Glass breakage alarm for monitoring windows/display windows has temperature sensor that outputs alarm signal when temperature exceeds upper temperature threshold or falls below lower threshold

摘要

The alarm has a signal evaluation circuit connected to a mechanical-electrical converter, especially a sound-in-solid transducer, and at least one temperature sensor that produces an alarm signal when an upper temperature threshold is exceeded and when the temperature falls below a lower temp. threshold. The temperature sensor contains a PTC resistor (R8) and an NTC resistor (R13) in series connected to the control input of a transistor (V1) that triggers the alarm signal.