Why electricity flows

Im electrical engineer so i guess it was only matter of time before i explored this forum. Here I describe an explanation for why electricity flows in a circuit. The talk explains the concepts of Voltage, Electric Current and Resistance in a electric circuit.


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Voltage is an electrical form of pressure and to understand this concept in the easiest of way is done by
considering its analogy to a fluid system. A simple form of fluid system is found in a rainwater tank. The Pressure inside the tank is greater than the ambient atmospheric pressure surrounding the tank. To release water from the tank into the external environment is controlled by opening a tap on the tank. The flow of water in this manner is analogous to the flow of current. The current flow is commonly referred in everyday terms as electricity.

The flow of electricity is an effect caused by electrical pressure of voltage. To increase the magnitude effect of the flow in electricity (electric current) requires increasing the voltage pressure. The analogy in the fluid system for this is where a tank reservoir is filled with a high fluild level; and possess a greater head of pressure than if the tank level is low.

In a water fluid system the tank pressure is the driving source for the force which pushes the water fluid out of the tap when opened. In the same characteristic manner for an electrical system the electric current flows from a point of high voltage potential to one of low voltage potential in a electric circuit.

The analogy of the water fluid system reveals that electric current is flowing/moving in a direction determined by the fall/drop in voltage potential.

The use of the term Voltage potential is interchangeable with terms Voltage Gradient and Voltage differential and Voltage drop.

The units of Volts are Electro-motive force. Electro simply means electrical energy. The terms motive indicates motion; and force is an effect caused by pressure of voltage as explained in the analogy above. Therefore think of Volts as electrical pressure.

The flow of electricity (electric) current cause by the electrical pressure of the voltage is referred to as in its units of measurement are amperes.

The basic relation ship between Voltage and Current is defined in what is called Ohms law. Mathematically Ohms law defines Voltage = Current x Resistance ( V = IxR). The (x) symbol is a mathematical multiplier like 2 x 2 = 4 for example.

To explain Resistance I will go back to the analogy to a fluid system and a rainwater tank. Imagine now that a hose is connected to the outlet tap on the tank. When the tap opened the water will flow from the tank via the tap and through the hose. The hose itself is physical a Resistance element in the flow path of the fluid; in that it slows down the rate of fluids flow from the tap. Without the hose connected to the tap the water fluid flows out of the tap at a faster rate compared to it the hose is connected.


Therefore Resistance is what limits the electric current flow for a given voltage. The implications of this constraint can be understood for the layman in practical terms by considering the example of a fixed voltage source available from a home wall power socket. The wall socket may be used to connect various electrical appliances. These could be a toaster, TV, computer, electric kettle or hot iron. Each of these appliances have a different value of resistance. The lower the resistance the more current will flow through the electrical circuit within the appliance. A hot iron is the best example as because altering the temperature control has the actual result of altering the resistance in the circuit.

This brings to attention the last term Power. Electric current flowing in a resistive element produces heat which is Power. Yes Power = Heat.

The mathematical formula for Power heat generated in a purely resistance circuit, P = V x I. I say purely because in actually reality applicances such as TV, Washing machines and Radios will also have inductive and capacitive circuits. These I will cover in separate discussion later.

reply to post by AthlonSavage


Yes it flows in certain manners...but what is it?,And why do we love it?....I probably have enough flowing through me to re-charge my blackberry.I'm fascinated just as you are with passion....try a pineal snap,you'll love it.

reply to post by AthlonSavage


amps kill, volts hurt

electreicty itself has always made me wonder, wtf, even after i took electronic principles in school.

Hence, an "electron" can be stretched to any desirable "size." Quantum scale is best described as - velocity and range of positions (possibilities) in my view.

Post

Our reality is merely the resistance (or radiation) of a single point. Reality is the center at which matter churns itself inside the vortex. Traditionally speaking time/ motion does not exist. It's an assembly/reassembly from one center to the next. We are static in particle form while the entire Universe is kinetic in nature.

Source

image. Mathematics . the point or set of points in the range corresponding to a designated point in the domain of a given function.



Also called frontier. Mathematics . the collection of all points of a given set having the property that every neighborhood of each point contains points in the set and in the complement of the set.

Thread


Congratulations in advance...

I need a simpler explanation. One I can understand. Water is a good parallel. I look at voltage as the size of the river bed. And currennt as the amount of water flowing in it. You can have Grand canyon sized river beds (thousands of volt "potential") and only a trickle of current running through it.

The size of the river bed compares to the size of the wire. Thick wire can hold a lot of "current" the same way a river bed can hold a lot of rushing water. Thin wire or small stream bed can over flow (or melt the wire). Either can contain a trickle.

Voltage is the size of the river bed and current is the amount of water flowing thru it. Big river beds can hold a lot of current even if there is only currently a trickle.

Does that make sense?

reply to post by intrptr

Voltage is the size of the river bed and current is the amount of water flowing thru it. Big river beds can hold a lot of current even if there is only currently a trickle.

The thin trickle is due to high resistance in the path. A smaller diameter wire will have greater resistance than a larger diameter wire. Two much voltage pressure applied on a high resistance will generate huge heat and cause premature failure of the resistor. The analogy would be like the wall of a damn holding a reserviour of water and then seeing cracks forming in its wall, a sign its about to break open.

reply to post by AthlonSavage

I have a question. "Electricity" (electrons) flow to ground, right? So how come (it) "flows" out the negative terminal through a light bulb and back to the positive side of a battery? Or does it?

reply to post by intrptr

I have a question. "Electricity" (electrons) flow to ground, right? So how come (it) "flows" out the negative terminal through a light bulb and back to the positive side of a battery? Or does it?

In circuit analysis Current is indicated as flowing source to ground. The actual electrons are moving in opposite direction to the flow of the current. Light bulbs are powered by single phase AC current.

AC current is a sinusoidal wave worm. The term Direct current is not Sinusoidal. DC is derived from battery sources.

AC from power lines is drived by from Power station Generators.

Ground is referred to as the potential of earth. So in home applicances being powered by two phases, one phase can be tied to earth which is done for reason of safety to prevent a potential difference developing between the AC power supply to earth. Such a potential developing can present a personnel electric shock hazard or damage circuit.

This is very cool athlon,
By all means, please keep going......building industry girl here, and all ears
s & f

reply to post by AussieAmandaC


Thanks Amanda. Whats S/F mean?

reply to post by AthlonSavage

um....star and flag

For another thread I came across a series of videos recorded in 2001 about the standard electrodynamics, the U-1 model, or standard group symmetry electrodynamics. It is pointed out that the model assumes a flat spacetime/local spacetime, and that this was falsified by general relativity, and that it also assumes no net interaction with the active vacuum, which was also falsified in physics. The recommendation is that the standard electrodynamics is badly in need of an overhaul:

While I am no genius, I am no idiot either. Thus, I have mastered electricity with 1 simple step: I call an electrician.

I do a lot of handywork on rental properties. I do drywall, carpet, minor plumbing, cement.....but i draw my limit at electrical.

Even on Minecraft.....i suck with redstone circuits.

Great job!

Hell no, volts don't flow!
Potential, ppl........potential


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reply to post by AthlonSavage

Light bulbs are powered by single phase AC current.

Sorry, I should have said a dc bulb. I thought the stipulation of a battery was sufficient. Direct Current thru a "filament" in a bulb and back into the + side of a battery. Which way are the electrons moving? What "lights" the bulb?

Thanks again.

reply to post by AthlonSavage

Yes the water analogy is a very good one. Like any analogy it runs into limitations but it does help provide counterparts we can visualize, like pressure being analogous to voltage.

This thread is much better than a lot of stuff that gets posted here. Thanks for contributing.

Originally posted by intrptr
Direct Current thru a "filament" in a bulb and back into the + side of a battery. Which way are the electrons moving?

I thought he already answered that very clearly. Re-read his answer.

What "lights" the bulb?

It depends on the type of bulb. In an incandescent bulb, electrons bumping into molecules as they move through the filament heats the molecules and when they get hot, they radiate energy in the form of photons (light). Fluorescent and LED lights don't depend on getting a filament very hot to produce light, and that's why they are more efficient.

Originally posted by Mary Rose
The recommendation is that the standard electrodynamics is badly in need of an overhaul:

Even if that was true and I'm not saying it is, that seems outside the scope of this thread, at least so far.
Here you have a chance to learn something, maybe you should try that instead of claiming everything you don't even begin to understand is wrong. After all, the computer you're using to post, and the internet was designed using these ideas, and since I can see your post, they can't be completely wrong...your computer and the internet seems to be working just fine.

reply to post by AthlonSavage


I wish you were my instructor when I took electronics in the military.
Thanks for taking the initiative to post it.

How does electricity actually flow through a copper wire? does the (-) remove an electron and make the (+) advance? I remember back in my electrical years this debate.

CMS

How fast is it?

Serious q??!!

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as in, it acts instantly, you recieve it instantly, and it can be cut off instantly.

is it like a long tube full of little balls, each one push along just a little bit at one end, should instantly push the one at the other end of the tube. instantly, but very slow?

or?

so how fast is electricity??

I would say that this is more of a guide of how electricity flows than why electricity flows.

If i remember correctly you can only have a set amount of electrons in atoms of certain elements. If you add an electron to an atom that already has the correct number of electrons then it tries to get rid of the extra electron by passing it on to the next atom. I think also if you take one electron away from an atom then it tries to steal an electron from another atom. Either way its the passing of excessive amounts of electrons that makes up the flow of electricity.