If in series combination of resistances the current remains same and the voltage decreases then what is the reason behind that the current remains same and not gets reduced?
Answers
This doubt is raised because of a misconception, probably caused by teachers as well as by text books, particularly those authored/published in non English speaking countries. It is incorrect to state that “ a resistance or resistor offers a resistance to the flow of current”. It is better to state that a resistor produces a voltage drop across it when a current i.e. charges flow through it. This way, there is no cause for any misconception or confusion.
1. A Resistance is a component that produces a voltage drop across it, when a current or charges flow through it.
2. The current flow causes the voltage drop. Let there be no ambiguity in this. Forget about the current being reduced by the resistance. This is misleading and can create unnecessary confusion in the minds of a beginner.
* Now, let us discuss this from a different perspective i.e. charge flow.
1. A voltage source V, whether AC or DC can be considered IDEALLY as a storehouse of infinite charges. However, these charges can flow externally only if a path is provided from one terminal of the source to the other
(A) If a single Resistance is connected across these two terminals, the entire voltage drop will appear across the single resistor and the charges will flow at a rate inversely proportional to the value of the resistance.
(B) If several resistors are connected serially across the voltage source V, the voltage will be shared by the resistances in direct proportion to their individual value. However, the charges will flow through all of them at the same rate because there is no other path.
(C) If several resistances are connected directly across V, the entire voltage drop V will appear across each one of them. However, since there are several paths across V, the current through each path will be different. The value of the current through each path or resistance is inversely proportional to its value.
(D) If several resistors are connected in such a way that some are in series and others in parallel, the voltage drops and current flow will have to be computed based on the above logic.
Electrons are charged bodies with so little mass (protons, with opposing charge, are more than 1800 times greater in mass) that they can be separated from their atoms under the right circumstances. You could get a sense for current if you pictured a wire as a long row of seats, with doors at each end and a person in each seat. When the potential voltage is enough to cause current, by analogy, the doors open, the receptionist becomes a person to enter her door, and a new person enters the other door looking for a seat. Each person sees a seat open, in turn, moving towards the receptionist's door. In this way, every seat sees a person go, and a new person come to sit.
In this analogy, the Receptionist is a positive charge, drawing electron people to her. The other door is the negative terminal of the source, and the movement of electron people is current. It is an imperfect analogy, but closer to what happens, rather than the idea I was originally taught, which said that a single electron goes from the source terminal to the other source terminal.
This is why current is the same at every point in the circuit, simultaneously.
Also, there is only one path for current flow in a series circuit. Because electric charge flows through conductors like marbles in a tube, the rate of flow (marble speed) at any point in the circuit (tube) at any specific point in time must be equal.