FR2430049A1 - Fire detector responsive to rate of temp. rise - has transistor base coupled to two identical thermistors forming voltage divider - Google Patents

Fire detector responsive to rate of temp. rise - has transistor base coupled to two identical thermistors forming voltage divider

Info

Publication number
FR2430049A1
FR2430049A1 FR7819571A FR7819571A FR2430049A1 FR 2430049 A1 FR2430049 A1 FR 2430049A1 FR 7819571 A FR7819571 A FR 7819571A FR 7819571 A FR7819571 A FR 7819571A FR 2430049 A1 FR2430049 A1 FR 2430049A1
Authority
FR
France
Prior art keywords
voltage divider
temp
fire detector
rise
transistor base
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.)
Withdrawn
Application number
FR7819571A
Other languages
French (fr)
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.)
COFFIN PIERRE
Original Assignee
COFFIN PIERRE
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 COFFIN PIERRE filed Critical COFFIN PIERRE
Priority to FR7819571A priority Critical patent/FR2430049A1/en
Publication of FR2430049A1 publication Critical patent/FR2430049A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B17/00—Fire alarms; Alarms responsive to explosion
    • G08B17/06—Electric actuation of the alarm, e.g. using a thermally-operated switch

Landscapes

  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Fire-Detection Mechanisms (AREA)

Abstract

The fire detector uses a thyristor (10) which is held in the blocked state by the saturation conduction of a transistor (6) connected its cathode and trigger electrodes. The transistor base is coupled via a capacitor (5) to a voltage divider provided by two identical thermistors (1, 2) one responsive to the ambient air temp. and one being thermally insulated to act as a reference. The potential at the centre of the voltage divider drops in response to a rapid temp. variation, causing the capacitor (5) to partially discharge, so that the transistor (6) drops below the threshold level, with the collector voltage then being sufficient to fire the thyristor (10) for energising a warning lamp (8).
FR7819571A 1978-06-30 1978-06-30 Fire detector responsive to rate of temp. rise - has transistor base coupled to two identical thermistors forming voltage divider Withdrawn FR2430049A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
FR7819571A FR2430049A1 (en) 1978-06-30 1978-06-30 Fire detector responsive to rate of temp. rise - has transistor base coupled to two identical thermistors forming voltage divider

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7819571A FR2430049A1 (en) 1978-06-30 1978-06-30 Fire detector responsive to rate of temp. rise - has transistor base coupled to two identical thermistors forming voltage divider

Publications (1)

Publication Number Publication Date
FR2430049A1 true FR2430049A1 (en) 1980-01-25

Family

ID=9210168

Family Applications (1)

Application Number Title Priority Date Filing Date
FR7819571A Withdrawn FR2430049A1 (en) 1978-06-30 1978-06-30 Fire detector responsive to rate of temp. rise - has transistor base coupled to two identical thermistors forming voltage divider

Country Status (1)

Country Link
FR (1) FR2430049A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5103916A (en) * 1990-07-02 1992-04-14 Fike Corporation Differential fire and explosion protection system
WO1997004429A1 (en) * 1995-07-21 1997-02-06 Thorn Security Limited Smoke detector labyrinth

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5103916A (en) * 1990-07-02 1992-04-14 Fike Corporation Differential fire and explosion protection system
WO1997004429A1 (en) * 1995-07-21 1997-02-06 Thorn Security Limited Smoke detector labyrinth

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Legal Events

Date Code Title Description
ST Notification of lapse