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在很多物理實驗中需要使用一種自动化的記時器,用它自动记錄短段的時間。在下面的情形,这种仪器尤其重要,就是需要研究高速度過程時,如自由落體、擺的振動、電动機軸的轉動等问题。 這樣的仪器在一般實驗參考書中的記載,多半都是在電動機的軸上固定一支毛筆,充作記時器,利用電動機電枢的等速旋轉,它軸上的毛筆便可以在相等的時間間隔碰到运动着的物体上,画出线来。如研究自由落體便是用这个方法。知道了电动机每分鐘的轉数,便可求出每轉的時間。但是这里必須指出要保持電动機轉数的均恒以及測量这个轉数,以學校的條件來說,是一件複雜的問題。過去曾應用带刻畫針的音叉作記時器,這個仪器的缺點是音叉振动是阻尼振动,很快就衰弱下去,同時還
In many physical experiments need to use an automatic timer, use it to automatically record the short period of time. In the following cases, this instrument is particularly important when it comes to researching problems such as free-fall, vibrations, motor shaft rotation, etc. at high speed. Such instruments in the general experimental reference book records, mostly in the motor shaft fixed a brush, as a chronograph, the use of motor armature constant rotation, the brush on its axis can be equal Time interval hit the moving object, draw the line. Such as the study of free fall is to use this method. Know the motor revolutions per minute, you can find the time for each turn. However, it must be pointed out here that maintaining the motor revolutions constant and measuring the number of revolutions is a complex issue for school conditions. In the past, the use of an engraved tuning fork as a chronograph has the disadvantage that the tuning fork vibration is a damped vibration and soon weakened,