In this entry I'm gonna show how to analyze a circuit, just like the previous one but a little more complicated.
Using the previous circuit, we are going to add an extra resistance behind the original, so we can see what happens with the current and with the voltage.
Current will flow in the same sense as in the first circuit, and the polarities of the resistors will be the same. Remember that the current in a resistor enters the positive and out by the negative but remained always positive, in this case it does not chage the value nor the sense when passing through R1 so that the circuit with their respective polarities would be as shown:
One can see that the current flowing through R2 is equal to the current flowing through R1, so in an electrical circuit the current is the same in two or more series resistors(the resistors in series are those that are connected one after the other).
To solve this circuit, we obtain an equivalent resistance of two resistors. For the analysis of electrical circuits when there are two or more resistors in series we must add all the resistances to obtain the total circuit resistance, as Rt--->R=R1+R2+...+Rn
Once we add R1 to R2 we obtain the value of Rt=24Ohm, and we can replace it in the main equation: I=12V/24Ohm=0,5A
One can see that the current value decreased from the original. The more resistance you have, the current value is going to decrease, as there will be more opposition to the flow of it. To obtain the voltage of each element, we must multiply the value of the current through the resistor.
In the voltage's case, one can see that the voltage is the same in the two resistances, but the voltage was divided from the original, therefore holds that in a series circuit the voltage will be different in each of the elements.