The high resistance piece of wire in incandescent light bulbs glows as a result of electrons incoming through a low resistance material being squeezed through (bombard electrons that don’t want to be moved in) the high resistance material with a certain pressure (voltage). We are using the high resistance material to usurp (convert into heat and then into light) the kinetic energy of the electrons in the low resistance material (commonly copper wire).
We do the same thing with electrical heating elements and microphones.
Are we also doing this in electrical appliances from which we don’t expect a certain “end product” (heat, light, sound)? For instance, computers. When we were still using actual physical relays to build logic gates, I can imaging electron flow being converted into the energy (eletrco magnetism?) required to actuate/move the switch inside the relay. But what about today’s transistors? The processing units inside CPUs and GPUs heat up, but that’s a side effect of something I don’t understand. We are not trying to reap that heat. We are after manipulating groups transistors into expressing boolean logic by either giving them a voltage or not.
I know very little of electricity, so please do correct any incorrect assumptions! I’m very eager to learn! 😊💡
electron flow is not what transmits energy it’s the electrical field. in AC circuits electrons don’t really get transported from a source to a destination.
the water allegory unfortunately breaks down very quickly. pressure is force per area. voltage is a difference in potential (~charge).
i feel like someone might be better to really answer to your questions. my physics ed is … long gone.
edit: ofc electrical currents (flow/wiggeling) heat up materials through interaction with it. so yeah electrons transmit the energy they get to tge materials.
transistors (and diodes) are black magic to me. i learned to calculate, but never understood the how and why. you might wanna have a look into the avalanche effect, that is at play in a transistor switching. its a good rabbithole for a weekend, i promise!
This is actually incorrect as well, and I’m annoyed at veritasium for this persistent misconception. The flow of electricity is the movement of charge, which is conveyed by the electron. This is what creates the electromotive force, and what does work.
hm thanks for pointing that out. i will have to thonk abt that for longer though.
It’s admittedly confusing because electromagnetism is a unified field theory, and like I said, a bunch of pop-science YouTubers really make it worse. Current is defined as the rate of charge flow through a cross sectional surface of a conductor, which is caused by the electromotive force, which is simply a charge potential. The fields created by moving charge can be used to do work proportional to the current which creates them, but it is fundamentally the current doing the work.
The misconception is that it’s not like one electron zooming down a wire, dumping energy into a sink, but the bulk change in how electrons, and therefore charge is distributed which moves energy around. Think about pushing something with a stick - the atoms near your hand don’t actually need to move down the stick to transmit force.
Thanks! So it isn’t the electrons alone that we make use of, but the electric field that their tiny movements generate?
There’s a HUGE number of electrons in everything with a massive total negative electric charge but almost exactly balanced by protons. That’s why electrons move very slowly in a conductor but still transmit lots of current (electric charge over time).
Accumulating charge in a place is what charging a capacitor or battery is, it creates voltage (potential difference). Charges in an electric field store energy but also their presence/absence can represent data (DRAM and flash memory) and the field has various effects we can use, such as deflecting the beam in a CRT oscilloscope or controlling a stronger flow of electrons in a vacuum tube (valve) or field-effect transistor.
And the current also creates magnetic field with some similar effects (deflecting the beam in a TV CRT) and some different ones (attracting magnets in a motor, inducing current in a transformer’s secondary winding).
Plus, both fields can oscillate at a vast range of freequencies and travel in waves, making radio, microwave ovens, vision, UV sterilization, X-ray machines etc. possible (although each of these applications uses the properties of EM waves at specific frequencies differently).
Thank you for the great examples! See, this is yet another misconception that I picked up at elementary school: that “electricity travels at the speed of light”. After having read all the comments, yours included, and done some more reading, it is obvious that it’s the effect of electricity that to us seems immediate - for instance, a light bulb turning on. The propagation of the electromagnetic fields is what’s fast. Am I right?
Yep electrons travel at VERY different speeds through different materials. For instance, in certain semiconductors they can travel millions of times faster than in copper wire, which is why they are used for power amplification. But even in those, a single electron does not travel very far, relative to the distance we transport ‘electricity’ through wires and such.
Yup. When you add an electron to one end of a wire, the change in the electric field will be felt very quickly (high percentage of light speed) across the wire and the electrons, now outnumbering protons, will repulse and want to shed the extra one from any point in the wire.
Like when you add an atom to a sealed gas container.
I mean, to be fair the water pipe analogy is pretty good as the pressure performs work done per unit volume, and voltage is work done per unit charge which takes up a specific volume of the wire.
But you’re right, with A.C. that analogy gets complicated unless supposedly you had water going back and forth in the pipe, but that is still transmitting energy like a wave does.
like any good model it has it’s scope. inductivity and capacity are out of scope. electrical current is not electrons pushing each other as a longitudinal wave in water could make it wiggle in a pipe. as soon as something stops to make sense in the model we need a new model.
I always see analogies as effective at their chosen level of resolution (similar to your scale).
At dinner-table-conversation level, or 5 year old kid level, these water analogies work.
If you need to actually produce something, they’re completely useless.
But for most stuff/people, Newtonian analogies work surprisingly well, so long as we always qualify it with “remember, this isn’t actually how it works, this is just an analogy to get you closer to how it works”.