# what’s the difference between current and voltage

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what’s the difference between current and voltage

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Hold your thumb over the end of the garden hose, blocking the water flow. Feel that pressure? That’s voltage. Take your thumb away. See the water flowing out? That’s current (amperage).

As already posted, the standard analogy is that current is the amount of flow and voltage is the “force” behind that flow.

Current is, if you were standing inside a wire, how many electrons would go past you every second. (An ampere is actually the number of *coulombs* of charge that go past you every second, but you can just as well think of it as electrons/second.)

Voltage is the average energy that those electrons have, so it tells you how difficult they’d be to hold back or stop.

Voltage is “how hard” the electricity is trying to move.

Current is how much is actually moving.

Say you have 10 volts, running through a 10 ohm resistor.

Current = Voltage/resistance = 10/10 = 1 amp

Now lets double the resistance, to 20 ohm.

Current= Voltage/resistance= 10/20 = 0.5 amp

You still have 10 volts, so the electricity is trying just as much, but it’s twice as hard for the electricity to go through, so only half as much actually gets through.

Current is how much charge is flowing past a point each second, voltage is how much potential that charge has to do work.

Power is voltage times current, so you can get the same amount of power with high voltage, low current – or high current, low voltage.

High voltage, low current means there isn’t a lot of charge, but it has lots of potential energy. High current, low voltage means there’s lots of charge with low potential energy. Same amount of power, two different ways to get there

If you use water as an analogy to electricity, the pressure of water in a pipe is equivalent to the voltage, and the amout of water flowing through the pipe is equivalent to the current (amperage).

If you aim the output of the pipe at a water wheel you can use the force of the water to do turn the wheel and do something useful. If you have high pressure but a teenie little pipe, it’s not going to get much work done. If you have a big pipe but the water just dribbles out, it’s not going to get much work done. Mutltiplying the two is how you measure power (wattage).