circuit

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS56106492A (en) * 1980-01-25 1981-08-24 Nec Corp Detection circuit of subscriber's earth

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS56106492A (en) * 1980-01-25 1981-08-24 Nec Corp Detection circuit of subscriber's earth

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105403791A (en) * 2015-12-09 2016-03-16 华南理工大学 Device starting detection circuit

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