| 摘要 |
An alarm system attached to an electronic or electrical device is triggered by unplugging or removing AC power cord. The circuit of said alarm system is monitoring the presence of AC voltage. If it finds the absence of the AC source, then said alarm is activated. Included in the alarm system is a timer circuit, which stops the alarm sounding after certain period of time that is adjustable. An LED is indicating that said alarm is armed. The alarm system is designed such a way that it consumes very little current during a quiescent state to save the battery usage. Said alarm system is battery powered for it's own circuit. The power supply circuit generates DC voltage for the purpose of checking AC voltage connection to the power line.
|
