Series circuit or parallel

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Dennis Alwon

Dennis Alwon

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If I have a single circuit that feeds one load is that a parallel circuit or a series circuit? My opinion is it is neither since you can't have a parallel or series circuit with one load. My argument was you can't draw a parallel line with one line nor can you have a series with one number or object.

Also, if you use the resistance formula for a load with a resistance of 10 then for a parallel connection you have 1/1/10 = 10. For a series connection the answer is also 10.

So it is either both a series and parallel connection or neither. What say you... I know-- a silly question but I figured the engineers could take this a few pages...LOL
 
IMO, it is a simple series circuit, in that it forms a single closed loop in which there are only two wires attached to each node. I see no argument whatever for calling it parallel.

If you want to talk instead about loads, it is neither a case of series loads nor a case of parallel loads, since there is only one load.

QED

PS: The logic choppers will notice that all of the following statements are true under prepositional logic:

1. All pairs of loads in the circuit are in parallel.
2. All pairs of loads in the circuit are in series.
3. There are no parallel loads in the circuit.
4. There are no series loads in the circuit.
 
IMO, it is only relevant to speak of series or parallel when a circuit has more than one load. It is not useful to apply one of those terms to a circuit with a single load.
 
retirede said:
IMO, it is only relevant to speak of series or parallel when a circuit has more than one load. It is not useful to apply one of those terms to a circuit with a single load.
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Obviously, this is purely a exercise in thought not practical stuff at all.
 
181127-024 EST

I am with GoldDigger.

For analysis purposes it is a simple series circuit, and the sum of the voltages around the loop is zero. If you cut the single load in two, and only have one loop, then it is still a series circuit with two separate loads in series in the loop.

Can I treat the source and load as a parallel circuit? Sure. I would do that if I wanted to know the impedance of the two together. In other words the impedance of the combination as a two terminal network.

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gar said:
181127-024 EST
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Can I treat the source and load as a parallel circuit? Sure. I would do that if I wanted to know the impedance of the two together. In other words the impedance of the combination as a two terminal network.
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:thumbsup:
Sure, but analyzing the source/load pair as a two terminal network kind of implies that you are ultimately looking for the results of connecting something else to those same two terminals. :lol:
 
181127-2205 EST

Yup.

Is a capacitor and inductor a series or parallel resonant circuit? Depends upon how I drive it. What if I inductively couple to it? In this case I think I will argue for series circuit.

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With a single load, I agree with Dennis that is neither.

But if I had to pick one, I would say that a single load, like a floor lamp on a 15 amp breaker is a parallel circuit. Reason being is that if I plug in one more floor lamp or 15 more floor lamps, it is still a parallel circuit regardless of the number of loads. The circuit nature does not change based on the number of loads.

That said, singular items are almost always different than their plural, at least with the English language. You cannot have one geese or one mice, or one boxes, but you can have one deer. Perhaps a crude or incorrect analogy, but it does go to naming conventions.

I can also see the argument that a single load is a series circuit, since its terminals, or in the case of the aformentioned floor lamp, its plug is in series with the branch circuit conductors, and all other loads are placed in parallel. in that case though, all of the loads are in series with the circuit conductors, but parallel with each other.

I am going with series though, because in the case of a multiwire branch circuit with numerous loads, all wired in parallel, they all act in series if you lose the neutral.

And if you noticed that I have flip-flopped my position from starting sentence to the end, that was intentional.

One more flip flop though, and is applicable to all NEC installations... The branch circuit is wired so that all loads will be in parallel to one another.

So, is a single load on a circuit series or parallel?

Yes:lol:
 
181127-2419 EST

Going back to the original post.

Assume the total circuit is starting at the utility transformer. It can be extended back to the power plant, but I see no purpose for my argument.

Internally the transformer can be considered a voltage source with some series internal impedance. Physically it is clear that the resistive component is the wire in series with the voltage source. Next we get to all the wire to the main panel. Again this is physically a series resistance. More wire from the main panel to a receptacle. Again physically a series resistance. And last the load resistance or whatever. This whole string of things is clearly a series circuit.

Theoretically as an equivalent circuit I can take everything up to the receptacle and replace it with a current source shunted with an equivalent internal resistance. Now I have a parallel circuit. But that is not the physical circuit.

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sameguy said:
And now I have a headache!
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A simple problem is never that simple especially when their are so many great minds working at it.

I still think it is neither a series or parallel connection but if I had to choose I believe I would pick series. Of course, none of this really matters :)

If you draw it out then it looks like a series but I believe it needs more than one to be in a series.

Now what if the load was a light fixture with 3 lamps..... I would say parallel in that case
 
Series = two (E) one (I)
Parallel = two (A) one (E)
Neither of the above can be found with only one load.
 
Source is reference voltage, drops must add to meet reference. Ref. 12v + drop 6v= 18v? or Ref.12v dropa 6v + dropb 6v = 12v.
 
MAC702 said:
This is what I was thinking because in order for it to be a circuit, it would need a power source and a load, and they are in series, even if there is only one of each.
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MAC702 said:
And that's why I say series. You have two (E), one source and one drop.
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One source one drop is purely series flow of current in the entire circuit.

You can have parallel sources and one load or you can have one source and parallel loads - either case you have series and parallel combinations within the loop.
 
181128-1325 EST

There is one closed loop consisting of two items. That is for most purposes a series circuit. The sum of the voltages around that loop is zero. There is only one closed current path, and therefore only one current.

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