What is Voltage? What is Current?

[moklo]

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Gusto lang ko ma sayud unsa jud!

[Pi2plank]

to make things easier, try substituting electricity flowing in the wires by water flowing through pipes... now voltage would be how fast the water would flow thru the pipes (pressure) & current would be how much water is flowing thru the pipes.. mao ni gi tudlo sa teacher namo para sayon sabton..

[karwren]

Actually, voltage would be like the amount of potential water pressure that's available in, say, a tank on the roof: it's the difference between the pressure of a roof tank's water with respect to the ground vs. water that's already just laying on the ground in a puddle, which has zero potential pressure. Another name for voltage is potential. In electricity it's the amount of potential that's measured between a power source and a constant, usually but not always ground.

Current is like the rate of flow through a water pipe of a certain diameter, once you've actually turned on the tap, or completed an electrical circuit by flipping a switch on.

Another factor is resistance. This is like the restriction on the rate of flow due to the diameter of the pipes. A smaller-diameter pipe restricts the amount of water, in liters per minute, that can flow through it as compared to a larger pipe. That's resistance. Wires work the same way: thicker wires can handle a larger amount of current than thinner wires can.

Voltage, current and resistance are related, as the formula of Ohm's Law states: E=I*R, where E means voltage (from "electromotive force", yet another name for voltage- you gotta love those crazy engineers, hehe), I means current (I'm not sure why I, but C is already used to mean capacitance), and R happily means resistance- at least one of the symbols in the formula makes sense. So if you know any two values you can easily compute the third using just basic arithmetic: I=E/R, R=E/I, E=I*R.

[motterj]

(Whoops, that was me that posted the above. I didn't notice that my wife was still logged in, hehe)

[hizuka007]

electrivity is the result of moving/flowing electrons

so,
voltage = ang kakusgun sa pagmove sa mga electrons.
current = ang kadaghanun sa electrons nga nagflow per seconds (?)

[fritzd]

motterj, karwren, nice... hehehe!

Anyway, the answers are more than correct. I'd like to add a small detail which you might find interesting. At a smaller scale, or shall we say from the most fundamental aspect of Current and Voltage. >> Current is the amount of charge carriers (in this case electrons) flowing per time hence its unit is Coulomb(unit of charge) per seconds which is equivalent to Amperes (common unit of current). While voltage, as karwren and motterj pointed out, due to the potential energy difference, it is the Energy carried per charge carrier (electron).

[grovestreet]

naa unta tay "science questions" nga thread... pareha sa kang soul doctor sa S & O nga category ba... naa sila "questions about life". hehehe

[moklo]

naa unta tay "science questions" nga thread... pareha sa kang soul doctor sa S & O nga category ba... naa sila "questions about life". hehehe

mas ok na bro!

[rodsky]

Great thread, guys, keep it going.

I always thought that the mA reading of batteries pertained to a sort of "pressure", whereby the higher the mA, the higher this "pressure" of the current flowing. Is this correct?

-RODION

[fritzd]

Hello Sir rods... If you look closely sa mga batteries, they are written mAH.. It's milliampere hours. Its a like an engineering measure amount of electrical charge stored. If you do a dimensional analysis of the units of mAH, you get (coulombs per seconds) times (hours, which you can convert to seconds), The results will be simply coulombs which is charge. The bigger mAH, the more energy capacity the battery has.

Anyway, if you the mA you saw, was just really mA, then its the maximum current draw possible. Some people want this to be very very large for their rechargeable batteries like people from airsoft guys or radio controlled car racers because they want the maximum power out of their batteries and don't care about long lasting. While for normal people like us, who only use rechargeable batteries for daily devices, we need a battery with respectively moderate mA reading because high mA batteries tend to drain faster. hehehe