How does a resistor cause potential to drop across it?
if you apply an effort to stop / block the flow of current, you apply a force. this force is in turn a voltage drop that results in a loss of heat effect.
plus resistance, plus collision with charge carriers, plus energy drop. this energy drop appears in the form of heat in the resistance. then, the potential will fall through resistance. but through the driver, collisions are minimal, minimizing the fall.
consider the simplest form of a circuit consisting of three resistors in series.
The application of a source voltage basically means that the charges were powered, which made them move around the circuit.
Thus, when the charges begin to move in the loop, suppose a resistance is found, they must invest the energy they had obtained when powering the circuit to overcome the resistance offered.
So when the charge is fighting valiantly through the resistance and coming out the other end, what are you waiting for? Obviously, there will be a decrease in the energy of the load, which will be seen as a potential drop across the resistance.
The resistance of a material is determined by the conductivity or simply says that the movement of the load is smooth.
Thus, when a load must pass through a material, the resistance called or the difficulty caused by its displacement is called resistivity.
So imagine that you are crossing a path and going in the opposite direction to all others, so you are supposed to be responsible and all the others must apply force. Thus, the higher the population density, the more energy you lose while walking. that’s what happens with the charges. for the flow of charges, the potential is applied and it is only the overall energy given to a load. and this charge loses its energy in a resistance cancellation. this loss of energy is a potential fall.
in a conductor, the flow of electrons (that is, the electric current) is the result of valence electrons, or free charge carriers, in the outer orbits of the atoms that make up the atomic structure of the conductor, transferring to the valence layers of the adjacent atoms. the process is analogous to an old-fashioned bucket brigade, where water is transferred between two relatively distant points, in small discrete steps, each person handing a bucket to the person next to him.
in very good conductors (copper, silver, etc.), which have a relatively low resistivity, there is a relatively high density of atoms with free valence electrons / charge carriers, which can be detached from their parent atom allowing them to transfer adjacent atoms to the valence layer, with relatively little energy lost during transfer. in resistors, the density of atoms with free charge carriers is lower and there is a greater atomic distance between the atoms with free charge carriers available, resulting in a greater loss of energy in the process of electron transfer. this lost energy is translated by heat, depending on the current squared and the resistance of the material (1 ^ 2r).
To return to the bucket brigade analogy, increasing the electrical resistance of the material equates to increasing the distance between people holding the buckets – they have to do more physical work between the point where they receive a bucket of a person, and the point where they finally hand over the bucket to the next person online.