电气工程及其自动化专业英语课文翻译.docVIP

第一章第一篇sectiong Two variables u(t) and i(t) are the most basic concepts in an electric circuit, they characterize the various relationships in an electric circuit u(t)和i(t)这两个变量是电路中最基本的两个变量，它们刻划了电路的各种关系。 Charge and Current The concept of electric charge is the underlying principle for explaining all electrical phenomena. Also, the most basic quantity in an electric circuit is the electric charge. Charge is an electrical property of the atomic particles of which matter consists, measured in coulombs (C). 电荷和电流 电荷的概念是用来解释所有电气现象的基本概念。也即，电路中最基本的量是电荷。电荷是构成物质的原子微粒的电气属性，它是以库仑为单位来度量的。 We know from elementary physics that all matter is made of fundamental building blocks known as atoms and that each atom consists of electrons, protons, and neutrons. We also know that the charge e on an electron is negative and equal in magnitude to 1.60210×10-19C, while a proton carries a positive charge of the same magnitude as the electron. The presence of equal numbers of protons and electrons leaves an atom neutrally charged. 我们从基础物理得知一切物质是由被称为原子的基本构造部分组成的，并且每个原子是由电子，质子和中子组成的。我们还知道电子的电量是负的并且在数值上等于1.602100×10-12C，而质子所带的正电量在数值上与电子相等。质子和电子数量相同使得原子呈现电中性。 We consider the flow of electric charges. A unique feature of electric charge or electricity is the fact that it is mobile; that is, it can be transferred from one place to another, where it can be converted to another form of energy 让我们来考虑一下电荷的流动。电荷或电的特性是其运动的特性，也就是，它可以从一个地方被移送到另一个地方，在此它可以被转换成另外一种形式的能量。 When a conducting wire is connected to a battery (a source of electromotive force), the charges are compelled to move; positive charges move in one direction while negative charges move in the opposite direction. This motion of charges creates electric current. It is conventional to take the currentflow as the movement of positive charges, that is, opposite to the flow of negative charges, as Fig.l-1 illustrates. This convention was introduced by Benjamin Franklin (l706～l790), the American scientist and inventor. Although we