I am new to electronics, as I have said, and I would really like to know what the 0V / Ground is. I have seen them on many circuits, and they seem to have confused me because they don't seem to go anywhere. If anyone could explain what it is that would be great... ( Here is a place where I saw one: transistor ) Another thing is Zero Volt Rail? I have looked all over online, and couldn't really find anything that was about that...
Ground is referred to as a zero-voltage reference to a higher potential in a circuit. It can also be seen as the returning point for which current to move toward from the higher potential end (this is subject to debate based on actual electron flow and hole flow but whatever). An analogy would be the height a book is off a surface. If a book was placed on a table, the difference between the book and table's surface would be 0 since the table's surface is the reference (ground). However, if you consider the reference point to be the floor, the difference would be the table's height. In a nutshell, ground is just a reference point. If I say 3 miles to get to the fire station, you will want to know from where. That "where" is your reference point. Same as ground for an electrical circuit. Edit: In a modder's perspective: There are a few posts that deal with giving 7v to fans without the use of resistors, voltage regulators, or anything of that nature. They tie the black wire, ground, to +5v and the red wire to +12v. In this scenario, +5v serves as ground and +12v serves as the higher potential. To the fan, it only sees +7v since +5v is used as a reference point.
It's quite common to draw circuit diagrams with any lines connected directly to the power supply just shown as a short line to the power connector symbol (or an 'earth' symbol in the case of the 0V or 'ground' rail) rather than showing them all connected to each other. Example here. It saves the reader having to trace back along the lines all the way to their source to see what's what. In the example you quoted, the ends of the lines would be a connector to the power supply. It's wrong really to talk of a 'negative' connection unless you really mean it. Many amplifier circuits have three power connections, a positive rail (eg, +12V), a genuine negative rail (eg, -12V), and a ground rail (0V). In a car, if the battery '-' terminal is connected to the chassis as usual, that's a 0V reference, not -12V. A computer ATX power connector already has a -12V rail (blue wire), the black wires are 0V. "Ground is referred to as a zero-voltage reference to a higher potential in a circuit." To any other potential in the circuit.
