Voltage is a difference of potential between two points. Imagine a waterfall, the higher the potential, the taller the waterfall.

Current is how many electric charges are flowing in a conductor. Imagine a duct with water, the more water in the tube, the higher the current.

Power is current times voltage. Imagine you have water from a waterfall, hitting the paddles of a water mill. The taller the waterfall AND the more water in it, the more force hits the paddle and makes it turn.

Power is a measure of work and is the main characteristic of an electric circuit. For example, a 100 watt light bulb is roughly ten times brighter than a 10 watt light bulb.

Voltage and current are the components of power. Power (in watts) equals voltage (in volts) times current (in amps), or:

P = EI

Where P = Power, E = Volts (E stands for Electromotive Force, another term for voltage), and I = Amps (for some reason).

For example, a light bulb that draws 1 amp at 100 volts, and a light bulb that draws 10 amps at 10 volts, and a light bulb that draws 0.1 amps at 1000 volts, are all 100 watt bulbs and have about the same brightness.

What determines how much current a light bulb (or other simple DC circuit) draws is the voltage applied to it divided by its internal resistance (in ohms). So a 100 ohm light bulb will draw 1 amp when 100 volts is applied to it, and a 1 ohm light bulb will draw 10 amps when 10 volts is applied to it, and so on.

It takes a larger wire to handle more current without overheating, and it takes stronger insulation to handle higher voltage without breaking down and leaking (causing arcing or shocking), so those are important factors in determining whether to get the desired power with high voltage and low current or low voltage and high current or medium voltage and medium current.

Water analogy is an easy way to understand:

Voltage: pressure, how hard the electric charge is being pushed.

Current: volume, how much water is being pushed, the amount of charge.

Power: the end result. How much force the water has when it hits, over time. 12V x 10A for 1 hour = 120Wh. You can also remove the time factor and talk about the moment it’s being measured: 12V x 10A = 120W at that exact moment.

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