[VẬT LÝ 9] Buổi 1: Chữa bài tập mạch điện và Định luật Ohm - Thầy Vũ Ngọc Anh

I will have lesson 1 See? I will give you 3 capacitors R1 equals R2 equals R3 equals 4 ohm See? The unit of the capacitor is ohm See? Lesson 1 has 2 sentences See? It is as follows R1 is like this See? Can you read this circuit? It is quite easy to read It will get more complicated See? The equivalent resistance of this circuit is R123 equals See? R123 equals B has 3 capacitors but we have a different voltage We have 3 capacitors but we have a different voltage It is as follows R1 is like this R2 is like this And R3 is like this See? So, with these 3 capacitors we will have all the voltage Actually, after this lesson If I'm not mistaken, there are 4 ways to do it Ok? And these are the 2 ways The other 2 ways are 3 guys connecting Then 3 guys parallel, right? These are 2 of the 4 ways And these are the 2 most difficult ways Now, let's calculate the equivalent voltage Have you written it down? Give us 1 minute to write it down and do this Ok? Now Write it down Give us 1 minute to write it down and do this Have you read the circuit? Now the circuit is mixed The circuit is done when it's done Connected when it's connected Got it? After 1 minute Have you written it down and done it? Now First, I will show you a sample Then the difficulty level will gradually increase For example, question A We have a circuit like this Our circuit Let me show you Our circuit is like this Our circuit Can you read it? That's what it looks like Our 2 and 3 guys are parallel So this circuit is definitely 2 eyes parallel to 3 And how about 1 guys? You have to look at a total eye You have to look at 2 and 3 It has an equivalent resistor It's R23 You guys put this together Right? Put it together Consider it as R23 At this time, our R23 is How about R1 guys? Connected to R1 So our circuit is R1 NT Is connected to a circuit Is 2 parallel to 3 This is the eye of the circuit of question A Is R1 eye connected to R2 parallel to R3 That is, R1 eye connected to this whole thing The whole thing of 2 parallel to 3 So how to calculate the equivalent resistor of this circuit We calculate from inside out Do you hear me? I calculate from inside out Guys I will have the following Plus the first line Because R2 is parallel to R3 Be careful, don't put it in Because R2 is parallel to R3 So calculate the equivalent resistor Do you understand? Students can skip this sentence Calculate the equivalent resistor We have to consider R2 and R3 have an equivalent resistor A representative for 2 and 3 R2 and R3 have an equivalent resistor The equivalent resistor is R23 Do you hear me? The equivalent resistor R23 Will be 2.1 part R23 Equivalent to 1 part R2 Plus 1 part R3 And I calculated R23 You substitute the number 1 part 4 plus 1 part 4 Do you hear me? It's 1 part 2 And we get 2 ohms There are 3 ohms Ah, that's one thing Because R2 and R3 are parallel Let's continue Because of R1 No one writes this column again No one writes a column like the first one I have calculated the equivalent resistor of this circuit I have calculated the equivalent resistor of it It's R23 I will write R1 Because R1 is parallel to R23 Do you hear me? So calculate the equivalent resistor Don't write it again R123 is Let's sum it up Subtract the number 1 So it's all in It's R123 Because it's parallel It's R1 plus R23 How many ohms? 6 ohms So the equivalent resistor of this circuit How many ohms? The equivalent resistor of this circuit It's 6 ohms Do you hear me? If it's parallel, it's 1 part 1 part plus 1 part It's parallel If it's parallel, it's Plus directly Are you done? So our A circuit The answer is 6 ohms This is the result of column A Next is column B Let's go to column B I will draw the circuit of column B How is it? Look at this Our circuit Remember I just read from small to large Read from inside to outside Look Here will be 1 and 2 Is it parallel? Right? What is parallel? Parallel is connected R1 is connected to R2 And this whole thing Let's say it's R12 And R12 is parallel to What? R3 Right? So what is our circuit? The circuit I will draw the circuit again Our circuit I will draw the circuit again There That is Open circuit R1 Mark NT Connected to R2 All parallel to R3 See? There Ok? Let's say R1, R2 is a column And Mark is parallel to R3 From here, can you calculate the equivalent resistance? I will write This must be multiplied by 7 Because R1 Right? Because R1 is connected to R2 So the equivalent resistance I will turn off See? The equivalent resistance R12 is R12 is equal to R1 plus R2 Right? How many grams? 4 plus 4 is 8 grams Done See? Next Because Right? R12 Now this whole thing Is R12 Parallel to R3 There I have called the equivalent resistance R12 I don't even write the beginning It's a waste of paper Right? Because R12 is parallel to R3 The equivalent resistance See? R123 is 1 part R123 Parallel to R3 It must be 1 part R Right? 1 part R12 Plus 1 part R3 From here, can you calculate R123? How much? Calculate by the calculator 1 part 4 Plus 1 part 8 Right? Let me press the button See? I got it wrong 12 part 32 Right? 12 part 32 Let me press the button See? 1 part 4 plus 1 part 8 Right? 1 part answer How can I get this number wrong? It's 8 part 3 ohm Ok Got it? Just the number This question is a bit tricky It's 8 part 3 This is the equivalent resistance Of what? R123 of the whole circuit These are the 2 most basic circuits Of the 3 resistors I don't include the 3 parallel resistors This is the combination of parallel resistors And parallel resistors Got it? Ok This is how to do it Ok I delete it I go to the 2nd lesson I still keep this question For you to see Ok Write down the question and the answer 3 questions We finish today Go home I will give you more complicated questions Got it? Ok The 2nd question I will increase it to 4 resistors 4 resistors It's more eye-catching You learn this part well Really Go to level 11 It's great But I'm afraid I forget So Go through level 10 The theory of 10 is quite difficult The theory of 10 has nothing to do with 9 That's good The theory of 10 makes you forget a lot In level 11, you forget everything Got it? In level 11, you forget quite a lot Ok You forget quite a lot After finishing level 10 Ok I have the 2nd lesson I still give R1 Equals R2 Equals R3 Equals R4 Equals 2 ohm Still basic questions Got it? But I only give 1 question It's quite difficult Here R1 outside Got it? Inside Here I have R2 Got it? Ok How difficult is it? Here Like this R3 And R4 Got it? Here 1 question Got it? Here Question A Question B These 4 guys have a lot of eyes You sit and draw Do they have 9 eyes? I don't remember exactly They have a lot of eyes Got it? A lot of eyes Here is R1 R2 After this, I will learn the rules of subtracting and subtracting Here is R3 Here is R4 Got it? Ok The question is quite simple With both meanings Find the equivalent resistor R1234 Got it? You check and do these 2 questions I haven't used a little bit about the law of ohm yet In the exercise, you will see I prefer to learn the theory, right? Learning the theory is a bit difficult It's always difficult to learn the theory But today you have finished the first 6 lessons of class 11 The day after tomorrow, you have to practice The day after tomorrow, you haven't finished the new lesson yet The day after tomorrow, you will fail Here Today I have finished 6 lessons In total, there are 62 lessons of class 9 Right? So, in this situation We will learn 10 sessions See? The program of class 9 will be finished In 1 month, you will have 6 sessions In 2 months, you will finish In October, you have finished the entire class 9 In September, the class 9 is just started In October, you have finished the program That's it I have to practice more I can only learn 6 songs in 1 session but I have to practice 2-3 sessions I have to practice a few sessions and learn a lot of songs to be able to do this part not just learn 6 songs in 1 session I'm so good, right? I'm confident that when I'm in 9th grade I'll be almost done with the show I'll be like a god I'll be sitting in class like a god exactly like a god Done? It's 9.27 I'll try my best Today is the first day It took me 10 minutes to introduce I'll draw the A part again It'll be a bit complicated To draw the A part you have to look at it from the inside look at it from the outside Can you see it? Here I have R3 eyes connected to R4 Look at it from the small to the big R3 connected to R4 The eyes have to look at the smallest part See? R3 connected to R4 and this part is parallel to R2 parallel to R2 Done? And this part is connected to R1 The inside is round The bigger part is the square This part is connected to R1 This is the parallel part There's a missing word It's our part See? R3 connected to R4 Everything is parallel to R2 to connect to R1 See? R3 connected to R4 Everything is parallel to R2 Everything is connected to R1 Right? There's a hack here We don't need a computer Because R3 connected to R4 then the electric field is equal to R34 R4 Because it's parallel R34 is simply R3 plus R4 See? 2 plus 2 is equal to 4 ohms That's the first point Because R3 connected to R4 Next This is R34 R34 parallel to R2 is also parallel See? R234 is 1 part R234 Right? Because it's parallel 1 part R234 is 1 part R2 plus 1 part R34 This is R34 parallel to R2 1 part 1 part 2 plus 1 part 4 is equal to 6 part 8 The opposite is 4 part 3 See? R234 is equal to 4 part 3 ohms The unit If you don't have the word ohm, you lose points Let's try 1 part 2 plus 1 part 4 The opposite is 4 part 3 The opposite is 4 part 3 See? Next R234 parallel to R1 is equal to R1234 See? R1234 is parallel to R1234 is equal to R1234 is equal to R1234 See? R1 is 2 2 plus 4 part 3 is equal to 10 part 3 10 part 3 Ohm See? My brain can be wrong Let's try 1 plus 1 is equal to 10 part 3 ohm Let's try It's quite easy See? R1 is parallel to R2 R1 is parallel to R3 R1 is parallel to R4 1 part R12