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 controlling the flow of electrons in an eectron tube 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 secndary winding).
Plus, both fields can oscillate 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).
akunohana@piefed.blahaj.zone 2 days ago
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?
brendansimms@lemmy.world 2 days ago
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.
ChaoticNeutralCzech@feddit.org 2 days ago
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.