学习“带电粒子在匀强电场中的运动”时,有学生联系简谐运动的定义,问“示波器中在YY′偏转电极上加上电压 U=U_msinωt 时,光斑是做简谐运动吗?”我们来分析示波器中光斑的位移随时间的变化关系.示波器的核心部件是示波管,示波管的原理如图1所示,电子被加速后以初速度 v_0进入 When studying “the movement of charged particles in a uniform electric field”, the student has contacted the definition of simple harmonic motion and asked “when the voltage U=U_msinωt is applied to the deflection electrode of YY′ in the oscilloscope, is the spot doing simple harmonic motion?” We analyze the relationship of the displacement of the spot in the oscilloscope over time. The core component of the oscilloscope is the oscilloscope. The principle of the oscilloscope is shown in Figure 1. The electrons are accelerated and entered at the initial speed v_0.