An alarm clock refers to a clock that can sound at a predetermined time.

The specific interpretation is as follows:

I. Citation and explanation

1 refers to a clock that can sound at a predetermined time.

2. Zhou Libo's "Hot Metal Rushing" III: "There is a never-noisy mouth in front of the mirror frame, and the short hand always points to five o'clock, which is the small alarm clock at the end of the factory." People's Literature 198 1 8: "I slept peacefully all night and was awakened by the alarm clock at the bedside.

Second, the alarm clock is a clock with an alarm device. It can not only indicate the time, but also send out sound signals or other signals according to people's predetermined time. The movement structure of alarm clock mainly includes mechanical type and Shi Ying electronic type. Other types, such as transistor balance spring and tuning fork, are rarely used. They are called desktop alarm clocks which are usually placed on the table, and travel alarm clocks which are mainly used for travel. The time error of daily mechanical alarm clock is generally within120s/day, while that of Shi Ying electronic alarm clock is generally within 0.2s/day.

There are many kinds of alarm clocks, mechanical and Shi Ying. Since it was invented by people using the principle of pendulum, it has become an indispensable item in people's lives.

Fourth, Zhou Libo's "Hot Metal Rushing" III: "There is a never-noisy mouth in front of the mirror frame, and the short hand always points to five o'clock, which is the small alarm clock at the end of the factory." People's Literature 198 1 No.8: "I slept peacefully all night and was awakened by the alarm clock at the bedside."