GB1009271A - Improvements in or relating to smoke detector circuits - Google Patents
Improvements in or relating to smoke detector circuitsInfo
- Publication number
- GB1009271A GB1009271A GB8549/63A GB854963A GB1009271A GB 1009271 A GB1009271 A GB 1009271A GB 8549/63 A GB8549/63 A GB 8549/63A GB 854963 A GB854963 A GB 854963A GB 1009271 A GB1009271 A GB 1009271A
- Authority
- GB
- United Kingdom
- Prior art keywords
- point
- transistor
- responsive
- source
- smoke
- 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
Links
Classifications
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B17/00—Fire alarms; Alarms responsive to explosion
- G08B17/10—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
- G08B17/11—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using an ionisation chamber for detecting smoke or gas
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/62—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode
Landscapes
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- General Physics & Mathematics (AREA)
- Physics & Mathematics (AREA)
- General Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Biochemistry (AREA)
- Electrochemistry (AREA)
- Health & Medical Sciences (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Fire-Detection Mechanisms (AREA)
Abstract
1,009,271. Semi-conductor circuit. ASSOCIATED FIRE ALARMS Ltd., and B.J.L. WHITE. March 2, 1964 [March 4, 1963], No. 8549/63, Heading H3T. [Also in Division G1] The voltage at a point 17 between an ionization gauge 10 responsive to the amount of smoke in the atmosphere, and a resistor 11, which may be a second ionization chamber closed to the atmosphere, is applied to the modulator of a field effect transistor 14 fed from an LT source 16, and when as a result of smoke the voltage drops below that at point 18 current through transistor 14 ceases and point 20 which is set to become positive with respect to point 19 eventually renders transistors TR1 and TR2 conductive, diode D3 making the arrangement bi-stable. The larger current drawn from the source by the transistors actuates a relay in the supply lead. Capacitor C ensures that transistor TR1 does not conduct immediately on reset. A number of such circuits may be connected to a single LT power source, and the relay may be responsive to the total current drawn. Transistor 14 may be coupled to point 17 by a capacitor to make the circuit responsive only to rapid changes. Component values are exemplified.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8549/63A GB1009271A (en) | 1963-03-04 | 1963-03-04 | Improvements in or relating to smoke detector circuits |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8549/63A GB1009271A (en) | 1963-03-04 | 1963-03-04 | Improvements in or relating to smoke detector circuits |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1009271A true GB1009271A (en) | 1965-11-10 |
Family
ID=9854595
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8549/63A Expired GB1009271A (en) | 1963-03-04 | 1963-03-04 | Improvements in or relating to smoke detector circuits |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB1009271A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3521263A (en) * | 1966-02-22 | 1970-07-21 | Cerberus Ag | Ionization fire alarm and improved method of detecting smoke and combustion aerosols |
| US3543056A (en) * | 1967-08-07 | 1970-11-24 | Johnson Service Co | Proximity detection system using field effect transistors |
| GB2138570A (en) * | 1983-04-19 | 1984-10-24 | Emi Ltd | Smoke detector |
| CN102426751A (en) * | 2011-08-26 | 2012-04-25 | 无锡蓝天电子有限公司 | Point-type photoelectric smoke detector |
-
1963
- 1963-03-04 GB GB8549/63A patent/GB1009271A/en not_active Expired
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3521263A (en) * | 1966-02-22 | 1970-07-21 | Cerberus Ag | Ionization fire alarm and improved method of detecting smoke and combustion aerosols |
| US3543056A (en) * | 1967-08-07 | 1970-11-24 | Johnson Service Co | Proximity detection system using field effect transistors |
| GB2138570A (en) * | 1983-04-19 | 1984-10-24 | Emi Ltd | Smoke detector |
| CN102426751A (en) * | 2011-08-26 | 2012-04-25 | 无锡蓝天电子有限公司 | Point-type photoelectric smoke detector |
| CN102426751B (en) * | 2011-08-26 | 2013-07-17 | 无锡蓝天电子有限公司 | Point-type photoelectric smoke detector |
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