电火花计时器较电磁打点计时器具有使用方便、纸带运动时阻力小、实验误差小等优点,可如何把它固定在铁架台上,却令人颇费一番周折。如在“验证机械能守恒定律”实验中,书上的方法是用铁夹固定(见图1),穿纸带的一端总是往下垮;用白铁皮在电火花计时器周身箍一圈,再用螺丝把白铁皮与铁棍连接起来,以便于固定到铁架台上(见图2),可是,把计时器平放在轨道小车上时必 The EDM timer has the advantages of easy use of electromagnetic timing timer, small resistance when the tape is moving, and small experimental error. How to fix it on the iron stand can be quite complicated. For example, in the “Verification of the conservation of mechanical energy” experiment, the method in the book is fixed with iron clips (see Figure 1). One end of the paper tape is always squatting down; and the circumference of the EDM timer is hoop with a tin plate. Then use a screw to connect the tin plate with the iron bar so that it can be fixed to the iron stand (see Figure 2). However, when the timer is placed flat on the trolley, it must be