1 00:00:04,400 --> 00:00:17,519 studying electrical circuit from first professor so in each year we study something more with me 2 00:00:17,519 --> 00:00:32,780 that is the new contents so firstly we are going to this is the index and as in something new 3 00:00:32,780 --> 00:00:49,100 there is the Kirchhoff's law. You know it's something that is in the matter. 4 00:00:49,100 --> 00:01:01,899 The matter has been created linking molecules, but molecules also have been 5 00:01:01,899 --> 00:01:10,980 created linking atoms and inside the atoms you have particles which has 6 00:01:10,980 --> 00:01:18,939 electric charge. So electricity is something that is always associated with 7 00:01:18,939 --> 00:01:31,209 matter. If you have matter you have electricity. A little bit different is 8 00:01:31,209 --> 00:01:41,829 that the church can move and in this particular case you can transform electrical energy into 9 00:01:41,829 --> 00:01:52,930 another kinds of electricity. You can also have electricity in some matter, in some elements, 10 00:01:52,930 --> 00:01:59,890 which usually called semiconductors. There are semiconductors because sometimes there 11 00:01:59,890 --> 00:02:08,330 insulators they don't let they don't they don't let the movements of the 12 00:02:08,330 --> 00:02:15,650 churches inside them or in in other circumstances they can be conductors 13 00:02:15,650 --> 00:02:26,110 this is for example one of the of the best samples could be a silicon so in 14 00:02:26,110 --> 00:02:39,949 In this case, for example, silicon can break their links because of temperatures or because you give silicon sun energy. 15 00:02:39,949 --> 00:02:53,210 In this particular case, you can form a hole, which is a positive charge itself. 16 00:02:53,210 --> 00:03:01,210 but you can also have a free electron that can move into the net of the silicon. 17 00:03:01,210 --> 00:03:15,210 You can also have this effect if you interchange one atom in the net of silicon with another particle, 18 00:03:15,210 --> 00:03:28,870 That can be, for example, boron or can be, for example, we have excess of electron or it has a defect of electron, so it has holes. 19 00:03:28,870 --> 00:03:42,969 This is the basis of electronic, because if we put in contact one semiconductor with half 20 00:03:42,969 --> 00:03:51,330 x-axis of electron with another we have defect, the charges tend to move and it's the main 21 00:03:51,330 --> 00:04:00,550 effect of electronic. 22 00:04:00,550 --> 00:04:11,310 The circuits usually have at least five types of elements, which are something that gives 23 00:04:11,310 --> 00:04:23,089 power to the circuit, another element which transforms electricity into another types 24 00:04:23,089 --> 00:04:28,170 of energies. 25 00:04:28,170 --> 00:04:37,709 So in this church you have the main magnitudes that you need to study a electrical circuit. 26 00:04:37,709 --> 00:04:46,250 We have church, we have resistance, which is the opposition of the materials to the 27 00:04:46,250 --> 00:04:55,610 movement of the churches itself, current, load or charge per unit of time, voltat, energy 28 00:04:55,610 --> 00:05:08,170 that you need to move it up into an electrical field, electric power and electric energy. 29 00:05:08,170 --> 00:05:16,110 And you can also have the units, the symbols of some equations that help you to calculate 30 00:05:16,110 --> 00:05:17,110 these magnitudes. 31 00:05:17,110 --> 00:05:34,240 In any circuit you usually have three or five different types of elements, which are something 32 00:05:34,240 --> 00:05:42,420 that provides energy, which usually called generators or batteries, you also have something 33 00:05:42,420 --> 00:05:56,319 that transforms this energy into another type of energy, such as kinetic or light or sound, 34 00:05:56,319 --> 00:06:06,500 something that helps you to control this transformation and you also have something to protect, for 35 00:06:06,500 --> 00:06:17,319 For example, human people or also the active part of the circuit. 36 00:06:17,319 --> 00:06:26,139 Here you also have, for example, some instruments that help you to do measures. 37 00:06:26,139 --> 00:06:40,759 have the symbols of these parts and also the function. Sorry because it is in Spanish, 38 00:06:40,759 --> 00:06:57,300 I haven't translated it in English. Well, the most important law to know and to do calculations 39 00:06:57,300 --> 00:07:02,519 electrical circuit is obviously Ohm's law and it is the Ohm's law is an 40 00:07:02,519 --> 00:07:14,819 experimental law which can be summarized saying that the voltage is you can have 41 00:07:14,819 --> 00:07:24,180 the voltage with this expression. It is very usual that you use a triangle as an 42 00:07:24,180 --> 00:07:40,149 mnemothetnik rule. And here you have an example of application of Ohm's law. You have a very simple 43 00:07:41,029 --> 00:07:54,310 circuit which has been simulated with cocodrille. You already know cocodrille as a tool to design 44 00:07:54,310 --> 00:08:06,129 and simulate circuits so in this circuit you have a battery which is 5 volts and which has a bulb 45 00:08:06,129 --> 00:08:17,410 a bulb or lamp which have a region with you that you don't know the value of the resistance but 46 00:08:17,410 --> 00:08:31,670 But with an amperement you can know that the intensity of current is 50 mA. 47 00:08:31,670 --> 00:08:37,129 So as you have here is the value in ampere. 48 00:08:37,129 --> 00:08:50,350 So you can calculate very easily the value of the resistance in this area. 49 00:08:50,350 --> 00:08:59,870 obviously you usually have more than one element so the the different elements can be associating 50 00:08:59,870 --> 00:09:09,549 into in two ways in serie as you have in this picture which means that the intensity current 51 00:09:09,549 --> 00:09:20,029 is the same for both elements and just application the ohms law and energy balance you can calculate 52 00:09:20,029 --> 00:09:29,730 that the equivalent resistance is the addition of the value of the resistance and using the 53 00:09:29,730 --> 00:09:44,049 Onslaught you also calculate the other parameters. As I said, the resistance is in parallel, 54 00:09:44,049 --> 00:09:57,620 it is in this way, in parallel both resistance are the same voltage but the intensity obviously 55 00:09:57,620 --> 00:10:11,779 divided in this point. So using the balance energy you can calculate the 56 00:10:11,779 --> 00:10:17,299 resistance equivalent with this expression and also the rest of the 57 00:10:17,299 --> 00:10:31,580 parameters. Well, there is something that is not true. The balance doesn't take into 58 00:10:31,580 --> 00:10:38,659 consideration that a part of energy can be 59 00:10:38,659 --> 00:10:48,740 transform it into heat is what usually call Joule's effect so these calculations aren't very very 60 00:10:51,539 --> 00:10:53,539 no they're they're aren't 61 00:10:56,179 --> 00:11:04,179 very exactly exactly but well in in this particular case we can 62 00:11:04,179 --> 00:11:21,240 we can do this calculation because it could be true. Well, it can be explained and can be 63 00:11:21,240 --> 00:11:33,960 summarized in what we usually call the Kirchhoff's law. In a very complex circuit you can have a knot, 64 00:11:33,960 --> 00:11:44,639 which is a point in which you have more than one conductors and in this point the intensity input 65 00:11:44,639 --> 00:11:55,279 and the sum of the addition in the inputs intensities must be the same that the addition 66 00:11:55,279 --> 00:12:07,340 in the output intensities. A mesh with in a mesh you can know the the intensity is 67 00:12:07,340 --> 00:12:14,460 something is a closed circuit but you also have for example branch and 68 00:12:14,460 --> 00:12:27,539 another part of circuit. Very useful in a very compressed circuits for example 69 00:12:27,539 --> 00:12:38,419 this one, in this circuit you have two meshes, you have one branch and we have two nodes, 70 00:12:38,419 --> 00:12:52,659 so if you take into consideration the Kirchhoff's law you can solve this circuit, you can know 71 00:12:52,659 --> 00:13:00,899 intensity in each element and also the voltage in this element. So here you have, for example, 72 00:13:02,340 --> 00:13:12,100 you have for one mesh this expression that is the application of Ohm's law and in the 73 00:13:12,100 --> 00:13:21,860 other this one. So in the end it is a system of equations and it's very easy to solve. 74 00:13:28,070 --> 00:13:39,070 I hope this tutorial has been helpful.