| 摘要 |
The contactless siren of an automobile is embodied to generate an alarm sound with a uniform volume by using a contactless method, to thereby suppress an arc phenomenon caused upon a contact method. The contactless siren in an automobile horn having a lower frame(1) on which a bobbin(3) is installed and a vibration plate(5) forming a metal projected bar(8) on the center thereof, comprises a circuit substrate(7) installed on the outside of the bobbin(3) of the lower frame(1) and connected to a constant voltage circuit(10) comprised of a diode(D) and a regulator(IC1), an oscillating circuit(15) comprised of first and second integrated circuits(IC2,IC3), resistors(R1-R3) and condensers(C1-C4), and a switching circuit(20) comprised of a resistor(R4) and a transistor(T), respectively.
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