[VẬT LÝ 12] ĐIỆN XOAY CHIỀU - MẠCH RLrC MẮC NỐI TIẾP - THẦY VNA

Hello, I'm Ngoc Anh. Today, I'm going to show you the theory and the exercise of the connected R-L-R-C circuit. You can see that it always has a small r part. What is this small r? That is, our circuit is a non-symmetric circuit. The previous lesson, I learned that the connected R-L-C circuit is a non-symmetric circuit with a voltage in the small r equal to 0. In this lesson, I will add another small r part. So our circuit is from 3 parts of R-L-C to 4 parts of R-L-R-C. So, adding one more part, will it be more difficult and complicated? Of course, it will be more difficult and complicated. Because adding one more vector, adding one more matrix, the shape will be more complex. The formula will also be more complex. But the difficulty of it will be felt later when we have learned the methods. For example, the method of subtracting the origin, subtracting the connected element, or the method of multiplying the origin, or the method of addition. It is only difficult when you learn a lot of knowledge. There are first lessons like this. You just need to apply the basic formula, apply the nature of the problem, and you will be able to solve the equation correctly. Today, I will give you the theory and the exercise to get used to when solving the R-L-R-C circuit. Let's go to the structure of the circuit. As you can see, our circuit is still R-L-C. But now, our circuit is an imperfect circuit. That is, there will be transistors inside it. Because it is made up of these wires. These wires themselves have transistors, right? So it is called an imperfect circuit or a circuit with transistors. So later, for example, people give a L-shaped circuit. But the word L-shaped circuit is divided into two situations. Our L-shaped circuit may be pure. That is, the transistors inside are empty. Or the imperfect circuit, the transistors inside are empty. This is an imperfect circuit. But people can say that it is just a circuit. You have to divide the cases. So you can understand this circuit as follows. It is R-L-R-C. There is a small R-shaped transistor inside, right? I can understand it as follows. I separate it, this small R-shaped transistor, out. That is, consider this branch of ours, this section of our circuit. It is R connected to L. It is a pure transistor connected to a L-shaped transistor. Let me see it as it is. In fact, I can't separate it like this. I see it as it is. So our circuit will have all the particles, guys. It has 4 particles. I consider it as 4 particles. It is R-L-R-C. Right? So you see, here are 2 R-connected transistors. Right? These are 2 R-connected transistors, right? The equivalent of 2 R-connected transistors, learned from 9th grade, is to take this R plus this R. So our total transistors formula is as follows. It is Z square. Z is the square root of R plus R. Plus ZL minus ZC square. Right? So you see, in fact, this R plus R is the total transistors. Got it? The transistors in the circuit. The pure R transistors and the transistors in the small R. Got it? Normally, I just write R square, right? But we have 2 R. So it will be R plus R square. Got it? This is the total transistors formula. Next, the transformer voltage formula. It is R square plus R square plus UL minus UC square. It is the upper part times both V and I. Right? I will prove it later. It is very easy. It is based on the equation. Got it? In fact, it is simple. We have another small R. We take the small R and add it to the big R. Got it? You see, this is a R. This is also a R. Got it? This is the circuit structure. There are 4 parts R, L, R, C. So you see, with a circuit that has only 3 parts R, L, R, I will remove C. Got it? So our total transistors formula is Z square of R plus R square plus ZL square. We consider ZC to be 0. Got it? We consider ZC to be 0. Got it? So there is only ZL square. Because our circuit does not contain C. Got it? This is just plus ZL square. Got it? And similarly, the total transistors formula is U square of U R square plus U R square plus U L square. It is like losing the guy UC and ZC. That is, 3, 4 is the presence of 1, 2 but losing UC and ZC. Got it? Our circuit is this circuit. And this circuit is the two circuits that are often encountered with our R transistors. Is it different? Got it? This is a circuit with an imprecise circuit. Let's go to part 25, the vector equation. So here you can see, the teacher still took our vector Y as 5,000. Right? And now our circuit has 4 quadrants. Right? R, L, R, C. So we will have 2 U R. Right? Small U R and large U R. It is still a capacitor. So the voltage through any capacitor is still mixed with the current in the circuit. So small U R is mixed with Y and our large U R is also mixed with Y. U L is still mixed with Y and U C is still mixed with Y. Got it? So now you look at this. Our U vector will be a combination of several vectors. Our U vector will be a combination of 4 vectors. U L vector, small U R vector, large U R vector, and U C vector. Got it? So now, what kind of combination of these 4 vectors? You will combine the same direction. Right? U L and U C are in the same direction, but in the opposite direction. Got it? So in summary, U L C will be perpendicular to the larger side. Got it? Right? It is U L. U L is larger so it will be perpendicular to U L. And U C has a length equal to U L minus U C. Next, we have small U R and large U R are in the same direction. So we will combine the combination of small U R and large U R to get U R plus small R. Got it? It is like this. There. It has a length like this. Here, we have 4 vectors. These 4 vectors all have the same origin. Got it? In today's lesson, we haven't learned about the method of minimizing the origin vector. But in fact, the method of minimizing the origin vector is this one. Right? It is this one. So, the length of U R plus small R is the length of U R plus large U R plus this one. Got it? This one plus this one is this one. Got it? So, we have U R plus small R and U L C. Now, we combine these 2 vectors according to the equation. Got it? Here. According to the equation. There are 4 vectors. So, we combine 2 vectors. Right? There are 4 vectors. U L, U C are together. U R, U R are together. 4 vectors, right? After combining 4 vectors, we have 2 vectors. In this case, we have 2 vectors. In this case, we have 2 vectors. Now, we have U R plus small R. Here. Right? So, U R plus small R is here. What is it? It is the tangent. It is this tangent. It is U R plus small R. Got it? It is this tangent. It is U L plus U C. Got it? It is the tangent in this rectangle. Got it? So, we have the length of U and from U we have Z. Got it? From here, we have this. But normally, we have Z first. It is the tangent first. It is easier for you to understand. Alright. Now, we know the equation of U. Now, what is the angle between U and Y? The angle between U and Y is called the angle Phi. Got it? So, how many equations of Phi do we have? We have 3 equations of Phi according to tan, cot and sin. Right? The first one is tan Phi. Tan Phi. What is it? It is the tangent. Right? It is the tangent. The tangent is U L C. The tangent is U R plus R. Got it? I will write Z to make it more beautiful. U L C is equal to Z L C which is Z L minus Z C. Got it? There. Divide it by R plus R. And then, I will write this tangent again. Got it? I usually use the magnitude. Alright. This is the equation of tan Phi. Many of you will develop it according to U. I always say U L C is U L minus U C. It is equal to Z L minus Z C in the ratio. Got it? The ratio of U is also the ratio of Z. Alright? I have the equation of tan Phi. I will continue to use it. There. There are some equations which are related to cot. Right? The tangent of Phi is the tangent divided by the tangent. Our tangent is U R plus R. The tangent is U. U R plus R is equal to R plus R. It is the opposite. The tangent is the tangent divided by the tangent. What is the tangent? It is the equation of tan Phi. Right? It is a bit complicated. As I said, the tangent looks neat but the tangent itself is complicated. Got it? Next, the equation of sin Phi. Got it? Sin Phi. Sin is the tangent divided by the tangent. Right? It is the tangent of Z L minus Z C divided by the tangent. Got it? I will write it again. Alright? The magnitude. Alright? The magnitude is the tangent of Z L minus Z C divided by the tangent. Got it? The magnitude is the tangent of Z L minus Z C divided by the tangent. Got it? Remember this. Of course, it will be like this. Got it? The tangent is equal to the tangent of Z L minus Z C divided by the tangent. It will be longer when we add a bit more. Alright? The magnitude is the tangent of Z L minus Z C divided by the tangent of Z L minus Z C divided by the tangent of Z L minus Z C divided by the tangent of Z L minus Z C divided by the tangent of Z L minus Z C divided by the tangent of Z L minus Z C divided by the tangent of Z L minus Z C divided by the tangent of Z L minus Z C divided by the tangent of Z L minus Z C divided by the tangent of Z L minus Z C divided by the tangent of Z L minus Z C divided by the tangent of Z L minus Z C divided by the tangent of Z L minus Z C divided by the tangent of Z L minus Z C divided by the tangent of Z L minus Z C divided by the tangent of Z L minus Z C divided by the tangent of Z L minus Z C divided by the tangent of Z L minus Z C divided by the tangent of Z L minus Z C divided by the tangent of Z L minus Z C divided by the tangent of Z L minus Z C divided by the tangent of Z L minus Z C divided by the tangent of Z L minus Z C divided by the tangent of Z L minus Z C divided by the tangent of Z L 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