Telephone alarm without external power

The utility model relates to a telephone alarm without external power. The utility model is characterized in that polarity switching circuits D1-D4 are divided into three ways to be respectively connected with a off-hook switch 4 and pressure reducing circuits 1 and 2; a circuit 1 is connected with...

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Bibliographic Details
Main Author WANGUO DU
Format Patent
LanguageEnglish
Published 14.10.1998
Edition6
Subjects
ALARM SYSTEMS
ELECTRIC COMMUNICATION TECHNIQUE
ELECTRICITY
ORDER TELEGRAPHS
PHYSICS
SIGNALLING
SIGNALLING OR CALLING SYSTEMS
TELEPHONIC COMMUNICATION
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Summary:The utility model relates to a telephone alarm without external power. The utility model is characterized in that polarity switching circuits D1-D4 are divided into three ways to be respectively connected with a off-hook switch 4 and pressure reducing circuits 1 and 2; a circuit 1 is connected with a dial circuit 3; a circuit 2 is connected with a triggering and self-locking circuit 6; lead-out wires 15 of the A end and the b end of an alarm 10 are connected with a telephone wire in parallel. The utility model has the advantages that the power supply of the telephone wire is used; the utility model is corresponding to normal telephone dialing at the time of work; current is almost zero at the time of static waiting; the telephone alarm without external power can be used as a corresponding alarm by matching with the other sensors; the size of the device is small; the power consumption is low; the cost is low; concealment can be easily implemented; one alarm can be provided with a plurality of trigger switches and sensors; the reliability is high.
Bibliography:Application Number: CN1997217371U