GB668374A - Improvements in or relating to electronic indicating or warning apparatus - Google Patents

Improvements in or relating to electronic indicating or warning apparatus

Info

Publication number
GB668374A
GB668374A GB28602/48A GB2860248A GB668374A GB 668374 A GB668374 A GB 668374A GB 28602/48 A GB28602/48 A GB 28602/48A GB 2860248 A GB2860248 A GB 2860248A GB 668374 A GB668374 A GB 668374A
Authority
GB
United Kingdom
Prior art keywords
valve
grid
indicating
voltage
nov
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
GB28602/48A
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Publication of GB668374A publication Critical patent/GB668374A/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
    • G08B13/22—Electrical actuation
    • G08B13/24—Electrical actuation by interference with electromagnetic field distribution
    • G08B13/2491—Intrusion detection systems, i.e. where the body of an intruder causes the interference with the electromagnetic field

Abstract

668,374. Indicating proximity of bodies. JOHANSSON, K. L. Nov. 3, 1948 [Nov. 12, 1947], No. 28602/48. Class 37. An electronic device for indicating the presence of a body comprises an oscillator valve F1 whose output is rectified and taken via a smoothing network R2, R3, C4, C5 to the control grid of an amplifying valve F2, containing a relay winding Re in the anode lead. The presence of a body near an aerial A damps the oscillator output and reduces the grid voltage of F2 to cause the anode current to rise and energize relay winding Re. Changes in the supply voltage are compensated in valve F2 by the neutralizing effects of the resulting changes in grid and anode voltage.
GB28602/48A 1947-11-12 1948-11-03 Improvements in or relating to electronic indicating or warning apparatus Expired GB668374A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE668374X 1947-11-12

Publications (1)

Publication Number Publication Date
GB668374A true GB668374A (en) 1952-03-19

Family

ID=20314536

Family Applications (1)

Application Number Title Priority Date Filing Date
GB28602/48A Expired GB668374A (en) 1947-11-12 1948-11-03 Improvements in or relating to electronic indicating or warning apparatus

Country Status (1)

Country Link
GB (1) GB668374A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3276005A (en) * 1964-05-05 1966-09-27 Mosler Res Products Inc Capacity intruder alarm having capacitive a.c. coupling and d.c. bias coupling in parallel between a detector and amplifier
US3333160A (en) * 1964-02-24 1967-07-25 Water Economy And Res Company Proximity responsive system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3333160A (en) * 1964-02-24 1967-07-25 Water Economy And Res Company Proximity responsive system
US3276005A (en) * 1964-05-05 1966-09-27 Mosler Res Products Inc Capacity intruder alarm having capacitive a.c. coupling and d.c. bias coupling in parallel between a detector and amplifier

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