I’m in electrical school and we’re learning about series circuits and I was just randomly thinking about voltage drop across devices and was wondering how does electricity “know” to not have the voltage drop to zero at the first device in a series circuit and to drop the voltage according to its individual value of resistance compared to the total resistance of the circuit and divide it accordingly across every device on the circuit until it reaches zero.
In: Physics
You can use water pipes as an analog. It’s not the same layout as your circuit but if you have a water pipe connected to a source, and the pipe forks into two, with A going really far to a dead end, and B leading to somewhere else, the water will actually flow into both equally at first. When the water in A reaches the dead end, it backs up all the way to the fork, then new water from the source can’t go down A, so it goes down the path of least resistance which is B.
The big difference with electricity is that this happens at near the speed of light. The point is electricity doesn’t know, it tries all paths and favours ones that are easier to go down with a voltage relative to the resistance.
The “voltage” across pipe B is zero because it’s equally backed up all the way to the end (infinite resistance). If you were an ant in pipe A, the pressure would be the same all around you with no clear direction, which means no voltage differential. You can measure this in a real circuit as a voltage blip that quickly settles to near-zero (reality is messy) in the dead end wire as it “figures out” it doesn’t lead anywhere.
Latest Answers