GB1294887A - - Google Patents

Info

Publication number
GB1294887A
GB1294887A GB1294887DA GB1294887A GB 1294887 A GB1294887 A GB 1294887A GB 1294887D A GB1294887D A GB 1294887DA GB 1294887 A GB1294887 A GB 1294887A
Authority
GB
United Kingdom
Prior art keywords
diode
feeding
few milliseconds
relay
shorrock
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
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 filed Critical
Publication of GB1294887A publication Critical patent/GB1294887A/en
Expired legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/16—Actuation by interference with mechanical vibrations in air or other fluid
    • G08B13/1654—Actuation by interference with mechanical vibrations in air or other fluid using passive vibration detection systems
    • G08B13/1672—Actuation by interference with mechanical vibrations in air or other fluid using passive vibration detection systems using sonic detecting means, e.g. a microphone operating in the audio frequency range
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/02—Mechanical actuation
    • G08B13/04—Mechanical actuation by breaking of glass

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Burglar Alarm Systems (AREA)

Abstract

1294887 Burglar alarms SHORROCK DEVELOPMENTS Ltd 22 Oct 1970 [1 Dec 1969] 58490/69 Heading G4N A breaking glass detector comprises a microphone M feeding a transister amplifier TR1 ... TR4 having a pass band in the range 6-10 kHz and feeding a diode pump frequency to voltage converter comprising capacitors C7, C8, diode D2 and transistor TR5. Signals above a minimum frequency and lasting for more than a few milliseconds will charge C8 quicker than it can be discharged by R13, so that after a few milliseconds, TR6 will reduce its emitter potential below the breakdown voltage of Zener diode D6, thus turning off TR7 and releasing relay A which operates an alarm lamp L. C8 is rapidly discharged via D5 and relay A remains off until reset by key RE. Other circuits may be connected at B.
GB1294887D 1969-12-01 1969-12-01 Expired GB1294887A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB5849069 1969-12-01

Publications (1)

Publication Number Publication Date
GB1294887A true GB1294887A (en) 1972-11-01

Family

ID=10481751

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1294887D Expired GB1294887A (en) 1969-12-01 1969-12-01

Country Status (1)

Country Link
GB (1) GB1294887A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2459489A2 (en) * 1979-06-21 1981-01-09 Jep Et Carre Electronic evaluation circuit for ultrasonic movement detector - uses Doppler-Fizeam effect and has high gain transistor amplifiers

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2459489A2 (en) * 1979-06-21 1981-01-09 Jep Et Carre Electronic evaluation circuit for ultrasonic movement detector - uses Doppler-Fizeam effect and has high gain transistor amplifiers

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Legal Events

Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee