Can someone explain voltage and current in both series and parallel circuits?

Two things to be clear about when talking circuits;

Current is the rate of flow of charge; it helps to think of it physically as some sort of flow.
Voltage/potential difference is the work done per unit charge across a component; it helps to think of this as a driving force.

So when you say 'each bulb gets dimmer in a series circuit because each bulb gets less current', that's not entirely true - if we're thinking of current as flow, each bulb will have the same current pass through it. What really makes the bulbs dimmer when we add more is that each bulb will have a smaller share of the battery voltage = less driving force across each bulb.

In parallel circuits, when the wire branches, each branch will have the same voltage.. Even though the current has to split and each branch receives less current than in the series circuit, there's still the same driving force across each branch, so there's no dimming.

So far, I know that in a series circuit the current is the same across each component, so bulbs get dimmer in a series circuit because each bulb has less current.

I have also learnt that in a parallel circuit, current is shared between each component running in parallel. What does that mean? Also, when you add more bulbs into a parallel circuit, why dont they get dimmer like they would in a series circuit?

On top of this, can someone also explain how voltage changes in a parallel and series circuit.

Thanks

So in a parallel circuit, each branch has the same voltage (but the "electricity" can only flow down one branch at a time)?

And in a series circuit, the voltage is split between the components? (eg a 9V battery could supply three components with voltage, such as ones with 3V, 4V and 2V? Am I correct about these two?

And how is current split/issued out in both a parallel and series circuit?

For voltage in a parallel circuit the voltage across each branch equals the supply voltage. If a circuit has a supply voltage of 10V and 3 branches are connected, it doesn't matter how many branches are connected the voltage across each 3 branches will equal 10V.

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This is assuming there isn't a component between the source and the branches.

Are you sure ? The voltage across each branch will always equal the supply voltage so why would a component that is not in the branch affect it ? You mind explaining it to me if this is the case ? Thanks.


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Check out example 1 from this link:
http://www.physicsclassroom.com/class/circuits/Lesson-4/Combination-Circuits

Resistors R1 and R4 being where they are means the parallel branches don't have the source voltage across them. The parallel resistors have a series equivalent (1/Rt=1/R2 + 1/R3) so you effectively have the parallel branches as being equivalent to a single resistor in series.

If you're at GCSE level, you don't need to worry about this for your exams but if interested give it a read!

I'll give it a read. I do Scottish Advanced Higher Physics btw. What level you studying or have studied ?


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Ah right, good stuff buddy. You ought to give that a read then. I'm studying Aeronautics at uni.

Nice, my brother is actually applying for aero-mechanical engineering at uni. I myself are applying for naval architecture/marine engineering and also mechanical engineering. How's your course going, you enjoying it ?


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Nice to hear of the interest in Engineering! Go for it, you get to see how all this maths and physics is useful. My course is good but pretty tough.. Loads to do always but I do enjoy it.