JPS54161763A - Lamp filament snapping detection circuit - Google Patents

Lamp filament snapping detection circuit

Info

Publication number
JPS54161763A
JPS54161763A JP6996878A JP6996878A JPS54161763A JP S54161763 A JPS54161763 A JP S54161763A JP 6996878 A JP6996878 A JP 6996878A JP 6996878 A JP6996878 A JP 6996878A JP S54161763 A JPS54161763 A JP S54161763A
Authority
JP
Japan
Prior art keywords
lamp
filament
snapping
potential
turned
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
JP6996878A
Other languages
Japanese (ja)
Inventor
Takeshi Sakabe
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.)
NEC Corp
Original Assignee
NEC Corp
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 NEC Corp, Nippon Electric Co Ltd filed Critical NEC Corp
Priority to JP6996878A priority Critical patent/JPS54161763A/en
Publication of JPS54161763A publication Critical patent/JPS54161763A/en
Pending legal-status Critical Current

Links

Abstract

PURPOSE: To enable the immediate detection of filament snapping of a lamp through a simple construction, by connecting dummy diodes and a resistor to a no-lamp part of a lamp matrix, detecting the abnormal potential of a current circuit and turning on an indicator lamp.
CONSTITUTION: When an indicator 1 for indicating a turned-on lamp shows "0, 1, 1, 0", transistors Qb, Qf along axes X, Y are turned on through decoders 2a, 2b to supply an electrical current to the lamp LD22 connected at an intersection as to the axes X, Y to turn on the lamp. If the filament of the lamp snaps, the potential on the plus input of a sense amplifier 4 rises. Therefore, the potential is compared with a reference potential VREF. If the potential is higher than the reference potential, a lamp filament snapping flag 5 is set and a light emitting diode LDa for indicating the snapping of the lamp filament is turned on by a driver 6. A series circuit consisting of the dummy diodes D11, D43, D44 and the resistor r is coupled to each intersection with no lamp to distinguish between the filament snapping of the lamp and its absence.
COPYRIGHT: (C)1979,JPO&Japio
JP6996878A 1978-06-10 1978-06-10 Lamp filament snapping detection circuit Pending JPS54161763A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP6996878A JPS54161763A (en) 1978-06-10 1978-06-10 Lamp filament snapping detection circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6996878A JPS54161763A (en) 1978-06-10 1978-06-10 Lamp filament snapping detection circuit

Publications (1)

Publication Number Publication Date
JPS54161763A true JPS54161763A (en) 1979-12-21

Family

ID=13417951

Family Applications (1)

Application Number Title Priority Date Filing Date
JP6996878A Pending JPS54161763A (en) 1978-06-10 1978-06-10 Lamp filament snapping detection circuit

Country Status (1)

Country Link
JP (1) JPS54161763A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5787094A (en) * 1980-09-17 1982-05-31 Aerospatiale Device for inspecting plural indicator lamps

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5787094A (en) * 1980-09-17 1982-05-31 Aerospatiale Device for inspecting plural indicator lamps

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