| 摘要 |
An alarm clock has a housing provided with a control door having a permanent magnet and an actuating rod capable of pushing a conductive elastic piece located in the housing. The conductive elastic piece is capable of actuating a magnetic sensor which is located in the housing and is composed of an electromagnet and a relay capable of altering the polarity of the electromagnet to attract the permanent magnet of the control door. The magnetic sensor is actuated by the control circuit of the alarm clock at a desired time set to buzz such that the polarity of the electromagnet is changed by the relay, and that the control door is thus repelled to remain open.
|
