6.1 PWM控制的基本原理 6.2 PWM逆变电路及其控制方法 6.3 PWM跟踪控制技术 6.4 PWM整流电路及其控制方法

5.1 换流方式 5.2 电压型逆变电路 5.3 电流型逆变电路 5.4 多重逆变电路和多电平逆变电路

Students will be able to 1. understand the main idea and the structure of the text. 2 earn to memorize words in association 3. grasp the key language points and grammatical structures in the text 4. conduct a series of reading, listening speaking and writing activities related to the theme of the unit

Objectives Students will be able to: 1. understand the main idea (Bill Porter the salesman will never give in) and structure of the text (4 parts, 2 flashbacks); 2. appreciate the characteristics of journalistic writing; 3. grasp the key language points and grammatical structures in the text;

Objectives Students will be able to: 1. understand the main idea(cloning is a two- edged sword) and structure of the text; 2. appreciate the writing strategies employed by the author, 3. master the key language points and grammatical structures in the text;

Students will be able to: 1. understand the main idea and structure of the text; 2. appreciate how the repeated use of clues helps weave a piece of narration together; 3. grasp the key language points and grammatical structure in the text

At least 90 percent of UFO sightings can be identified as conventional objects, although time-consuming investigations are often necessary for such identification. The objects most often mistaken for UFOs are bright planets and stars aircraft, birds, balloons kites aerial flares, peculiar clouds, meteors and satellites. The remaining sightings most likely can be attributed to other mistaken sightings or to inaccurate reporting hoaxes or delusions although to disprove all claims made about UFOs is impossible

RLC串联电路的阶跃响应 一、实验目的 1.研究RLC串联电路的电路参数与阶跃响应的关系 2.观测二阶电路在过阻尼、临界阻尼和欠阻尼三 种情况下的响应波形。利用响应波形,计算二 阶电路响应过程的有关参数。 二、实验设备 1.函数信号发生器 2.双踪示波器 3.模拟电路实验箱

交流仪器的使用(一) 一、实验目的 1.掌握信号源、示波器的使用方法; 2.了解示波器测量交流电压及时间参数的基本方法; 3.学习用示波器观测和分析动态电路的过渡过程 二、实验设备 函数信号发生器、双踪示波器

交流仪器的使用(二) 一、实验目的 1.熟练掌握示波器、信号源和交流毫伏表的使用方法; 2学习相位差的测试方法。 二、实验设备 交流毫伏表、函数信号发生器 双踪示波器、模拟电路实验箱