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Mechanical stopwatch use and maintenance precautions

The general use of a mechanical stopwatch is as follows：
(1) Before using the stopwatch, check the tightness of the clockwork. If the clockwork is already slack, you should turn the button on the top of the stopwatch to tighten the clockwork, but it should not be too tight.
(2) When measuring, press the button, the needle starts to move; press the button again, the needle stops moving; press the button a second time, the needle will return to the zero position.
When using the stopwatch, you should pay attention to holding it gently and avoid vibration and shaking as much as possible. When the needle is not zero, you should write down the zero reading, and then correct the reading after timing.

Maintenance Precautions：
1、Check the clockwork before using the stopwatch, if it is slack, tighten the clockwork, the clockwork should not be too tight, the general twist 13 or 14 times can be, do not over-tighten to avoid damage to the clockwork.
2、The use of the process should be gently held and put do not vibrate and shake, pay special attention to prevent the fall touch the stopwatch.
3、Do not use excessive force when pressing the meter to prevent damage to the unit.
4、After returning to the meter, if the stopwatch is not zeroed, its value (zero reading) should be noted and subtracted from the measured value after the experiment.
5、When not in use, the stopwatch should be turned on, relax the clockwork, and place the watch in a cool, dry place that is shockproof, rustproof and antimagnetic, and it is good to put the watch in the box.