[VIP专享]yu 专英翻译段落

Electric charge is as fundamental a constituent of our Universe as the mass and energy. Indeed, present physical theory supposes that all matter consists of particles, the principal attributes of which are mass and electric charge

电荷是我们的宇宙的一个基本要素就像质量和能量。确实，目前的物理理论假设，所有的物质粒子组成，其中的主要属性是质量和电荷。

Two kinds of charge are known, arbitrarily designated positive and negative, which are characterized by the experimental observation that, under static conditions, separated like charges exert a mutual force of repulsion , whilst unlike charges ,under similar conditions ,exert a force of attraction .Under these conditions the field of force associated with charge is referred to as an electric field

两种已知的，被任意指定为正和负的电荷，通过实验观察表现出的特征是，它们在静态条件下，分开的同类电荷受到一个相互排斥的作用力，同时，不同类的电荷，在相同条件下，受到一个吸引的作用力。在这种情况下，与电荷有关的力场被称为电场。

The voltage source maintains a constant terminal voltage irrespective of the current supplied to the load. It is important to appreciate that the voltage may be a function of, for example, time, temperature, pressure, etc. it is constant only with respect to variations of load.

电压源的端电压保持恒定的，不论对当前提供给负载。重要的是要明白，电压可能是一个函数关于，例如，时间，温度，压力等，它是恒定的只考虑负载的变化。

The current source maintains a constant current in the load irrespective of the terminal voltage-which, in this case, is determined by the magnitude of the load. As with the voltage source, the generated current may depend on many other factors, but its one essential attribute is its independence of load.

电流源保持恒定的电流在负载里，不论末端电压如何，既然这样，是由负载的大小决定的。与电压源一样，生成的电流可能取决于其他许多因素，但其本质属性是它独立负载。

A circuit which is able to store electrostatic field energy is said to possess capacitance. The

property is defined in terms of the electric charge stored per unit of potential difference at its terminals, according to the equation: q(t)=Cv(t), where C is the capacitance, the units of which are FARADS when v and q are in volts and coulombs, respectively. Hence, a capacitance of 1 F stores a charge of 1C for a terminal p. d. of 1V. Combining equations gives: I(t)=C dv(t)/dt with t in seconds.

Thus, a current of 1A flows into a capacitance of 1 F when the terminal voltage changes at the rate of 1V/sec.

一个电路能够存储静电场能量，就是说拥有电容。他的性质被定义为根据两端电位差为1V时所储存的电量，根据公式：q(t)= Cv(t)，其中C是电容,单位是法拉，电压和电荷的单位分别是伏特和库仑。因此，1 F 的电容储存 1C的电荷为末端提供的电压是1V。结合等式为：I(t)=C dv(t)/dt，…

因此，当电压变化速率为每秒1V时，电容为1F，流入电容的电流为1A。As the temperature difference between the two junctions varies, the magnitude of the voltage

across the thermocouple pair also varies. The voltage thus provides an analog representation of the temperature difference. The other kind of signal is a digital signal. A digital signal is one that can take on values within two discrete ranges. Such signals are used to represent ON-OFF or YES-NO information

An ordinary household thermostat delivers a digital signal to control the furnace. When the room temperature drops below a preset value, the thermostat switch closes turning ON the furnace. Once the room temperature rises high enough, the switch opens turning OFF the furnace. The current through the switch provides a digital representation variation: On equals “too cold” while OFF equals “not too cold ”.

由于两个节点间的温度差不同，热电偶的电压大小也不同。电压因此提供一个模拟（信号）代表温度差。另一种信号是数字信号。一个数字信号是可以在两个离散范围里取值的。这样的信号被用于代表开-关或是-非的信息。

一个普通家用自动调温器传送一个数字信号去控制火炉，当室内温度下降到低于一个预设值，自动调温器开关闭合打开炉子。当室内温度上升到足够高，开关打开关闭炉子。流过按钮的电流提供一个数字代表变量：ON等于“太冷”当OFF等于“不太冷”。Our present system of number has 10 separate symbols 0,1,2,3,…..9，which are called Arabic numerals. We would be forced to stop at 9 or to invent more symbols if it were not for the use of positional notation. An example of earlier types of notation can be found in Roman numeral, which are essentially additive: III=I+I+I, XXV=X+X+V. New symbols (X,C,M, etc.) were used as the numbers increased in value. Thus V rather than IIIII=5. The only importance of position in Roman numerals lies in whether a system precedes or follows another symbol (IV=4), while (VI=6).

The clumsiness of this system can easily be seen if we try to multiply XII by XIV. Calculating with Roman numerals was so difficult that early mathematicians were forced to perform arithmetic operations almost entirely on abaci, or counting boards, translating their results back into Roman-number form. Pencil-and-paper computations are unbelievably intricate and difficult in such systems. In fact, the ability to perform such operations as addition and multiplication was considered a great accomplishment in earlier civilization.

我们现在的数制有10个单独的符号0,1,2,3,...,9，这被称为阿拉伯数字。我们将被迫停止在9或发明更多的符号，如果它不供位置计数法使用。一个较早的符号类型的例子可以发现在罗马数字，是本质上加法的：III=I+I+I（3=1+1+1），XXV=X+X+V（25=10+10+5）。新的符号（X，C，M等）被用来做数值的增加。因此，V，而不是IIIII=5。唯一位置的重要性在罗马数字在于能否超前系统或在一个符号之后（IV= 4），而（VI= 6）。

当我们试着12乘以14，这个系统的笨拙显而易见。用罗马数字计算很困难，以至于早期数学家被迫演示算术运算几乎完全在算盘或计数板上，再将结果转换回罗马数字形式。这种系统中，纸笔计算是难以置信的复杂和困难。事实上，有能力去演算加法和乘法运算是被认为一个伟大的成就在早期文明中。

The base, or radix of a number system is defined as the number of different digits which can occur in each position in the number system. The decimal number system has a base, or radix, of 10. This means that the system has 10 different digits (0,1,2,…9)any one of which may be used in each position is a number.

History records the use of several other number systems. The quinary system, which has 5 for its

base, was prevalent among Eskimos and North American Indians. Examples of the duodecimal system (base 12) may be seen in clocks, inches and feet and in dozens or grosses.

这个基础，或一个数字系统的基数被定义为是不同的数字，可以出现在数字系统的任何位置。十进制数字系统有一个基础，或基数，10。这意味着系统有10个不同的数字（0,1,2，... 9）其中任何一个可以用于每个位置上是一个数字。

历史记录了几个其他数字系统的使用。五进制，基数为5，流行于爱斯基摩人和北美印第安人中。十二进制（基数12）的例子，可看到在钟表，英寸，英尺，在打或总数。The section is concerned with digital system variables that take on only two values (binary variables). We conventionally denote these values as “0”and”1”,and then use a special set of rules called Boolean algebra to summarize the various ways in which digital variables can be combined. This algebra and much of the notation are adopted directly from mathematical logic. Thus, “logic variable ” or“logic operation” are commonly used in place of “digital variable” or “digital operation”.

本节讨论关于只取两个数值的数字系统变量（二进制变量）。我们习惯上用“0”或“1”表示，然后用一套特殊的规则被称为布尔代数来总结数字变量的各种组合方式。这个代数和符号直接从数理逻辑被采用。因此，“逻辑变量”或“逻辑运算”是常用于代替“数字变量”或“数字经营”。

The principal importance of NOR and NAND is that they are the simplest logic functions to construct in integrated circuit form. Thus, while it may be easier for the beginner to learn to “think” with OR and AND , he should also practice thinking with NOR and NAND as these functions are likely to be used in the final circuit realization. Also, it is possible to synthesize all of the logic functions using only NOR gates or only NAND gates .

与非门和或非门主要的重要性是他们最简单的逻辑功能构建集成电路形式。因此，虽然用或门和与门可能会更容易为初学者学习思考，但他应该也练习用与非门和或非门思考，因为这些功能有可能用于最终电路的实现。另外，它可能合成所有逻辑功能只用与非门和或非门。

Let us formulate a simple everyday situation in terms of digital variables and Boolean operations. Suppose you are driving home and become thirsty for a hot drink. You see a diner ahead and pull in . Let us develop a Boolean equation for whether or not you obtain a drink.

让我们阐述数字变量和布尔操作方面简单的日常生活情况。假设你开车回家，并变得口渴想要一杯热饮。您看到一个小餐馆在前面，靠边停下。让我们制定一个你是否取得喝布尔方程。

The final step is to construct a logic flow diagram using gate symbols. Two possible logic flow diagrams, corresponding to Eq.5.16 and Eq.5.17 are shown in Figure 5.5. As an illustration of how only NOR gates or only NAND gates can be used to synthesize any function, two additional implementation of this same example are shown in Figure 5.6. Notice that when both inputs of the two-input NOR gate are connected together ,as in Figure 5.6(a), the gate becomes an inverter.最后一步是用门符号构建一个逻辑流程图，两种可能的逻辑流程图，对应于公式5.16和公式5.17如图5.5所示。作为一个例证说明如何只有或非门或与非门可以用来合成人一个功

能，两个附加的执行这一相同的示例如图5.6所示。注意当或非门的两个输入端输入连在一起，如图5.6(a)所示，这个门变成了一个反相器。

The last case to consider is SET=CLEAR=1.This condition will produce 0 at the output of both NOR gates, so Q=0 and /Q=0. This is obviously an illegal condition if it is desired that the FF outputs be the inverse of each other. Furthermore, when the inputs are returned to 0, the FF output state will depend on which input reaches 0 first. This makes the SET=CLEAR=1 condition ambiguous. For these reasons the latter case is never purposely used during the operation of this type of FF.

最后的情况要考虑的是设置=清除=1，这种情况会产生0在或非门的两个输出端，所以Q=0和/Q=0。这明显是一个非法的条件如果它希望触发器的输出是互逆的。此外，当输入恢复到0，触发器输出门将决定于哪个输入先到达0。这使设置=清除=1条件不明确。由于这些原因后面的情况是绝不会故意的使用在这类型的触发器的操作中。

The clock signal is the signal that causes things to happen at regularly spaced intervals. In particular, operations in the system are made to take place at times when the clock signal is making a transition from 0 to 1 or from 1 to 0. These transition times are pointed out in the figure. The 0-to-1 transition is called the rising edge or positive-going edge of the clock signal; the 1-to-0 transition is called the falling edge or negative-going edge of the clock signal.

时钟信号是使事情发生在规律的时间间隔的信号。特别是，系统中的运行发生变化,当时钟信号从0到1，或者从1到0时。这些转换时间再图中被指出。0到1的转变被称为上升沿时钟信号，1到0的转变称为下降沿时钟信号。

The following Figure5.12 shows the symbol for a clocked S-C flip-flop that triggers on the negative-going transition at its CLK input. The small circuit and triangle on the CLK input indicates that this FF will trigger only when the CLK input goes from 1 to 0.

This FF operates in the same manner as the positive-edge FF of the above figure except that the output can change states only on the falling edge of the clock pulses (points b,d,f,h,and j). Both positive-edge and negative edge triggering FFs are used in digital system.

下面的图5.12显示了给CLK输入端一个下降沿的触发信号，时钟S-C触发器的符号转变。CLK输入信号端的小圆圈和三角形表明，只有在CLK输入信号从1变为0时，触发器才会触发。上升沿触发的触发器一样，和这种触发器以同一种方式运行，除了输出只有在时钟脉冲的下降沿时，才会改变状态。上升沿和下降沿触发的触发器都被用于数字系统

Because an op-amp has several terminals, we must define voltage and current variables in a way

that avoids confusion and aids in the visualization of network behavior. The use of a reference node greatly simplifies the notational problems (Figure 5.14).

If we wish to compare the height of two persons, we stand them up on a flat surface (the reference level) and see which one is taller. Similarly, if we wish to determine the potential difference between two points, we can measure the potential difference from each point to a reference node, then subtract one from the other.

因为运算放大器有几个端点，为了避免混淆和帮助观察网络行为可视化，我们必须定义电压和电流的变量。参考节点的使用极大的简化了符号问题。如果我们想去比较两个人得高

度，我们让他们站在一个水平的平面上，看哪一个更高点。同样的，如果我们希望确定两点间的电位差，我们可以测量出每一点到参考节点的电位差，然后减去另外一个到参考节点的。

The complete symbol for the op-amp with the reference node and both supply batteries in place is show in Figure5.16(a). The symbols VCC is often used for the supply voltage, a carry-over from conventional transistor-circuit notation. The positive and negative supplies are shown as having equal magnitudes.

Although this is the most common arrangement it is not a necessary arrangement. Most op-amps operate with a wide range of supply voltages, and these voltages need not be symmetrical about the ground. Information about the choice of supply voltage and the corresponding limitations on inputs and outputs is usually provided on the op-amp data sheet.

In Figure 5.16(a). The input voltage V- and V+, are ordinary network variables and, as such, might be either positive or negative. The subscript is associated with the name of the input terminal, not with the algebraic sign of the voltage.

带有参考节点和双电池电源的运算放大器的完整符号如图5.16(a)所示，习惯上用符号VCC表示电源电压，一个模仿传统的晶体管电路符号。正负极电压显示有相等的大小。虽然这是最常见的做法，但不是必要的。多数运放工作在大范围的电源电压，这些电压不必关于地面对称。电源电压和相应限制输入和输出的选择信息，通常是运算放大器上提供数据表。在图5.16（a）中，输入电压V- 和V+是根据普通网络变量，同样的，可能是正极或负极。下标与输入端有关，与电压正负极符号无关。

Two shorthand notations for op-amps are shown in Figure 5.16(b)and 5.16(c). In Figure5.16(b), the reference node is presumed; proper connections to supplies are presumed, and inputs and outputs are labeled with the appropriate node-to-reference voltages. Often the supply, terminals are left off, as in Figure 5.16(c). However, this streamlined notation can be confusing, as explained below.

运算放大器的两个简化符号表示如图5.16（b）和5.16（c）。在图5.16（b）中，参考节点是假定的；电源的适当连接也是假定的，而且输出输入均用节点到参考节点电压标志。通常电源端，末端的被省略，如图5.16（c）一样会停止。然而，这些合理的符号的可能令人迷惑，正如下面解释