[关于《信号完整性和印制电路板》一书的疑问
时间：10-02
整理：3721RD
点击：
信号完整性和印制电路板一书的第三章中，讲到电容的时候，有如下的叙述：
Another way to think about this is to recognize how many electrons actually flow during a half-cycle of an AC current. A 1-MHz waveform changes direction 106 times each second. Therefore, for the same magnitude of peak current (charge/unit time), only one-millionth (10–6) as many electrons flow during the half-cycle of a 1-MHz (106) waveform as flow during the half-cycle of a 1-Hz waveform. Therefore, the voltage buildup on a capacitor will be substantially less for a half-waveform of a 1-MHz signal than for a 1-Hz signal. 6_Signal.Integrity.Issues.And.Printed.Circuit.Board.Design.chm::/013141884X_ch03lev1sec4.html#ch03table01]Table 3-1 summarizes the range of possibilities.
Table 3-1. Capacitor size and frequency both affect the flow of current.[img=401,111]mkMSITStore:G:\ebook\circuit\信号完整性和印制电路板设计\[D.Brooks]6_Signal.Integrity.Issues.And.Printed.Circuit.Board.Design.chm::/FILES/45fig01.gif[/img]
中文如下： [img=925,311]file:///C:/DOCUME~1/THINKP~1/LOCALS~1/Temp/42$AS%7DA03]P)U[TYRG@D8G7.jpg[/img]
Another way to think about this is to recognize how many electrons actually flow during a half-cycle of an AC current. A 1-MHz waveform changes direction 106 times each second. Therefore, for the same magnitude of peak current (charge/unit time), only one-millionth (10–6) as many electrons flow during the half-cycle of a 1-MHz (106) waveform as flow during the half-cycle of a 1-Hz waveform. Therefore, the voltage buildup on a capacitor will be substantially less for a half-waveform of a 1-MHz signal than for a 1-Hz signal. 6_Signal.Integrity.Issues.And.Printed.Circuit.Board.Design.chm::/013141884X_ch03lev1sec4.html#ch03table01]Table 3-1 summarizes the range of possibilities.
Table 3-1. Capacitor size and frequency both affect the flow of current.[img=401,111]mkMSITStore:G:\ebook\circuit\信号完整性和印制电路板设计\[D.Brooks]6_Signal.Integrity.Issues.And.Printed.Circuit.Board.Design.chm::/FILES/45fig01.gif[/img]
中文如下： [img=925,311]file:///C:/DOCUME~1/THINKP~1/LOCALS~1/Temp/42$AS%7DA03]P)U[TYRG@D8G7.jpg[/img]
续
看图片英文和中文的都有。
续
中文的，有点模糊
续
文中提到，半个周期内的同幅度的电流信号，一个1MHz,一个1Hz，1Hz的电流信号流过的电子要多一些。
另外，根据上面显示的表格，1MHz比1Hz的频率要大，所以1MHz的float of current要多一些。
上面两句话，第一句说的是半周期内的电子数量，第二句说的是float of current。搞得我有点懵。
分开理解都是很好理解的，比如第一句话，半周期的电子数量不就是电量?因为1Hz对应的周期要长于1MHz，而在幅值相同的时候（即直流等效值也一样），所以当然是1Hz的电子数量要多一些。
而第二句话，“1MHz的float of current要多一些”，首先，我对float of current的理解就是电流的大小也可以说是电流的流量。因为此段文章的上下文说的是电容，所以结合电容来说，隔直通交，通高阻低，那么1MHz的电流肯定比1Hz的要大。
但是，总感觉这两点放在一起好像没什么关联，甚至很容易让人头大想晕。
其实这个问题也是挺无聊的，只希望有看过这本书的朋友，可以说一说这两句话有任何一点的联系吗?
學習中
3q3q
push~