Note:①：回路是一个闭合的路径，它是从一个节点开 始，经过若干节点，再回到起始节点，任意一个节点只经 过一次。
A loop is said to be （可认为是）independent if it contains a branch which is not in any other loop.
The two circuits in Fig.1.1 and Fig.1.2 are identical.
However, for the sake of clarity②, nodes b and c are spread out ③with perfect conductors as in Fig.1.2.
Notice that the three points that form node b ① are connected by perfectly conducting wires and therefore constitute a single point.
Note:① "three points that form node b "表示"形成节点
Two or more elements are in series （串联）if they are cascaded or connected sequentially （接顺序连接）and consequently carry the same current（流过相同电流）.
Two or more elements are in parallel （并联）if they are connected to the same two nodes and consequently
abca ，意为包含2Ω电阻的闭合路径abca。
1.1 Introduction to Circuit Theory text
As the next two definitions show, circuit topology is of great value （=is very valuable）to the study of voltages and currents in an electric circuit.
Independent loops or paths result in（ 导致,结果是）
independent sets of equations.
1.1 Introduction to Circuit Theory text
For example, the closed path abca containing the 2Ω resistor ① in Fig.1.2 is a loop. Another loop is the closed istor and the current source. Although one can identify six loops in Fig.1.2, only three of them are independent.
电气工程及其自动化专业英语
主编 杨勇 邓秋玲
CONTENTS
Unit 1 Fundamentals of Electronic Circuits Unit 2 Power Electronics Unit 3 Electrical Machines Unit 4 Electric Power Systems Unit 5 Electric Power Generations Unit 6 Automatic Control Unit 7 Sensoring Technology Unit 8 Computer Network and Networked Control Unit 9 Signal Processing
Unit 1 Fundamentals of Electronic Circuits
1.1 Introduction to Circuit Theory 1.2 Analog and Digital Circuits 1.3 Three-Phase Circuits 1.4 Further Reading
A node is the point of connection between two or more branches.
1.1 Introduction to Circuit Theory text
A node is usually indicated by a dot in a circuit. If a short circuit (a connecting wire) connects two nodes, the two nodes constitute a single node. The circuit in Fig.1.1 has three nodes a, b, and c.
A network with b branches, n nodes, and l independent loops will satisfy the fundamental theorem of network topology:
b = l + n-1 (1.1)
Note：①containing the 2Ω resistor 作定语修饰 closed path
elements or devices, whereas a circuit is a network
providing one or more closed paths③.
Note：②：regard … as表示“把…认为” NNoottee：：③①：：pdrioffveirdeintgiaotnee在o此r m处o为re动clo词se，d dpiaftfherse为ntiate nbeettwwoerekn的A后an置d 定B表语示。区分A和B；To differentiate between a circuit and a network是目的状语从句.
A branch represents a single element such as a voltage source or a resistor. In other words, a branch represents any two-terminal element. The circuit in Fig.1.1 has five branches, namely, the 10V voltage source, the 2A current source, and the three resistors.
n. 循环，回路; vt. 使成环；
n. 拓扑；布局；拓扑学 n. 构造；结构；配置；外形 n. 终点站；终端；接线端
1.1 Introduction to Circuit Theory
New Words and Expressions
resistor
n. [电]电阻器
independent adj. 独立自主的；不受约束的
voltage across them②. The 5Ω and 2Ω resistors are
series
n. 连续；系列；级数；串联
parallel
adj. 平行的；并联的 n. 平行线；平
行面；v. 相应；平行
impedance
n. [电]阻抗；全电阻；[物]阻抗
theorem
n. [数]定理；法则
1.1 Introduction to Circuit Theory text
(1) Nodes, Branches and Loops Since the elements of an electric circuit can be
The 2Ω resistor, the 3Ω resistor, and the current source are in parallel because they are connected to the same two nodes (b and c) and consequently have the same
1.1 Introduction to Circuit Theory
New Words and Expressions
element interconnect node branch loop topology configuration terminal
n. 成分；元件 vt. 使互相连接
n. 节点 n. 分枝；分部；支流 v. 出现分歧
A loop is any closed path in a circuit. A loop is a closed path formed by starting at a node, passing through a set of nodes, and returning to the starting node without passing through any node more than once①.
1.1 Introduction to Circuit Theory text
In network topology, we study the properties relating to (关于...的特性)the placement of elements in the network and the geometric configuration of the network. Such elements include branches, nodes, and loops.
have the same voltage across them①.
Note:①：voltage across them表示关于两节点之间的电压， “them”指代“two nodes ”。
1.1 Introduction to Circuit Theory text