I am reading up on logic circuits, families and levels because it's fun. I have no formal education in physics, computing or electronics.
For power supplies, sometimes one of the supply rails is referred to as ground (abbreviated "GND") โ positive and negative voltages are relative to the ground. In digital electronics, negative voltages are seldom present, and the ground nearly always is the lowest voltage level. In analog electronics (e.g. an audio power amplifier) the ground can be a voltage level between the most positive and most negative voltage level.
I know from previous reading, that electricity - at least when it comes to direct current, but perhaps even when it comes to AC? - has a way in ("line"?) and a way out ("neutral" or "ground"? - disregarding for a second the fact that ground also carries current in case of a ground fault).
Again, from previous reading, I know that we work computers by either supplying them voltage or not (or in some circuits a higher voltage and a lower voltage). In any case, it's a choice between one or the other, since that is what we are trying to represent: boolean true or false.
So, what is this "negative voltage"? Is this a figure of speech or can voltage actually have a negative value? The part from the article that I quoted above states in relativistic terms, that "the ground can be a voltage level between the most positive and most negative voltage level" (italic text by me), which makes me assume "yes". But if voltage is electromotive force, how can it be negative? I amusingly imagine a force "sucking" the current backwards. ๐คญ
Explain it to me as if I was five. ๐ถ
Holy shit that escalated fast! In a fascinating way, that is! Thanks! So, truly, there is a measurable, fluctuating voltage (measured in electron volts) in the ground, but for our everyday appliances we rather measure voltage in the difference between the immediate source's terminals, such as the two terminals of a battery, for instance?
That's my understanding, I think I've grasped at least the general gist of it, if not the specific nuances and details. Granted, I'm not a physicist or scientist of any sort. My dad was an electrician if that counts for anything, I dabble in electronics and I watch a stupid amount of Youtube, but those are pretty much my only qualifications, so feel free to consider this having a similar accuracy and truthiness level to that of generative AI, I won't be offended.