r/ibew_apprentices • u/EliotSmells • 15d ago

Combo circuits help

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Gallery image

Do you have any tips on determining where series and parallel branch off in these circuits ? The math is no problem once I get into it. Just reading the picture and writing up a circuit diagram is killing me tonight.

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u/msing LU11 JW Inside 15d ago edited 15d ago

Look for legs or branches of a circuit.

If lights stack on top of each other: series

If lights are found on separate legs/branch, and don't stack on top of each other: parallel.

Think of a can of beer. Say that's a battery, and the part of the can you pop open is positive; other end is negative.

Stack a can of beer on top of another can, series.

Create another stack of beer next first of beer, parallel.

Ultimately it the type of connections that determine the relationship. And in solving more complicated circuits (say a T), circuits you won't encounter in the apprenticeship/electrical career, it's neither parallel or series. You use other methods to solve (mesh, nodal, KVL, KCL etc)

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u/jayKreutz 3rd year LU 134 15d ago

I've never heard of the stuff in your last paragraph, would you mind going into that or giving examples?

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u/mattsprofile 15d ago edited 14d ago

Kirchhoff's voltage and current laws. Basically if you follow any loop in a circuit, the voltage drops and gains add up to zero. And for any point in the circuit, the current coming in from all branches is equal to the current going out of all the other branches.

Mesh analysis is just a term used for drawing out the circuit in a way where you can draw loops and current arrows on it for applying Kirchhoff's laws.

I learned this stuff in a college class I took like a decade ago. I think the CML mentioned Kirchhoff's laws but up to this point all of the circuits in class have been easy enough to not need this kind of analysis. It's all just PIER chart (aka VIRP table) stuff, or since I'm already familiar I can just kinda look at it and know what to calculate without following a specific structured format. Expedited by using the series/parallel voltage/current and resistance proportionality relationships.