Hi Babs. So, this might be a bit of a weird request so feel free to turn it down or ignore it altogether. But.
Could you please explain to me the basics of electricity?
Volts, current, impedance, electrons as packets in time, only entry level stuff, really, just how to think about/conceptualise what the heck is going on with electricity. Ever since high school it's never made any sort of intuitive sense, and it's not that I'm bad at physics (my brain works amazing with classical mechanics, I've got good grips on optics and acoustics, and I THINK I can understand the general shape of the basics of quantum, [ like seeing a murky shadow under the surface of the water and being able to understand that, indeed, water is wet ] ).
But not electricity? I've looked for explanations and videos and asked around irl with people who actually studied hard sciences (I studied film) but I just? Don't get it?? It stumps me in a very frustrating way.
And reading your essay on impedance it made sense, so, if you want to, if you have the time, if it's not a hassle, could you talk to me about electricity and how to think about it?
The Basics of Electricity According to Babs
Electricity tends to mess with people the most when they can't visualize it. IMO, the easiest way to visualize it is to explain things as analogous to water and plumbing effects so we'll start with that.
CURRENT is the rate of electrons going through a wire. It's measured in amps, which are coulombs per second, and a coulomb is just a weirdly specific number of electrons. In water-flow analogies, it's comparable to flow rate, or gallons-per-second.
VOLTAGE is the average energy of the electrons flowing through the wire. In water-flow analogies, volume (gallons) times pressure (PSI) equals energy, therefore volume per second (gallons per second) times pressure (PSI) equals energy per second, which is power. Voltage times current also yields power.
RESISTANCE/IMPEDANCE is defined as the ratio of Voltage to Current that you get in a circuit. To compare that with water, again, think pipes: A very narrow pipe (quarter inch?) that's got 10 PSI of wall pressure will only move a few gallons a minute. A very wide pipe (think, like, 5 feet wide) that's at 10 PSI will move hundreds if not thousands of gallons in the same time. Despite having the same pressure.
There is a slight but realistically important detail that resistance kind of (but not necessarily) implies DC current, while impedance implies AC, and in AC circuits there are some components whose impedance is not as simple as the voltage/current ratio, but also, the frequency of the incoming signal. Which I will explain with the two main reactive circuit quantities.
INDUCTANCE is a system's tendency to intrinsically resist changes in current. There are components that maximize this property that are called inductors. You can broadly think of it as similar to inertia, but in the pipes-and-water analogy, it is highly comparable to something called Water Hammer. Water Hammer is when you have a long length of pipe with high speed water inside it and a valve. And then, if you close your valve too fast, the water doesn't have time to change direction, and it will run into the valve and actually just explode it. The weight and speed of the water can give it momentum comparable to like, trains, and if you try clamping it immediately, the pressure will spike up to insane levels, so you have to turn the valve slow and gentle. Continuing the analogy of pressure equaling voltage, trying to turn a high inductance circuit into an open circuit will result in a huge voltage spike.
CAPACITANCE is a system's tendency to resistance changes in voltage. Again, there are components called capacitors that intentionally perform this task. In the pipe-water analogy, you can just think of them as pressure regulators, or maybe more like literally giant rubber balloons connected to the pipe. They'll inflate to the pressure of the pipe when it turns on, and then just chill afterwards, but if water pressure was ever lost they'd start deflating and pushing water out, keeping pressure mostly stable.
In an AC signal, high frequency noise gets heavily impeded by inductance, while low frequency noise gets heavily impeded by capacitance. To explain why capacitance plays nice with high frequency signal, again, think of a balloon: It's a lot easier to breathe one little breath in, let it out, little breath in, let it out, breath in, let it out, then put five consecutive breaths in. Each breath you put in without letting air out increases the pressure required to put the next breath in, and the next, and that just takes a lot of energy. High frequency signal is like doing a bunch of little hyperventilated mini breaths into a ballon instead of long, deep, hard, consecutive ones. To explain why inductance plays nice with low frequency noise, think of the water hammer: The slower you turn the valve, the less intense the water hammer will be. High frequency signal is like cranking the valve shut as fast as possible.
This is my very condensed Circuits I course. I hope it was enlightening.
tangentwithtanner
stormborns
blakekathryn
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