This may just be me not having a degree in electrical engineering or electronics, but the whole notion of "ground" and "earth", when used in electrical circuit diagrams (especially integrated circuits), is extremely confusing. I guess the whole notion of current "comming from" the positive terminal (which is often how current seems to be described) seems backwards and misleading to me, given the quantum mechanical description of electrical current as the flow of electrons. So, I'd just like to clear up my understanding of things.
First things first...to make sure my understanding of voltage and current is correct. Assuming a direct current context (I understand things are more complex when using alternating current, and I understand that it is possible to have ground at a positive terminal in some systems and things like that.)
A. The positive terminal in a circuit is what creates voltage. Voltage is a potential, so given that it is the positive ions in, say, a battery, which are generally fixed in place, it makes sense that the + terminal in a circuit would create voltage.
B. The negative terminal in a circuit is what provides current. Current is the flow of electrons, and that flow is towards the terminal that is creating the potential for current.
Assuming these statements are true...then why is the term "ground" (primarily) or sometimes the symbol for "earth" used so extensively in electrical circuit diagrams? Why is it ground or earth, rather than just a negative terminal, or a 0V terminal, or maybe just a "common" terminal? The use of ground or the earth symbol, particularly in IC circuit diagrams (which are not necessarily used in circuitry that is even remotely capable of being "grounded" to the earth...such as in an airplane or a spacecraft, or even any number of isolated, insulated systems that cannot be directly connected to the earth), is extremely confusing to me.
Is this just some old convention that hasn't ever been broken? Is ground (the GND terminal) or the earth symbol in a circuit diagram just a thing that's done, because that is always how it's done? Because that's how it's always been taught? Does it really just mean a negative terminal, or a terminal from which electrons flow? When is the use of a literal ground, a point where a circuit actually connects to the literal earth, actually required? It seems clear that not every circuit, like an IC, does not actually need a literal connection to the earth in order to function.
Well, sorry if this is an odd question, however as I play more and more with electronics, and since I'm powering most of my little projects with batteries, this whole concept seems odd and confusing to me...there is no literal "ground" or "earth" involved in the circuit. Only the battery terminals and electronic parts.
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