Hello everyone, welcome to the ZimZim DIY channel today. Of course, I will explain electrical equipment, simple electronic equipment in the style of the Zimzim channel. And the equipment I will talk about today is a transformer. Before talking about how the transformer works, I will talk about electric current first. The electric current that we use today is mainly 2 types, and I think most of my friends know it well. That is, alternating current, or what we often call Ac, and direct current, or what we call Dc. But our transformer will work only when it is alternating current. We can create alternating current by using a generator or dynamo to spin a permanent magnet to cut through the coil. This will result in alternating current like this. If we send direct current through the coil, a magnetic field will occur, but it will be constant. That is, there will be no induction. But if we send alternating current through the wire, the magnetic field will increase and decrease. And it will switch poles back and forth. If we use many copper wires, place them together, and pass current through them, we will get a stronger magnetic field. And when we change the shape From a single straight copper wire, it becomes a coil, the magnetic field will be even stronger. Therefore, if we wind another set of coils close together, and then we release the alternating current through the first coil, the first set of wires, it will automatically induce the electric current into the second coil. You will clearly see that the most important part that the current can flow through the transformer is using alternating current to create a magnetic field. Therefore, when we put these copper wires in the way, the free electrons in the wires will be disturbed by the magnetic field. They are not themselves like drunk people and can control the direction they walk. They are blown by the magnetic field, forcing them to go left and right. They obey, so the electrons move. This movement, we call it electromotive force or EMF. This electromotive force will not occur with DC current because the magnetic field is too constant. The electrons are not forced to move. But if I connect DC current and press the switch on/off, there will be a sudden change in the magnetic field in a short period of time. We will see a light bulb, bright enough to see, but in actual use, no one wants a flickering light. It's more like a broken light bulb. So if I want it to be consistently bright, I have to increase the rhythm. You will see that I can press the switch as fast as 5 times per second, which makes the light still flicker, not smooth. But for home lights, it can be turned on/off continuously like me, but it can be turned on/off much faster. It can do up to 50 times per second, or what we call 50Hz. At this speed, the light bulb will flicker so fast that our eyes cannot detect the movement of these lights in time. So we see that the light bulb is consistently bright and continuous. Let's look back at the transformer. Placing the coils close together can actually induce current, but it loses a huge amount of magnetic field in this gap. So engineers solved this problem by using iron as the core between the two coils. The first coil that we feed the current to is called the primary coil, and the other coil that is induced is called the secondary coil. When we place the iron core The magnetic field will be divided into the secondary coil, making the transformer more efficient. But when we use an iron core, there is still a problem. The problem is that some energy is lost from eddy currents. What is eddy current? It is a current that rotates around the iron core. When it rotates more, it will cause the transformer to heat up. So the engineers have to design a new iron rod again. This time, they will change to use laminated iron, stacked sheets instead, which helps reduce eddy currents very well. For example, a step-down transformer, we will wind more coils on the primary side than the secondary side. And for a step-up transformer, we will reverse it. We will wind more coils on the secondary side than the primary side. These transformers are very useful for power plants that need to transmit electricity over long distances because they will help reduce losses from resistance from long transmission lines. And importantly, it saves costs because the wires do not need to be large. But electrical transformers used for factories or large commercial buildings usually use 3-phase. As for 3-phase electricity, I will explain it in another half. Later, the transformers that we use in our homes are usually StepDown. We can design, choose to use as a sub-coil, choose to use different Vs freely. Now, the transformer has been developed into many forms, such as the toroidal transformer. Its shape is similar to a donut with a hole in the middle. It is a circle. It can be divided into many types of materials for making the core, such as iron cores and ferrite cores. However