# Is a two-element circuit series or parallel?

Is the voltage source in series with the resistor or is the voltage source in parallel with the resistor? If the voltage source is in parallel with the resistor, then why do they share the same current? If the voltage source is in series with the resistor, then why do they share the same voltage?

They are both in series and in parallel, correct?

• I think that's a good way of thinking of it - I've heard people call that series and parallel. Sep 22, 2014 at 17:07
• Does it matter? Is there some way of simplifying it better with that knowledge? I'm curious as to what you gain from knowing if it's in series or parallel. Sep 22, 2014 at 17:18
• @horta I think it's a theoretical question - just like whether 1 is prime or composite. Does it matter? No. Is it good to know? Yes. Is there a correct answer? Maybe. Sep 22, 2014 at 22:33
• @felixphew I was wondering what the op was after exactly, but you definitely make some good points. Sep 23, 2014 at 4:45

A Source & its loads always share the same current & voltage as they are source & loads. We say about parallel/series connection of them separately, not together. That means, we say either two (or more) loads are in series/parallel with each other or, two (or more) sources in series/parallel.

Yes. Your reasoning is correct. They share the same current so they are in series. However, they are also in parallel since they share the same voltage.

Two elements is basically a degenerate case. The current through both elements is identical, so they are in series. The voltages across both elemnts is identical, so they are in parallel. Most circuits consist of a lot more than two elements, though, so in most practical instances the distinction is more obvious.

In my opinion, you are creating the confusion by including the power source as an "element." And thinking an "element" is the same as a load. The configuration terms "series" or "parallel" apply to two or more loads. Since your circuit has only one load, neither term applies.

This is not a series or parallel circuit, because the definition is based off the load, not the wires. You have two wires connecting to only one element. Also, the power source doesn't count as an "element" as you meant.

You have one line like below:

_________________________-

Is this line parallel or perpendicular?
Answer: Neither. You need two lines to determine if it is parallel or perpendicular.

Now, you have two lines:
_________________________-
_________________________-

They are parallel.

Similarly, you need at least two elements in a circuit for it to be parallel or series.

Series:

|_______1_________2________|

Parallel:
|___________1_____________|
|\ __________2____________/