EP 0130702 A1 19850109 - Alarm system.
Title (en)
Alarm system.
Title (de)
Alarmsystem.
Title (fr)
Système d'alarme.
Publication
Application
Priority
GB 8315110 A 19830602
Abstract (en)
An alarm system comprises an electrical resistance bridge circuit (R3, D5; R5; R6; R4, D6) in which a first arm (R5) of the bridge comprises a loop incorporating a number of resistive detector units whose resistance varies depending on its state. A second arm (R6) of the bridge comprises a potentiometer operable to balance the bridge. The circuit includes means (IC1, IC2) operable to produce an output signal in response to an imbalance of the bridge which results in a potential difference at the balance points (X, Y) which is greater than a pre-set, adjustable value, and which is used to initiate an alarm. This enables the sensitivity of the bridge circuit to be altered either manually or automatically, and is used to facilitate accurate balancing of the bridge which is required if the circuit is not to be prone to false alarm conditions.
IPC 1-7
IPC 8 full level
G08B 13/08 (2006.01); G08B 13/12 (2006.01)
CPC (source: EP)
G08B 13/08 (2013.01); G08B 13/126 (2013.01)
Citation (search report)
- [Y] FR 2390783 A1 19781208 - JEUMONT SCHNEIDER [FR]
- [Y] US 3825920 A 19740723 - NELSON R, et al
- [AD] GB 1429781 A 19760324 - CHILD J V
Designated contracting state (EPC)
AT BE CH DE FR GB IT LI LU NL SE
DOCDB simple family (publication)
DOCDB simple family (application)
EP 84303706 A 19840601