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Series and parallel circuits - Contenido educativo

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Subido el 26 de julio de 2023 por Ivan P.

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hi good morning to everyone here we are I'm going to explain the the end of the 00:00:00
the unit okay and don't worry if you haven't understand everything till now 00:00:09
because we are going to have a we are half we are going to have one or maybe 00:00:18
one more than one online classes to explain all your questions okay so this 00:00:26
last part will be explained in this video okay and I'm going to explain the 00:00:36
things that I I think are more important in the unit of electricity okay so and 00:00:45
before this okay you have calculated some values using the Ohm's law we're 00:00:56
going to do more exercises but because I think you have some doubts about about 00:01:05
it but just before we're going to conclude the unit explaining the types 00:01:13
of circuits okay there are three these three circuits are the the types of 00:01:21
circuits okay and how can we distinguish them and looking how the 00:01:33
resistances are situated are connected in this industry and we have a serial 00:01:45
circuit if the resistances are connected like this like this okay one and then 00:01:53
another one and then another one okay a parallel circuit it's not this kind of 00:02:05
connection parallel circuit is something like this we have resistances sorry 00:02:14
because some some of you now doesn't know what is this this is a resistance 00:02:21
this is another resistance this is another resistance this line this line 00:02:30
this line are pieces of wire okay come on let's do some resistances I transform 00:02:37
like this okay but you can see both of them okay and this is the wire okay we 00:02:45
have this different connection between resistances and they don't look similar 00:02:58
to this one the how can we distinguish it with a trick thinking about the 00:03:08
intensity intensity is the is like the imagine a motorway motorway is the wire 00:03:19
in electrical circuits in an electrical circuit and the intensity more or less 00:03:29
it's not exact these are there is the the are the cars okay the cars on the 00:03:34
motorway okay so if the intensity comes here the cars yeah all the cars are 00:03:41
going to pass this resistance then all the cars are going to pass all this 00:03:50
resistance and then all the cars are going to pass this resistance okay okay 00:03:57
this is a little bit difficult but in this case all the intensity gets get 00:04:03
this point okay this point and then the intensity must be divided in two ways 00:04:11
one amount of intensity in this way and one amount this way okay so an example I 00:04:22
told you about the cars and motorway this is a motorway and here you have a 00:04:31
cross okay you have a you need to to choose which way way to Mahala on the 00:04:37
way to Madrid okay so some cars are going to take this way and some cars 00:04:46
going to take this way okay so if and then passing this resistance all the 00:04:52
cars from Mahala on the and from Madrid both both get this point okay and then 00:04:59
they go they go together from this point till the end of the wire okay I don't 00:05:08
know if you are understanding me 100% okay but this more like more or less 00:05:18
this okay we have if we don't have if we don't have a split of intensity like 00:05:25
here if all the cars take the same way we have a serial circuit if we have a 00:05:34
division of intensity we have a parallel circuit and what is a mixed circuit so 00:05:42
maybe some of you already know that mix it and a circuit is a combination of 00:05:50
both circuits okay something this is the simplest one 00:05:59
we have another possibility that is as simple as this one okay so in this case 00:06:09
this case all the cars all the cars pass pass by this resistance so this 00:06:21
resistance is serially connected to this second part okay and how are these 00:06:33
two resistances connected and both are parallel okay from here the cars must 00:06:44
must divide the amount of cars I don't know if you understand me okay and we 00:06:54
have all the intensity crossing passing by this resistance but from this point 00:07:02
till this point we have a division of intensity some amount of intensity take 00:07:08
this way and some some amount of intensity take this another way so we 00:07:16
here we have part that is serial and this part is parallel so both together 00:07:20
are a mixed circuit okay more or less I have explained I have explained 00:07:28
everything here you have almost almost I have explained almost everything so what 00:07:40
is missed till now this how to calculate the total resistance of a 00:07:51
circuit this is the most important part and this sometimes is difficult it's 00:07:59
hard for you to do this properly okay so let me do an example 00:08:08
for instance we have this circuit two resistances connected okay not two, three 00:08:16
and here these three resistances as the title of this part says are connected 00:08:29
and serial in a serial way okay serial okay so the value of this resistance is 00:08:40
two this is four this is five this is not okay this is wrong we need the units 00:08:52
which unit which unit do we use to measure resistances this one ohms okay 00:09:02
ohms ohms because of the Greek letter Omega this is Omega okay Omega everything 00:09:11
let me do it again very fast one resistance second resistance and third 00:09:28
resistance okay two ohms four ohms and five ohms okay so if the resistances are 00:09:41
in this way they and they are serial circuit so we use this formula to know 00:09:57
the total value of the resistance so how can we calculate the total value of the 00:10:06
resistance of these three resistances connected just adding one by one two 00:10:11
four and five eleven what 11 ohms that's all okay this could be an example okay 00:10:20
this could be an exercise or an exercise calculate the total resistance of this 00:10:37
circuit so serial circuit serial circuit so we do this okay if the 00:10:43
circuit is parallel we we don't do this in fact this is wrong if in a in a 00:10:53
parallel circuit so it's very important to think before if think before which 00:11:02
circuit is in the exercise okay so and just to finish we're going to do an 00:11:10
exercise with them with a parallel circuit okay 00:11:18
parallel circuit here before yeah so we don't say yeah both are examples of 00:11:22
serial circuits serial circuits okay here we have a battery have a switch 00:11:32
lamp okay both I don't know if you see this both are the same same circuit this 00:11:40
is this circuit is drawn with using symbols and this one with with pictures 00:11:51
of the symbols okay this battery is this okay this is the battery and symbol this 00:12:04
is a switch okay here the switch is open and this is both are lamps lamps 00:12:12
okay okay so let's carry on to to to parallel circuit okay in a parallel 00:12:22
circuit we have this difficult formula okay for I'm going to explain you to to 00:12:36
help you with an easier form okay so we have this example I'm going to use the 00:12:44
easiest one not this three resistances again okay so this resistance I don't 00:12:55
now two ohms this one six ohms and this one 12 ohms okay R1 R2 R3 resistance one resistance 00:13:12
two resistance three are connected this is a parallel circuit because the intensity 00:13:29
comes here the cars go together to this point and then they divide in three parts okay so 00:13:36
how can we calculate the total resistance here how can we calculate this is the hardest 00:13:45
thing probably the hardest hardest thing of the whole year okay how to calculate this 00:13:51
because of the this formula okay so calculate RT we're going to use this formula one over 00:13:59
RT is one over R1 plus one over R2 plus blah blah blah so one over two one over six one 00:14:10
over twelve okay are you following me let these values come from here okay six twelve 00:14:30
okay let's let carry on okay so we need to remember how to do this we need to use we 00:14:46
need only one number here below okay so which is the minimum common multiplier so a minimum is 00:14:58
12 so 12 divided by 2 6 multiplied by 1 6 plus 12 divided by 6 2 here 12 divided by 12 1 so here 00:15:12
we have 6 9 over 12 um is this the total resistance no no no no no no no this is the 00:15:32
most common error most common error okay no RT okay it's not RT this because it's easy I think 00:15:53
it's easy to see we are calculating 1 over RT 1 over RT so 9 over 12 is 1 over RT but I'm asking 00:16:06
you to calculate RT no I'm not asking 1 over RT okay so what we we need to do to swap swap 00:16:20
one over RT so RT over 1 RT is 12 over 9 ohms we can divide this 4 divided by 3 ohms and this 00:16:32
is this is one point three three three three three three okay three I'm not going to use the 00:16:58
symbol of periodic okay this is the value of the total resistance of this parallel circuit okay 00:17:11
let me tell you something when we calculate a parallel circuit always the result must be less 00:17:22
than the lowest value of the resistances here okay we have three resistance values 12 6 2 the result 00:17:34
always has to give less than the lowest value of the resistances if it gives more than any of these 00:17:42
the exercise is already wrong, okay, the cars come here, they are divided, okay, they are divided if they are 00:17:48
divided, the parallel circuit is divided, if the cars are divided, the resistance, let's say the load 00:17:56
of the entire circuit, let's say it is less, I don't know if you understand me, the cars come down a road 00:18:08
here there is a division of roads where the cars can be divided the traffic is going to be reduced 00:18:13
if the traffic is reduced the resistance of the road if you want to understand it is less the traffic 00:18:18
will be less in its set of agreement you have to understand what I say if we only put a resistance 00:18:24
in series because it is good it will give us something else different the trick I explain it in case the 00:18:30
trick is worth for two resistors but it can be expanded for 3 and for 4 for the ones we want 00:18:38
but we always have to do two in two we have for example this value of resistance 2 and 6 00:18:48
for example 26 in parallel how to calculate total resistance if we wanted to do it by the 00:18:53
formula that is up there we can do it but in the direct way we can put rt directly 00:19:00
rt is equal to the product of these two 00:19:06
2 times 6 and between the sum 00:19:13
2 times 6 is 12 00:19:18
and 2 plus 6 is 8 and this would be the value of the total resistance of this circuit but it is only 00:19:21
valid for 2 if we want to do it for 3 we would have to do this parallel first what we are going to do 00:19:29
is this just and the result to make the parallel again with this you understand what I say, that is, 00:19:35
we have just calculated 2 and 6, it gives us 12 octaves that we can divide by 4, it gives us 3 00:19:43
means, not 3 means, which is 1.5, because if now we do 1.5 ohms, the units are important, 00:19:50
because now we do this again but with 1 and 5 1.5 and 12, that is, we multiply 12 by 1.5, we 00:20:00
divide it by 12 plus 1.5, it gives us the same again, try to do it and you will see that it gives you the 00:20:10
same value if it does not give us that or two things or you have done it wrong or you have understood it wrong ok 00:20:17
and nothing else I leave you some exercise to do in relation to this ok I leave you all this 00:20:26
week to do a hug and be careful there will be ok exercises of mixed circuits we are not going to 00:20:32
do ok we are not going to have this course and with this it will be enough 00:20:41
Idioma/s:
es
Autor/es:
Iván PB
Subido por:
Ivan P.
Licencia:
Reconocimiento
Visualizaciones:
6
Fecha:
26 de julio de 2023 - 12:16
Visibilidad:
Clave
Centro:
IES JOSÉ SARAMAGO
Duración:
20′ 47″
Relación de aspecto:
1.78:1
Resolución:
1920x1080 píxeles
Tamaño:
47.78 MBytes

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