english 4 bkfwqgh31gứa;;kfaqưkgkwq gưd fskfs sakfảowjfiwjjfwkfsdhfshfsơjbfjwbsamkeqjkkfnadohfu0wqhnưkdfnksf0hưeuwbưdbjsbjdjfjdnfmmqkkamdmakdạiahfan;ầhuqhbfjbfr ưueh ưhưhhfhf;shfjdhjfhshfuhùuwsfbsds Trong mạch có 2 chân đầu ra là Aout và Dout. Trong đó: o Aout: điện áp ra tương tự. Nó chạy từ 0.3à4.5V, phụ thuộc vào nồng độ khí xung quang MQ2. o Dout: điện áp ra số, giá trị 0,1 phụ thuộc vào điện áp tham chiếu và nồng độ khí mà MQ2 đo được. o Việc có chân ra số Dout rất tiện cho ta mắc các ứng dụng đơn giản, không cần đến vi điều khiển. Khi đó ta chỉ cần chỉnh giá trị biến trở tới giá trị nồng độ ta muốn cảnh báo. Khi nồng độ MQ2 đo được thấp hơn mức cho phép thì Dout = 1. Đèn Led tắt. Khi nồng độ khí đo được lớn hơn nồng khí cho phép, Dout =0, đèn led sáng. o Ta có thể ghép nối vào mạch Realy để điều khiển bật tắt đèn, còi, hoặc thiết bị cảnh báo khác. Một điều khó khăn khi làm việc với MQ2 là chúng ta khó có thể quy từ điện áp Aout về giá trị nồng độ ppm. Rồi từ đó hiển thị và cảnh báo theo ppm. Do giá trị điện áp trả về từng loại khí khác nhau, lại bị ảnh hưởng nhiệt độ, độ ẩm nữa. Trong thiết bị của mình, để xác định điểm cảnh báo mình làm khá thủ công. o Đầu tiên đo trạng thái không khí sạch, giá trị thu được Vout1 o Cho khí ga từ bật lửa rò rỉ ra. Ta thấy giá trị Aout tăng lên. Khi đạt khoảng cách khí ga từ bật lửa hợp lý rồi tương ứng với nồng độ khí bắt đầu nguy hiểm, ta ghi lại giá trị Vout2. Ta chọn giá trị Vout2 là giá trị ngưỡng cảnh báo. Nếu giá trị đo được lớn hơn ta sẽ cảnh báo o Chỉnh chân biến trở để điện áp đo tại chân 3 của L358 = Vout2. Mình viết code trên Atmega8, anh em tham khảo nha.
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PRACTICE TEST – UNIT 789
PRONUNCIATION:
Choose the word whose underlined part is pronounced differently from that of the others:
Choose the word whose main stress is different from that of the others:
GRAMMAR, VOCABULARY & STRUCTURES:
Choose the best answer to complete each of the following sentences:
11 _A: So, how are you finding life here?
_B: Oh, it’s great But I a job
12 In distant future, space travel affordable for many people
13 People waiter for men and waitress for women, but now many people
server for both
14 Space vacations by 2025 Scientists still have many difficulties understanding
the universe
15 Due to the influence of globalization and internet, more and more people
English words to communicate
Trang 216 _A: How long for a job?
_B: A couple of months now I think I 10 applications this week alone
17 He hasn’t been able to in a big city It’s much more difficult and he always feels homesick
18 I’m sure the price of oil over the next few years
19 When I was studying Spanish, I down a few new words to learn every day
20 There high-speed long-distance trains underground in the future
21 Before the Internet, people access to so much information
22 Some changes in language noticeable because they over
hundreds of year
23 Your sense identity is how you feel yourself
25 He has no objections the fact that students are banned using slang in schools
26 There can sometimes be misunderstandings between people of different ethnic
backgrounds that result in
27 Economic migrants look overseas for better work _and an improved standard of living
28 Some people feel that the use of slang should be
29 Dictionary editors study data on the and popularity of new words
30 The word frenemy its meaning more quickly than standard language
31 The of migrants around the world is not even UAE is one of the top
destinations for migrants
Trang 332 With the interaction of people all over the world, we are able to experience a(n)
range of cultures and customs
33 New York City, also known as “the melting pot”, is one of the most _ cities in the world
34 There is a(n) of tourists every year in the summer This is the time when most
people like spending their vacation
35 People who by bus or train might have difficulty with walking long distances to
the bus stops
tools to observe language change
37 The use of slang people to communicate complex ideas effectively
38 Electric are not as fast as fuel-powered cars, but they are better for the
environment
39 The train was so packed this morning that I couldn’t I had to wait for the next one
40 The internet has resulted in new methods of learning and communication that were
previously
41 As cities have grown in size and population, scientists have come up with ways to improve
systems
42 Giant buses that drive over cars are an interesting means of transport which
reduces congestion
43 Since this vehicle solar power and electricity, it helps to reduce pollution
44 We can reduce our by walking or taking a public transportation
45 The introduction of new words can help the language
Trang 4CLOZE PASSAGE
Read the passage and choose the best answer to fill in each blank
Slang refers to words, phrases and uses that are (46) as very informal and often restricted to special context or peculiar to a specified profession class and the like Slang words (47) in specific social groups, like teenagers
In its earliest attested use (1756), the word slang referred to the vocabulary of "low or disreputable" people By the early nineteenth century, it was no longer exclusively associated with disreputable people, but continued to be applied to language use below the level of (48) educated speech The origin of the word is uncertain, although it appears (49) _connected with thieves' cant A Scandinavian origin has been proposed (compare, for example, Norwegian slengenavn, which means "nickname"), but is discounted by the Oxford English Dictionary based on "date and early associations" Jonathan Green however agrees with the possibility of a Scandinavian origin, suggesting the same root as that of sling, which means "to throw", and (50) _that slang is a thrown language - a quick, honest way to make your point
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