What is the alarm?
The alarm clock is a clock with a device. It can indicate the time and can send an audible signal or another signal at the time when people order. The movement structure of the alarm clock is mainly composed of mechanical and quartz electronic. Other types such as transistor balance springs, tuning forks and the like have been rarely used, usually called desktop alarms used on the table, mainly used for traveling travel alarm clocks. The travel time error of the daily mechanical alarm clock is generally within 120 seconds/day, and the travel time error of the quartz electronic alarm clock is generally within 0.2 second/day.
There are many kinds of alarm clocks, mechanical and quartz. Since it was invented by the principle of the pendulum, it has become an indispensable item in people’s lives.
How to choose an alarm clock
(1) Check the appearance first: the color of the bell shell is even and bright, without stripping, discoloration and scratches. The clock face should be clean, the scale is even, and the writing is clear.
(2) Check sensitivity: When the spring is slightly activated, the second-hand starts to move, which proves that the sensitivity is high. The clock with high sensitivity continues to take longer.
(3) Check the sound of walking time: Place the clock face left and right, up and down, if the sound is light and heavy in all directions, even if there is no noise, it means normal.
(4) Check whether the needle is touched: when the needle is moved, the minute hand is used, and the hour and minute hands are coincident with the second hand (the three needles overlap), and a certain gap should be maintained between the three needles, and it is not allowed to rub. At the same time, the needle and the clock face, the glass should also have a proper gap.
(5) Check the trouble: respectively, dial the noisy face to 3, 6, 9, 12, and then dial the hour and minute hand to these places. If the noise is within 5 minutes, the accident is normal.
(6) Check the alarm sound; the alarm sound should be clear, loud, no dumb, no air.
(7) Check the tightness of the needle spoon and the key spoon: the tightness should be moderate. If the needle is loose, it means that the spring force on the center wheel is insufficient, which will cause the second hand to go and the minute hand does not go or go slowly. If the key is loose, the alarm surface will follow the hour and minute hands. But if they are too tight, it is not convenient to use.