gandalf_der_12te@discuss.tchncs.de 3 days ago
when you’re using a sailing ship, you’re not actually using wind to drive, instead you’re using the energy within the wind’s movement, that’s what you’re using to push the ship forward
it’s similar with electricity. the electrons rarely get consumed (exceptions exist, mostly in electrochemistry)
akunohana@piefed.blahaj.zone 3 days ago
Sweet allegory! Thanks! 😊
ChaoticNeutralCzech@feddit.org 3 days ago
I could add to this analogy. Yes, the wind passes from a high-pressure point to a low-pressure one but that’s just direct current. The weather can change, reversing the wind every few minutes (alternating current) and you can still harvest it with a turbine (for example, a lightbulb filament or heater lights up in either polarity) but it wouldn’t help a ship with a basic sail travel to a destination (much like DC motors, it would change direction when polarity is reversed). And then there’s sound, akin to very quick polarity changes where particles never travel very far. It doesn’t carry much energy but the waves travel faster than wind and can be modulated with a signal to carry information. Both wired and wireless electronic communication is kind of like that.
akunohana@piefed.blahaj.zone 3 days ago
Thanks! This reminds me, I’ve just recently read about old oscillators and the cycles, periods and hertz of electric signals. In oscillators, or clocks, that are used in computers, the signal switches between current - no current. Which isn’t the same as switching polarity in AC, but still.
It also reminded me of how insane I find it, that the membranes of speakers - whose vibration is controlled by an electromagnet, if I understand them correctly - are able to vibrate in a fashion that not only makes a sinus wave, but sometimes a complex, intricate mixture of sounds, such as when watching a scene from a movie that has soundtrack, ambient sound, speech, explosions, whathaveyou. How on earth can one membrane do that… A piano commonly needs 88 keys whose combination can produce complex harmonies. Speaker membrane: hold my beer.
ChaoticNeutralCzech@feddit.org 3 days ago
The piano key is plucked and then vibrates at its own natural frequency (plus in practice, higher modes aka harmonics/overtones). Wind instruments are designed to create continuous oscillation from constant flow of air by amplifying reflected waves with incoming air pressure energy (blowing straight into a cylinder won’t work, hence the weird pipe shapes, holes and reeds). Either way, they resonate at their design frequency. So do self-oscillating piezo buzzers. The speaker membrane, ideally, does not have a resonant frequency (responds equally to disturbances at any frequency between 20 Hz and 20 kHz) and needs to be pushed constantly to create sound. Like the membrane of a mechanical phonograph/turntable, the shape of the wave it should create is delivered to it in real time, except electromagnetically. That’s why player pianos need very little data (literal punch cards) to reproduce entire songs as opposed to audio recordings