| 摘要 |
An alarm device that connects to a circuit using two wires and is actuated when a switch changes the status of the circuit from a normally closed circuit condition to open circuit condition. The alarm device includes a PC board with an electronic buzzer, an electronic signal transmitter and/or a visual indicator, such as a flashing LED, all of which may be enclosed within a case. The circuitry of the alarm device is non-polarized, thereby allowing the two wires to be connected to either terminal connection point in the circuit.
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