GB1437874A - Opto-couplers - Google Patents

Opto-couplers

Info

Publication number
GB1437874A
GB1437874A GB3387674A GB3387674A GB1437874A GB 1437874 A GB1437874 A GB 1437874A GB 3387674 A GB3387674 A GB 3387674A GB 3387674 A GB3387674 A GB 3387674A GB 1437874 A GB1437874 A GB 1437874A
Authority
GB
United Kingdom
Prior art keywords
coupler
opto
transistor
resistor
protected
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
GB3387674A
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.)
Post Office
Original Assignee
Post Office
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 Post Office filed Critical Post Office
Priority to GB3387674A priority Critical patent/GB1437874A/en
Publication of GB1437874A publication Critical patent/GB1437874A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/08—Modifications for protecting switching circuit against overcurrent or overvoltage
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
    • H03K17/78—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used using opto-electronic devices, i.e. light-emitting and photoelectric devices electrically- or optically-coupled
    • H03K17/795—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used using opto-electronic devices, i.e. light-emitting and photoelectric devices electrically- or optically-coupled controlling bipolar transistors
    • H03K17/7955—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used using opto-electronic devices, i.e. light-emitting and photoelectric devices electrically- or optically-coupled controlling bipolar transistors using phototransistors

Abstract

1437874 Transistor switching circuits POST OFFICE 31 July 1974 33876/74 Heading H3T A light emitting diode type of opto-coupler is protected by a circuit limiting the maximum current through the coupler to a predetermined value, I oc , set by a resistor 2, of value R, and the emitter-base voltage, V BE at which a transistor 3 becomes conductive. I OC =V BE /R. As the current through the light-emitting diode, forming part of the opto-coupler, increases so the voltage drop across resistor 2 rises until the transistor turns on to shunt further current around the diode. The protected opto-coupler may be used to form a D-relay (Fig. 2, not shown) which can be used in a register access relay set of a telephone exchange.
GB3387674A 1974-07-31 1974-07-31 Opto-couplers Expired GB1437874A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB3387674A GB1437874A (en) 1974-07-31 1974-07-31 Opto-couplers

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB3387674A GB1437874A (en) 1974-07-31 1974-07-31 Opto-couplers

Publications (1)

Publication Number Publication Date
GB1437874A true GB1437874A (en) 1976-06-03

Family

ID=10358613

Family Applications (1)

Application Number Title Priority Date Filing Date
GB3387674A Expired GB1437874A (en) 1974-07-31 1974-07-31 Opto-couplers

Country Status (1)

Country Link
GB (1) GB1437874A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2146187A1 (en) * 1998-12-04 2000-07-16 Disseny Electronic Integral S Telephone line protector
GB2440186A (en) * 2006-07-14 2008-01-23 Wolfson Microelectronics Plc Light source protection circuit
WO2009000325A1 (en) * 2007-06-26 2008-12-31 Osram Gesellschaft mit beschränkter Haftung Circuit for driving an electro-optical transducer
US7884557B2 (en) 2006-07-14 2011-02-08 Wolfson Microelectronics Plc Protection circuit and method

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2146187A1 (en) * 1998-12-04 2000-07-16 Disseny Electronic Integral S Telephone line protector
GB2440186A (en) * 2006-07-14 2008-01-23 Wolfson Microelectronics Plc Light source protection circuit
US7884557B2 (en) 2006-07-14 2011-02-08 Wolfson Microelectronics Plc Protection circuit and method
GB2440186B (en) * 2006-07-14 2011-05-18 Wolfson Microelectronics Plc Protection circuit and method
WO2009000325A1 (en) * 2007-06-26 2008-12-31 Osram Gesellschaft mit beschränkter Haftung Circuit for driving an electro-optical transducer

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Legal Events

Date Code Title Description
PS Patent sealed
435 Patent endorsed 'licences of right' on the date specified (sect. 35/1949)
PCNP Patent ceased through non-payment of renewal fee