Current In/Out: Understanding Electrical Circuits

[Lupo]

I am not an educated man, so please try to answer in Layman's terms.
It makes no sense to me. How and Electrical circuit that has X amount of current flowing through it, and X amount of current being used by a Device. I.e. a Washing Machine, Light bulb etc. have the same current flowing out of the Neutral Wire.

If i have 4 Apples going through a Pipe and a Rat eats one Apple. There should only be 3 Apples coming from the end of the Pipe.

 

[russ_watters]

If i have 4 Apples going through a Pipe and a Rat eats one Apple. There should only be 3 Apples coming from the end of the Pipe.

It's more like sawing a piece of wood. The saw moves back and forth through the wood and doesn't get consumed.

Moving to EE.

 

[DaveE]

Think of a water flow analogy. How does a water powered saw mill do the work of cutting logs if the same amount of water flows into the water wheel as flows out of it. The answer is that energy is extracted from the flow (like lower velocity at the exit) not that you used up the water to cut the logs.

Each electron has a force pushing it (voltage, basically). The voltage available at the exit is what is reduced, not the quantity of electrons.

Later on, if you keep studying, you'll learn that water and electricity aren't always so similar. But this is a good analogy for now.

 

[Lupo]

That makes perfect sense. I've always liked the Water analogy, when I got my Electronic Certificate. Often, when we get thought a Subject. We are expected to accept certain Laws without real explanation. That has never appealed to me, I find learning, and retaining what I've learned very hard, unless it makes sense to me. So thank you very much for your answer.

 

[Lupo]

There no fool like an old fool. Haven't done any electronics for many years and forgot the basics. The Voltage drop across a Resistor. I was to consumed about a RCD thinking of current being use instead of Voltage. Of cause the current would stay the same, if it was used in a normal circuit and not leaking to earth. I'll just claim that i have Old timers disease.

 

[sophiecentaur]

@Lupo Think about a bicycle chain. The same number of links are going round all the time. It’s the tension and motion of the chain that transfers the Power from foot to wheel.
The links all find their way back to the chain wheel, again and again.

N.B. But the kinetic energy is a tiny part of the energy transferred. (Links or electrons)

 

[anorlunda]

@Lupo Think about a bicycle chain. The same number of links are going round all the time. It’s the tension an motion of the chain that transfers the Power from foot to wheel.
The links all find their way back to the chain wheel, again and again.

N.B. But the kinetic energy is a tiny part of the energy transferred. (Links or electrons)

Normally, I dislike analogies for this stuff, but I like this analogy. Thanks.

 

[sophiecentaur]

but I like this analogy.

It's an old favourite of mine. If they don't get that one they won't get anything else. It's a thought experiment that anyone can partake of.

 

[sophiecentaur]

Often, when we get thought a Subject. We are expected to accept certain Laws without real explanation.

Either you remember that wrong or the teaching was poor. The 'rules' are only ways or remembering stuff that you should also understand at a reasonable level. Rules don't explain things - they are just easy to apply to a new situation. They often use mathematical formulae in order to be concise but that can bring on the pains for some people but there are no aspects of Physics which are made harder by the use of Maths.

The sort of discussion that you can find on PF can usually be good for clearing up misconceptions but PF is a bit of an exception. Many other forums are full of ignorance and oversimplifications; read them with care. PF is moderated to a high level and can mostly be relied on to get the right message across. (Stick with us, kid!)

 

[artis]

If i have 4 Apples going through a Pipe and a Rat eats one Apple. There should only be 3 Apples coming from the end of the Pipe.

3 apples and an excrement (the latter one might be delayed)
Don't forget the energy and mass conservation laws that even rats abide by!

There no fool like an old fool.

Said the rat in the pipe after it got hit by the first of the 4 apples , that go through the pipe in your analogy

PS. Kudos to you @Lupo I liked your self reflection , made me laugh, have a nice day!