The easiest way to think of a simple electric circuit is to compare it to a water analogy. Suppose we have a circuit comprising a battery with a voltage V, a resistor with a resistance R, and some wire linking them as shown below. In this case, from Ohm's law, we know that V=I*R, or I (current) = V/R. This means that if we keep the resistance constant and increase the voltage (also known as the "electric potential," then the current will go up as well. Alternatively, if we keep the voltage constant and increase the resistance, the current will fall.Now suppose we have a tank of water feeding a pipe. Also suppose that the pipe has a constriction in the middle. The amount of water ("the current") flowing through the pipe depends on the height of the water in the tank ("the voltage") and how much the constriction ("the resistor") constricts the flow. If we increase the height of the tank (voltage), more water will flow (current). If we decrease the diameter of the constriction (increase it's "resistance"), then the amount of water flowing will fall.Remember that this is only an analogy.In an ideal world, the main pipe itself would be incredibly smooth and would not impede the flow of the water. In the real world, the pipe will have some "roughness" (like resistance) and it will slow the water a little bit. If the pipe was only 1 foot long, it wouldn't slow the water much. If it was a mile long, it would slow the water a lot, even if we didn't have the constriction in the middle.In the same way, in an ideal world, the wire would be a perfect conductor. In the real world, the wire has a small amount of resistance. One way to think about it is as illustrated below:
In the real world, in addition to the main resistor, we can think of the wire as comprising a lot of small resistors. If we were just talking about a few inches of copper wire, then the resistance of the wire would be negligible compared to the main resistor. Suppose our battery were 10V, and our resistor were 1000 ohms, then if we use a voltmeter, we'd see 10V on one side of the resistor and 0V on the other.Now suppose we remove our resistor and increase the length of the wire to say 10,000 feet. If we were to apply our voltmeter to different points along the wire, starting at the positive terminal of the battery and ending at the negative side of the wire, we would see the voltage gradually fall from 10V to 0V as we progressed along the length of the wire/I hope this helps a little bit.
