# Understanding the meaning of a waveform of an alternative current

Let's say we have a simple electronic circuit with an AC power source, a resistor and wire. If the AC source can produce this kind of electric current waveform does the peaks of this waveform corresponding to a particular position to the wire?

No, that is a plot of current vs. time (at least, if I understand what you're asking). In electrical engineering, most of the plots you will see of current or voltage are with respect to time (because that's the dimension we care about).

It's not really possible to have a wire with a varying current along its length (alright, so that might not be technically true, but for the purposes of this discussion let's say it is). Kirchoff's law tells us that the current into a node must be equal to the current out of a node. Pick any point on the wire and let that be our node. Then the current in must be equal to the current out, and therefore the current in a wire must be constant along its length.

It's worth pointing out that this is true for "conventional" cases (low frequencies and well-behaved wires). In the context of very high frequencies, everything falls apart.

• is there a way to produce certain amounts of current at specific locations of the wire? Mar 4, 2016 at 6:17
• What exactly would you be trying to accomplish? In an ideal wire, no, you can't do that. Mar 4, 2016 at 6:17
• I am trying to create a grid with wires and I want to provide current to specific coordinates of this grid. Mar 4, 2016 at 6:20
• Is the grid just wires, or are there other devices involved? It sounds as if you want a matrix of some sort. Mar 4, 2016 at 6:21
• There will be a resistor in every coordinate of the grid. Mar 4, 2016 at 6:24

Like uint128_t's answer says: normally this would represent a plot over time. However it is also possible to imagine this waveform travelling through a conductor (wire) and then the peaks would indeed correspond to a certain position in the conductor, but only at a certain point in time as the wave will be travelling through the conductor. Note that it travels at the speed of light ! This means that for a 300 MHz signal the peaks would be 1 meter apart. Likewise 3000 MHz would give 10 cm. For these kind of frequencies you need special equipment !