Help me understand electricity.

[Dr. KillGood]

So lets help me understand, by useing water.

Wire = Hose
Capacitor = Bucket
Resistor = Smaller section of hose
Voltage = ????
Amperage = ????
Milliamp = ????
Watts = ????
MAh = ????

Ok so this will make it so I can understand electricity!

[newguy101]

well voltage would be in terms of water pressure.
as for amperage, miliamp and mah(miliamps per hour), thay are all the very closely related. in realtion its how much water you have to push through your hose. there are 1000 miliamps in a amp. so a snes mini that pulls about 500mah and you have a 2aH battery, you can run the system for 4 hours (2000/500=4)(excluding screeen and other things)

[Kurt_]

If you MUST use water...



Wire = Hose
Capacitor = Bucket
Resistor = Smaller section of hose
Voltage = Pressure
Amperage (Current) = Volume of Flow (Current)
Milliamp = a smaller measure of an amp (1/1000 ampere)
Watts = Voltage x Current
MAh = milliamp hour. Hmmm...A measure of how much water a tank (battery) can pump out at a certain volume of water?

Anybody else read that article somewhere in PopSci ("The Tabletop Universe") that stated that the equations for fluid dynamics and black hole light dynamics are exactly the same, except for values (of constants, I'm assuming?) Look it up, quite interesting.

[nitro2k01]

I dislike comparisons between electricity and water because it's not a completely compatible model, and because it starts failing soooo hard when you start talking about AC (Alternating current) rather than DC. (Direct current)

To get an accurate water/electricity analogy, you need to think of the electrical circuit as a closed water loop where no water can leave or enter the system. (The water is just a medium and so are the electrons in the electrical circuit; the total number of electrons in the circuit are the same no matter how big or small the circuit is)

• First off, in my closed water system, what resembles a battery?
  A pump does.
• A pump creates pressure, which resembles voltage. If you fill a pump with water and block the input and output, you'll build a pressure, resembling the voltage of an unconnected battery.
• Just as in the common analogy, the electrical current in a wire resembles the flow of water through a pipe. But since in my analogy, the system is sealed from the external world, the water (current) can go in two directions through a pipe.
• Also just as in the common analogy, a resistor is represented by a thin pipe or hose. A thin pipe will limit the flow of water, no matter which direction it goes through the circuit.
• What about a capacitor? I think of that as a large cavity with a thin membrane in the middle. The membrane is made of a form imaginary kind of rubber which is extermely flexible but does net let water leak through it. So in this analogy, when a capacitor is charged, the membrane is pushed in one direction, and when it's decharged, the membrane pushes water back as it returns to it's neutral state in the middle of the cavity.
• A diode is represented by a valve. They both let the water/current flow in one direction and not the other. (Edit: The word valve might not be accurate. I'll try to find the right word later.)

Other electronic components are more difficult to represent even with this analogy, but for the ones listed above the analogy is fairly accurate. Especially, wattage is hard to represent since flowing water doesn't produce heat in nearly the same extent as an electrical current does.

Image of a capacitor in my analogy:


(Edited 5 or 6 times)

[Skyone]

Maybe you should look into how it actually works instead of thriving off these lame analogies.

[timmeh87]

(Edit: The word valve might not be accurate. I'll try to find the right word later.)

Check valve.

I agree that the water model is pretty lame beyond explaining resistance and perhaps capacitance (I dont agree with the rubber membrane model btw.) What is an inductor in this model?

If you want to actually learn something just start looking up things like electron drift and basic circuit analysis. Kirchoff's laws and all that. Wikipedia.

[nitro2k01]

(Edit: The word valve might not be accurate. I'll try to find the right word later.)

Check valve.

Thanks.

I agree that the water model is pretty lame beyond explaining resistance and perhaps capacitance (I dont agree with the rubber membrane model btw.) What is an inductor in this model?

What do you think is wrong with that membrane model? you would need a quite large cavity and a quite flexible rubber membrane for it to work in "reality". Also, water is much more slow than electricity. Other than that, I'm convinced that this analogy is pretty consistent with electricity. I'm even convinced that given the right components, you could even build simple analogies to some simple electronic circuits using this model. (Even though you'd have to run them much slower than in reality, and the size of the components would be a practical problem) My analogy isn't perfect ny any means, but it's as good as it gets when using water as a medium.
Next problem is to find out an analogy to transistors and transformers.

It's possible to make an analogy for an inductor as well, it's just not as straightforward. In my analogy, an inductor is a turbine hooked up to a heavy metallic cylinder. Because of the mass of the cylinder, it takes some force to give the cylinder an angular momentum. Likewise, once it has an angular momentum, it will keep driving water through the component until the energy in the momentum is used up. In other words, it exhibits a kind of intertia which is analogous that of an inductor.

That explanation will probably scare off most noobs, but should make sense to anyone with some knowledge in engineering or physics. So even if the explanation for the inductor isn't too noob-friendly, it goes to show that it is in fact possible to create a somewhat sound analogy.

If you want to actually learn something just start looking up things like electron drift and basic circuit analysis. Kirchoff's laws and all that. Wikipedia.

Well, I personally know electronics pretty well. But some people seem to be attracted to having a tangible analogy. The reason why I came up with this analogy is because is because there's already an inaccurate water analogy, so I wanted to do it better. Trying to get students to learn the "real thing" is all good, but most of the times it's harder than just smacking the definitions of the laws to their face and saying that's how it is.
Slightly unrelated: I regret that the direction of current was defined as the opposite of the direction of electron movement. I know that the direction of current was defined before electrons were demonstrated experimentally, but if the definition had been changed early on, I think a lot more students would have had an easier time understanding electronics. (One thing less to worry about)