交流电“四值”辩析

交流电的瞬时值、最大值、有效值、平均值的意义不同,只有充分理解其内涵,才能正确运用,减少失误,现例析如下:一、有效值与平均值交流电有效值是利用电流的热效应定义的,即交变电流通过某一电阻时产生的热量与直流电通过同一电阻在相同时间内产生的热量相等,则直流电的数值就是该交变电流的有效值,有效值用来计算电功率、电热等,交变电流表读数和用电器标定值均为有效值.     

例谈直流电路中几类题的解法探索

一、测电源电动势和内电阻的系统误差（一）基本原理闭合电路欧姆定律.原理图如图1所示.由E=U+Ir可知,测出几组U、I值,根据闭合电路欧姆定律,由两次测量列方程组为:（?）解得:E=（U₁I₂-U₂I₁）/（I₂-I₁）,r=（U₁-U₂）/（I₂-I₁）闭合电键K,改变滑动变阻器值,也可测出对应的多组U、I值,根据测出的U、I值作出如图2所示的U-I图象的直线,由E=U+Ir得:U=E-Ir知:I=0知U=E,当U=0时,I=E/r图象的斜率的绝对     

直流电路中电感线圈的动态分析

本文分析了电感线圈中通过变化的直流电流时"电感电流"不能突变的原因,以及"电感电流"随时间变化的动态过程.     

微波驻波自动测量实验系统的设计与实现

为了探索微波教学实验与CAI相结合的创新教学模式,利用单片机控制、计算机接口技术等,研制了一套微波驻波自动测量教学实验系统．该系统由微波测量线、PC机、单片机控制模块、数字微电流检流计、步进电机及其驱动电路等设备组成．在测量过程中,计算机按照用户预先编制的程序,模拟手动测量的方法和步骤控制系统进行自动测量,得到的数据经过电流／电压转换、放大和单片机A／D采集后输入计算机中,并将结果通过LabVIEW软件直观的图形显示出来．     

填埋场渗漏检测高压直流电法两种模型的比较

To solve the disability of conventional model used in electrical leak location when measurement electrodes were buried under the liner, a new model of high voltage DC leak detection is developed. For single-liner landfill, the waste material layer, the geomembrane liner and the soil under the liner are simulated with infinite horizontal layers. The leak is regarded as two parts, one being negative current source at the entrance, and the other positive current source of the same size at the exit. Comparisons between the new theoretical model and conventional model show that conventional model is efficient in locating leaks in geomembane liner associating the dipole scanning above the liner but is ineffective when the measurement electrodes were buried under the liner. The new theoretical model data are in excellent agreement with experimental data not only above the liner but also under the liner.     

超约B_4C粉末的直流电弧法制备及扫描电镜研究

以填B4C固体粉末（粒径约1mm）的高纯石墨棒为阳极，以高纯石墨捧为阴极，在He气氛下，用直流电弧法制备出了超细B4C的粉末，扫描电镜（SEM）研究表明，该超细B4C粉末的形状有三种：球及合有空洞的球、树枝状的棒或管、细小的颗粒，这些球及颗粒的粒径分布在数十纳米到数十微米范围内．这为粉碎莫氏硬度为9.28的B4C固体找到了新的、简便、可行的方法．     

DC steady-states analysis of lossy uniform transmission lines

1 Introduction In the past 20 years with the rapid development of VLSI (very large scale integration) circuits and continual spread of electric power system scale, theories on transmission lines have become an important research field where finding the analytic solutions to lossy transmission line equations remains a tough nut. Since the mathematical tool cannot provide effective help, there is no universal method to solve transmission line equations [1]. A number of researchers have obtaine…     

利用橡皮泥制作起伏地表物理模型进行直流电法实验

目前室内直流电法实验大都在水槽里进行,所以要想得到起伏地表的实验结果是很难的。尽管土和沙子可以制作成起伏地表模型,但是都有各自的优缺点。采用橡皮泥制作模型实现了起伏地表的实验,为今后在室内进行直流电法实验找到了一种简单易行的方法。