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In the previous example we had been in a series configuration circuit with the following resistors
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we have a black orange brown resistor that is equivalent to 10 thousand or mine or 10 kilos
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we have a brown resistor in the red red that indicates 1200 or 1.2 kilos
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we have a green one blue red which is equivalent to
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5.6 kilos
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here we can clearly see the three resistances the way they have been connected
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we are going to do a small calculation
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to find the total resistance and each of its voltages then we have the 10k one the
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1200 one and the
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5.6 kilometer one
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Before doing the respective calculations
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we need a voltage source in my case I have a small source you can have
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a cell a charger a battery let's look at what voltage this source has
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we learn our multimeter our multimeter should be on the scale the black tip where it says com
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and the red tip where it says b
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we go to the symbol where it says be and a little line in some cases it comes like this, for example it says
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b for co for cb
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with
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three lines
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and this symbol,
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any of them indicates that it is direct voltage
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or continuous voltage in my case This multimeter has this symbol, as we can see, here
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we go and we are on the 20 volt scale.
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In my case, my multimeter says that it is ago, so
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I pressed this little button and it will tell me that it is CE voltage.
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Not all multimeters
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have the condition of activating. dc or does,
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that is, this multimeter measures alternating voltage and continuous voltage on the same scale. I am going to tell you another multimeter.
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For example, this one,
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here we have the scale
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only of 6 and down here we have the scale only does
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with any of them that we do. the measurement the result will be the same the first thing we must do is
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measure the voltage of the power source that we are going to feed into our circuit to do the calculations
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we place the red tip
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on the red wire and the black tip on the nest wire
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it says that It has 4
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97 volts that will be the voltage of my source. Let's check it with the other multimeter.
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Let's see if it is approximately the same voltage.
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We put it on the scale of 20
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and make the same measurement.
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In this club it reads
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495 or so.
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So that differs. It depends on the multimeter, the quality, the resolution or the battery that the multimeter has.
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With 497, they tell us the following.
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Our calculation
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will mean that we have a source of
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4.97 volts.
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This will be our source. Now we are going to find the
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total resistance. The total resistance. We had already said that It is the sum of the
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resistances and as such they must be added in the same units as we have 10 kilos,
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sorry as we have resistances in kilos we are going to add them in kilos although if we want we can also add them in
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obvious
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design character
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these symbols 1.2 k it is always recommended to do the following
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1 k 2
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telling us the k the point why this is due when you take plans you make
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photocopies at
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different times of the same plan the point tends to get lost therefore
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you would no longer understand 1.2 almost no 12 k and that is something very important in a design so
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get used to having 1 k 2 which would mean 1.2 kilometers
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doing the respective sum we would have the following value we would have 10 k
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+ 1.2
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+
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5.6 kilos
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that gives us a total resistance of 16 to 8
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kilos omnium
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that in the previous practice we had also already verified it
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approximately then to measure resistances it is always done without a source, it should not be placed because otherwise
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we can damage our multimeter, remember that the multimeter I know generates enough voltage and current to measure the resistance total
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of our circuit well here we have our multimeter we go to the omnium scale
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according to our calculations of truth 16.8 that is to say that on the 20 kilo scale
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I can perfectly measure my resistance
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so
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we take from end to end
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16.8 kilo or less it should measure so we take
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and We place it
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and the
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16.55 kilos are
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approximately the theoretical value
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Because it differs due to the tolerance of each of the resistors, remember that they are 5% because they are all gold.
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Now what we are going to do is measure each of the voltages,
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for example, more or less than one plus less than two
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plus less than three and we are going to measure the total current of our circuit
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as we already know that the total residence of
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16.8 kilo theoretical news we are going to continue working with that value we have 4
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97 volts and a total resistance of
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16.8 kilo total omnium what we must do is make the division
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divide
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4.97 divided by 16 thousand
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800 men
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then the total iv is equal to the source voltage divided by 16 thousand 800 volts
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are always recommended
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over UFOs in this case here it would be 4
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97 volts divided by omnium the result will be
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amperes as we can see
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there I was putting the voltage
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this result in the calculator
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we give it shift engineering
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and it gives us
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and total is equal to
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0.29
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thousand amperes
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So that is the Total current
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of my circuit
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or I can also have it for example shift ng chip on axis until here it appears in zero and we can observe the value
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in amperes of our of our current then of
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0.30
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29
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amperes
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with those values
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that is to say with that current this current means that it is the one that circulates through the entire circuit or through each of the
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resistive components this same current circulates
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Now we are going to look theoretically and practically at what voltage they are going to give us. Everything, first of all, what we are going to do is
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b1 b1 is equal to the y total times ere 1 b 2 is equal to the y total times ere 2
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b 3 is equal to the and total for ere 3
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being r 1 10,000
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Being
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2200
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and being r3 5600 years times amperes
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it will give us volts so here we have 29 amperes and the result it gives us will be volts
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times
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0.000 29 amperes because it is point 000 29 amperes
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Let's check
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and finally we have
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1.65 volts
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what I did was multiply the total current which is the same because it is a single loop
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multiplied by each of its resistances
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we are going to practically check those values the first thing we must do is power our circuit
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To power In our circuit, in this case there is no problem where we place
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the positive or negative polarity. We simply place it at the ends.
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We take our multimeter on the volt scale.
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We place it on the scale of 20
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and we are going to make the respective measurement of the voltage of each of the resistors
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theoretically says that b 1 is equal to
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2.9 volts, let's check if that value is correct, then the first resistor disc at
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2.9
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Effectively
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292,
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the second resistor says that it should give more or less 0
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34, the value is approximate depending on the quantity of decimals that they use then we place
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0
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35
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Perfectly and finally it says that it is 1.65
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1.64
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how to measure voltage the voltage is measured
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by connecting the ends of the source on the resistance and on each of the components
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I must measure the voltage
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so I measure like this one by one here
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here and here I must not disconnect anything to make the measurement
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we are now going to measure the total current the total current says that it gives me
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0.3 02 29 amperes or 0 29 milliamps
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or it would also be 290 micro amperes to measure the current if necessary Disconnect
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one of the main cables from the source. In this case, because it is series, we are going to measure the total current, even if
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we disconnect any part, the current will always matter to us.
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In this case, we have to be very careful with these multimeters because we have to change the tip.
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We change it here to measure current. The current is measured in sed and volt in parallel.
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Voltage in parallel means
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component by component and current in series. It means disconnecting and placing the leads of my multimeter in series with circuit
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2. We place ourselves on the current scale.
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here it says one and with this small symbol and we are located at the highest scale which is 200 m here we also have
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ac current and that current in this case ce current you can connect this negative cable so we connect the
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cable here and the other the other end where they disconnect
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It measures 0.2 it means that I can go down a little more on the scale of 2000
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It measures
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0.296
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periods according to our calculations It gave us 0 point
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209 0 points
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0.29 milliamps
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we confirm again
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0.29 correct if I change the tips, for example the other way around
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The average negative current
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negative currents there are no negative voltages as there usually are none,
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what happens is that the tips of my multimeter They are backwards,
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this is the reason why it is marking me with a negative value.
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For example, if it says that the series circuit is the current is the same, then we disconnect here,
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here I am going to disconnect, for example, I disconnect the resistor, I am going to place it down here.
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and where I
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disconnected that is where I should measure, then I placed this point at the top and this point I placed at the bottom
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and as you can see, I can measure the same current
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in a series circuit. Let's remember the three fundamental properties,
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first the source voltage
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is divided by each component the sum of the resistances in the total resistance
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and the current is the same in any part of the circuit
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cause current at the same voltage is divided the resistances are added
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with this we finish the practical part of series circuits No matter how many
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resistors you have, the principle will always be the same based on Ohm's law,
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always remember Ohm's law, that is, b is equal to I times r.
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What I did in the exercise was first.
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find total resistance with the total resistance of I found total current and with the total current I found each of two voltages
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I hope you liked this little video in the next video we will talk about parallel circuits and mixed circuits bye bye