JPS54103658A - Protective circuit - Google Patents

Protective circuit

Info

Publication number
JPS54103658A
JPS54103658A JP928378A JP928378A JPS54103658A JP S54103658 A JPS54103658 A JP S54103658A JP 928378 A JP928378 A JP 928378A JP 928378 A JP928378 A JP 928378A JP S54103658 A JPS54103658 A JP S54103658A
Authority
JP
Japan
Prior art keywords
voltage
positive feedback
circuit
trq3
input
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
JP928378A
Other languages
Japanese (ja)
Inventor
Kazuo Watanabe
Masanori Ienaka
Masahiro Yamamura
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
Original Assignee
Hitachi 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 Hitachi Ltd filed Critical Hitachi Ltd
Priority to JP928378A priority Critical patent/JPS54103658A/en
Publication of JPS54103658A publication Critical patent/JPS54103658A/en
Pending legal-status Critical Current

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  • Amplifiers (AREA)
  • Circuit For Audible Band Transducer (AREA)

Abstract

PURPOSE: To increase the response velocity, to ensure an accurate setting of protective action point and also the prevent the malfunction by using the positive feedback circuit for the amplifier circuit which receives the output signals of the fault detector circuit.
CONSTITUTION: With increment of input voltage VIN, the collector potential of transistor TrQ3. And TrQ4 is switched off with TrQ5 switched on respectively, and output voltage VOUT is lowered. As a result, the current of positive feedback circuit 6 decreases, and accordingly the collector potential of TrQ3 decreases quickly. With decrement of input voltage VIN, output voltage VOUT is changed to a high level contrarily, and thus the positive feedback voltage to TrQ3 is increased quickly at input voltage VT2. TrQ1 and Q2 operated according to the change of the output voltage, and thus the voltage of coil 5 varies suddenly. Thus, contact SW is opened to protect both the circuit and the load in case the abnormal voltage is detected. At the same time, the input threshold voltage features VT1 and VT2 plus the hysteresis characteristics due to the value of the positive feedback current.
COPYRIGHT: (C)1979,JPO&Japio
JP928378A 1978-02-01 1978-02-01 Protective circuit Pending JPS54103658A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP928378A JPS54103658A (en) 1978-02-01 1978-02-01 Protective circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP928378A JPS54103658A (en) 1978-02-01 1978-02-01 Protective circuit

Publications (1)

Publication Number Publication Date
JPS54103658A true JPS54103658A (en) 1979-08-15

Family

ID=11716138

Family Applications (1)

Application Number Title Priority Date Filing Date
JP928378A Pending JPS54103658A (en) 1978-02-01 1978-02-01 Protective circuit

Country Status (1)

Country Link
JP (1) JPS54103658A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57142009A (en) * 1981-02-27 1982-09-02 Nec Corp Protection circuit
JPS6230411U (en) * 1985-08-08 1987-02-24
JPH03256533A (en) * 1990-03-02 1991-11-15 Shikoku Sogo Kenkyusho:Kk System linkage system
JPH0888937A (en) * 1994-09-16 1996-04-02 Nishishiba Electric Co Ltd Grid interconnection protection device

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57142009A (en) * 1981-02-27 1982-09-02 Nec Corp Protection circuit
JPS6230411U (en) * 1985-08-08 1987-02-24
JPH03256533A (en) * 1990-03-02 1991-11-15 Shikoku Sogo Kenkyusho:Kk System linkage system
JPH0888937A (en) * 1994-09-16 1996-04-02 Nishishiba Electric Co Ltd Grid interconnection protection device

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