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Showing posts with the label ALARM CIRCUITS

3v Sweeping Siren Alarm

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The circuit uses a LTC1799 precision frequency generator from Linear Technology.  A 74HC14 hex Schmitt trigger from Texas Instruments is also used to perform several other functions.  One section is wired as a simple 7Hz square wave oscillator.

Low Voltage 120vac Power Line Alarm

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This circuit will turn on a beeper when the line voltage drops below 100 volt AC.