问题 问答题 计算题

型号为2CP22的二极管V1和V2,最大整流电流为300mA,最高反向电压为200V。如果串联 使用于反向电压为300V的电路中,由于同类产品的差异V1的反向电阻为1M,V2的反向电阻为4M,求每只管子上的反向电压各是多少?这样使用有没有问题?

答案

参考答案:

V1管上反向电压为60V,V2管上反向电压为240V。使用有问题。

阅读理解

Deciding which English-speaking country to study in wasn’t difficult for Ann; She had always wanted to visit America. “I wanted to study in an  English-language country and I always wanted to visit America because it always seemed to me a very beautiful and friendly country.” Ann is more than happy with the quality of the education she is receiving in America, particularly with the subjects and strong academic support.“ I am very happy with the quality of education I am receiving. All my subjects are useful and connected. I am happy with help I receive from the lecturers and tutors.”

Also of particular satisfaction for Ann is the practical element of her American course. “I find it very important and useful. The theory is a good thing to know but nothing gives you more skills and knowledge than practical work.”

Where her future employment is concerned, Ann is very confident her American qualification will be of great help. “I know that getting a degree here is a good thing for my future; it can open many doors in Poland or anywhere  else in the world.

Ann is also really enjoying life in America; She is making friends and taking time out to enjoy herself. “People are very friendly and helpful. University is a good place to find new friends from America and from overseas. It is a friendly environment with lots of things to do, not only studying. And of course there are the beaches, not to mention the beautiful weather.”

小题1:The purpose of writing this passage is to _________.

A.tell us Ann’s decision to settle in America

B.tell us Ann is accustomed to life in America

C.introduce Ann’s happy study and life in America

D.introduce more about Ann to help her make friends小题2:Why did Ann decide to study in America?

A.Her parents persuaded her to do so.

B.She has relatives and best friends here.

C.Her boyfriend was studying here too then.

D.She has dreamed of studying here for long.小题3:What makes Ann particularly satisfied in America?

A.The comfortable climate and easy lifestyle.

B.The help from her host families and teachers.

C.The American courses have more practical elements.

D.The friends here are mostly from English-speaking countries.小题4:What does the underlined sentence mean?

A.Ann will try all her best to ensure to get a degree.

B.Ann’s degree will help her find a job easily at home and abroad.

C.Ann will certainly go back to Poland to work after graduation.

D.With the degree received in America, Ann will never be out of work.

单项选择题