In the case of a resistor, the voltage-current relationship is given by Ohm’s law, which states that the voltage across the resistor is equal to the current through the resistor multiplied by the value of the resistance.就电阻来说, 电压—电流的关系由欧姆定律决定。
欧姆定律指出:电阻两端的电压等于电阻上流过的电流乘以电阻值。
2]It may be that the inductor voltage rather than the current is the variable of interest in the circuit. 或许在电路中,人们感兴趣的变量是电感电压而不是电感电流。
Viewed in this light, it will be found that the analysis of three-phase circuits is little more difficult than that of single-phase circuits.这样看来,三相电路的分析比单相电路的分析难不了多少。
At unity power factor, the power in a single-phase circuit is zero twice each cycle.在功率因数为 1时,单相电路里的功率值每个周波有两次为零。
It should be noted that if the polarity of point Awith respect to N ( is assumed for the positive half-cycle, then when used in the same phasor diagram should be drawn opposite to, or 180? out of phase with, .应该注意,如果把 A 点相对于 N 的极性(定为正半周,那么在用于同一相量图中时就应该画得同相反,即相位差为 180?One problem with electronic devices corresponding to the generalized amplifiers is that the gains, AU or AI, depend upon internal properties of the two-port system.对应于像广义放大器这样的电子装置,一个问题就是增益 AU 或者 AI ,它们取决于两输入端系统的内部特性。
This is one of the key features of Op-Amp design— the action of the circuit on signals depends only upon the external elements which can be easily varied by the designer and which do not depend upon the detailed character of the Op-Amp itself.这是运算放大器设计的重要特征之一——在信号作用下, 电路的动作仅取决于能够容易被设计者改变的外部元件,而不取决于运算放大器本身的细节特性。
Put very simply a semiconductor material is one which can be “doped” to produce a predominance of electrons or mobile negative charges (N-type; or “holes” or positive charges (P-type.简单地说,半导体是这样一种物质,它能够通过“掺杂”来产生多余的电子,又称自由电子 (N 型 ;或者产生“空穴” ,又称正电子(P 型。
TO1 is the original transistor shape —a cylindrical “can” with the three leads emerging in triangular pattern from the bottom. Looking at the base, the upper lead in the “triangle” is the base, the one to the right (marked by a color spot the collector and the one to the left the emitter. TO1是最早的一种晶体管形状——即一个带有三个引脚的圆柱体“外罩” ,这三个引脚在底部形成三角状。
首先要注意的是, “三角形”上面的引脚是基极,其右面的引脚(由一个彩色点标出为集电极,其左面的引脚为发射极。
We shall now briefly discuss the relevance of such terminology, and in so doing we shall bring out the special aptness of the designations “true” and “false” to identify the possible values of a variable.现在我们将简要地讨论一下这些术语之间的关联,并在此过程中阐明用标示“真”和“假” 来识别一个变量的可能值的特殊用途。
Just as other algebras deal with variables which have a numerical significance, Boolean algebra deals with propositions and is an effective tool for analyzing the relationships between propositions which allow only two mutually exclusive alternatives.和其他处理有数字意义的变量的代数一样, 布尔代数处理的是命题, 而且布尔代数对于分析仅有两个互反变量命题之间的关系是一种有效的工具。
There is a generally prevailing attitude in digital systems to view logic 0 as a basic, undisturbed, unperturbed, quiescent state and to view the logic 1 state as the excited, active, effective state, i.e., the state arrived at “after something has happened.”在数字系统中,普遍的观点是把逻辑 0看成一个基本的、无干扰的、稳定的、静止的状态, 把逻辑 1看成一个激励的、活跃的、有效的状态,也就是说,这种状态是发生在“某种操作动作之后” 。
Such devices operate well in a two-state or binary system, using conduction and cutoff as the operating states, and as a result the binary number system is generally employed in internal operations in digital computers.将导通和关断作为工作状态, 这样的装置可以在两态即二进制系统中运行, 因此数字计算机中的内部操作一般采用二进制系统。
Given the basic idea of a chain of positive and negative, or positive and zero, or zero and negative pulses as representing binary 1s and 0s, there are many possible codes in which the pulses might be transmitted.给出一串正脉冲和负脉冲, 或正脉冲和零, 或者零和负脉冲来表示二进制的 1及0时, 就会有许多这些脉冲可以传递的码。
The reaction time of a human pilot is too slow to enable him or her to fly an aircraft with a lightly damped Dutch roll mode without a yaw damper system.飞行员的反应速度太慢, 如果不附加阻尼偏航系统, 飞行员就无法通过轻微阻尼的侧倾转向方式来驾驶飞机。
Since the output is fed back in a functional form determined by the nature of the feedback elements and then subtracted from the input…因为输出会以由反馈部件特性决定的函数形式反馈回来,然后从输入中减去……The designer quickly becomes adept in relating changes in the Laplace domain to behavior in the time domain without actually having to solve the system equations.设计人员很快就会熟练地把拉普拉斯域的变化与时域状态联系起来, 而不需真地解系统方程 (时域The table is continued horizontally and vertically until only zeros are obtained.这张表向水平(向右垂直(向下方向延伸,直到得到的都是零为止thus eliminating the velocity error, and by being introduced ahead of the point of entry of the disturbance into the system, eliminates the steady-state error resulting from a step in the disturbance.……,这样通过在系统扰动进入点之前引入(积分环节 ,可消除由扰动输入中的阶跃(成分导致的稳态误差。