1
00:00:00,240 --> 00:00:04,240
This unit is basic electricity and electronics.

2
00:00:04,240 --> 00:00:10,240
As we have studied all these years, this is the concept of atoms.

3
00:00:10,240 --> 00:00:20,239
They are formed by protons that are in the nucleus with positive charge and neutrons that don't have charge at all.

4
00:00:20,239 --> 00:00:30,239
Electrons with a negative charge, they are floating in clouds around the nucleus.

5
00:00:30,239 --> 00:00:38,810
In a balanced atom, the number of protons is equal to the number of electrons.

6
00:00:38,810 --> 00:00:45,810
Due to the forces of attraction and repulsion, these particles are balanced.

7
00:00:45,810 --> 00:01:05,769
What happens? There are certain types of atoms that are called metals, in which these electrons are so far away from the nucleus, because this is similar as the stars, sorry, as planets that are making orbits, that are orbiting around the star.

8
00:01:05,769 --> 00:01:28,209
When this electron or planet is really far from the nucleus, then there is a possibility in which another atom can attract with a bigger force these electrons, so these electrons start jumping from one atom to another.

9
00:01:28,209 --> 00:01:41,230
This is called electricity. This transfer of charge is the electrical current and is produced, as I said, in conductive materials that are called metals.

10
00:01:42,030 --> 00:01:54,290
Conductive materials transmit electricity and electric circuits is the path they use to allow this electrical current.

11
00:01:54,290 --> 00:02:01,290
Here you can see the difference between analog electronics and digital electronics.

12
00:02:01,290 --> 00:02:11,289
In analog electronics, we study systems in which current voltage can take any values over time.

13
00:02:11,289 --> 00:02:22,289
That means that, for example, you can have a current of 1.2 or 1.3 amperes or a voltage with decimal figures.

14
00:02:22,289 --> 00:02:33,289
But in digital electronics, we study circuits in which we only take and take discrete values,

15
00:02:33,289 --> 00:02:46,289
normally zeros and ones that represent the open and close of a circuit when you have a switch.

16
00:02:46,289 --> 00:02:55,289
Electronics is a branch of physics that studies the control of the movement of electrons between semiconducting materials.

17
00:02:55,289 --> 00:03:05,289
These materials allow or don't allow the pass of the electricity depending on the circumstances.

18
00:03:05,289 --> 00:03:13,289
Depending on certain factors, they can act as conductors.

19
00:03:13,289 --> 00:03:20,289
The most common semiconducting materials are silicon and germanium.

20
00:03:20,289 --> 00:03:27,289
As I said before, we can divide electronics into two branches, analog and digital.

21
00:03:27,289 --> 00:03:37,979
In electricity, we study the movement of electrons in conducting materials, but in electronics we also use semiconducting materials.

22
00:03:37,979 --> 00:03:45,979
The components in electrical currents are passive, that are resistors and capacitors.

23
00:03:45,979 --> 00:03:56,979
But in electronics we can use passive components and active components as diodes, transistors and integrated circuits.

24
00:03:56,979 --> 00:03:59,979
Let's remember what is the Ohm's law.

25
00:03:59,979 --> 00:04:06,939
the Ohm's law. The Ohm's law is the mathematical expression of the relation between the three

26
00:04:06,939 --> 00:04:14,780
main magnitudes in an electrical circuit that are current, voltage and resistance. Here

27
00:04:14,780 --> 00:04:20,819
you can see the statement that is that the intensity is equal to the voltage divided

28
00:04:20,819 --> 00:04:27,620
by the resistance. What is current? Current is the variable that says how many electrons

29
00:04:27,620 --> 00:04:34,019
are going through a cross section of a conductor the unit in the international system is the ampere

30
00:04:34,579 --> 00:04:40,980
current is represented by a letter i and ampere or amps is represented by a letter

31
00:04:40,980 --> 00:04:48,339
a voltage says what's the difference in the electrical circuit per unit of charge between

32
00:04:48,339 --> 00:04:56,819
two points it can also be named as electric potential difference or volt or drop potential

33
00:04:56,819 --> 00:05:03,459
The unit in the international system is the Volt, or less is the energy that we have in

34
00:05:03,459 --> 00:05:04,459
a circuit.

35
00:05:04,459 --> 00:05:09,000
So if the voltage is zero, we don't have a current at all.

36
00:05:09,000 --> 00:05:14,300
And the resistance is the variable that says the opposition to the electric current is

37
00:05:14,300 --> 00:05:17,339
represented by the letter Ohm.

38
00:05:17,339 --> 00:05:23,819
In this table, you have all the symbols of the units and the symbols of everything and

39
00:05:23,819 --> 00:05:25,860
the sub-multiples and multiples.

40
00:05:25,860 --> 00:05:33,339
first activity consists in trying to solve this exercise in the first

41
00:05:33,339 --> 00:05:39,639
exercise you have to convert these units kilo ohms into ohms so you only have to

42
00:05:39,639 --> 00:05:53,759
multiply by 1000 by 1000 so this is a result the next exercise 3k2 it's

43
00:05:53,759 --> 00:06:03,920
thousand plus two hundred so the result is three two zero zero ohms and the

44
00:06:03,920 --> 00:06:13,750
next one you have 47 kilo ohms so it's 47,000 ohms be careful the next one is

45
00:06:13,750 --> 00:06:20,649
given in milli ohms so you divide it by one thousand is four point seven ohms

46
00:06:20,649 --> 00:06:43,649
5mA is 0.05A, 6A is 6000mA, 2x10³mV is 2V and 3.6kV is 306mA.

47
00:06:43,649 --> 00:06:51,649
We are now calculating basic circuits with the Ohm's law.

48
00:06:51,649 --> 00:06:58,649
First one, calculate a current flowing through this circuit given that the cell is 5 volts and the resistance is 100 ohms.

49
00:06:58,649 --> 00:07:03,649
So the first thing is to write the Ohm's law.

50
00:07:03,649 --> 00:07:05,649
You have to write it.

51
00:07:05,649 --> 00:07:27,060
And then let's see that the missing value of the resistance is the one that I have to calculate. So resistance is equal to the voltage divided by the intensity.

52
00:07:27,060 --> 00:07:37,639
and then just solve it with the resistance will be the value of 5 volts divided by 100

53
00:07:37,639 --> 00:07:50,759
that if you take your calculator sorry it's 5 it is going to be 0.05 and remember that the unit

54
00:07:50,759 --> 00:08:06,339
is ohm. It's ohms. Sorry I cannot write it here. So here you can write that is 0.05 ohms and

55
00:08:08,579 --> 00:08:20,170
well you can write here this is 15 milli ohms but this is not. This is optional.

56
00:08:20,970 --> 00:08:25,769
In this exercise you have to calculate the voltage that the power source of a circuit

57
00:08:25,769 --> 00:08:33,049
with a resistance of 2 kilo ohms must have to allow a current of 2 milli amperes let's make

58
00:08:33,049 --> 00:08:40,889
the calculations again voltage is equal to the intensity by the resistance if you remember the

59
00:08:40,889 --> 00:08:48,009
triangle of the layer of the ohms law and you can remember all the expressions for the ohms law

60
00:08:48,009 --> 00:08:52,330
but in this case we don't have to do anything because the voltage is equal to the intensity

61
00:08:52,330 --> 00:08:59,690
and the resistance that is something that they give us you can do it in to have two options

62
00:09:00,889 --> 00:09:07,289
you know that the intensity is two milliamps that is 0.002 amperes

63
00:09:09,289 --> 00:09:17,289
by um the resistance that is two kilo ohms so this is the operation that you have to do

64
00:09:17,289 --> 00:09:26,029
and the result is going to be if you use your calculator for words another way to do it is

65
00:09:26,029 --> 00:09:39,909
that if you see that two milli amperes and two kilo ohms this milli and kilo they are going to

66
00:09:39,909 --> 00:09:53,350
be simplified because milli means 4, 2, 2 minus 3 and kilo means 2, 2, 2, 3, sorry 2, 10, 2, 3 and milli

67
00:09:53,350 --> 00:10:02,289
10, 2 minus 3, this milli and kilo are going to be simplified and the result is 4 by 4, that is 4

68
00:10:02,289 --> 00:10:10,289
words so your result here is four words now you are going to do exercises from part one