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US 2004/0164872 A1Published application
Battery free audio door bell
OwnerChing-Huan Chiu, Tao-Hsi Chiinventors
Life of this patent
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Abstract
A battery free door bell includes a power supply unit connected to two limited-voltage wave-filtering circuit units for providing power to interior circuit and exterior circuit. The interior circuit has a steady voltage unit and a first amplifying circuit unit so as to provide a signal to a music IC unit. A second amplifying circuit unit is connected to a speaker. The exterior circuit has a switch unit, a delay circuit and a third amplifying circuit unit. A storage circuit unit is connected to the delay circuit unit. The third amplifying circuit unit continuously activates the music IC unit.
Claims2
A battery free door bell comprising:
- a power supply unit;
- two limited-voltage wave-filtering circuit units respectively connected to the power supply unit and providing electric power to an interior circuit and exterior circuit;
- the interior circuit having a steady voltage unit, a first amplifying circuit unit and providing a signal to a music IC unit, a second amplifying circuit unit connected to a speaker;
- the exterior circuit having a switch unit, a delay circuit and a third amplifying circuit unit, and
- a storage circuit unit connected to the delay circuit unit, the third amplifying circuit unit continuously activating the music IC unit.
2 more elements
Dependencies are inferred from the claim text.