V+ and GND
This is very important. In many circuits the most positive point, or the positive terminal of the battery in this case, is called V+. This stands for Voltage Plus, or Voltage Positive. You can pronounce it "vee plus". Likewise, the most negative point, or the negative terminal of the battery in this case, is called Ground, abbreviated GND. Many circuits will label V+ as Vcc ("vee cee cee"). For the most part, these two terms are interchangeable.

Lets look at the symbols for V+ and GND.

Above is the symbol for V+ when we are talking about a 9V source.
The number may change, but we can still call it V+.

Above is the symbol for GND.

This is done to make schematics cleaner and easier to read. Most schematics that you will find will have these abbreviations in them. To make schematics even neater, many people leave out the battery all together and simply draw lines connecting to Vcc and GND. This can really clean up a big schematic where lots of parts connect to Vcc and GND.

Lets take a look at the same schematic that we've been working with drawn with Vcc and GND.

The same circuit drawn with V+ and Gnd.

Notice that this represents the exact same thing. One side of the light bulb is connected to the positive terminal of the battery, and the other side is connected to the negative side of the battery. The light bulb will be on.

So far we have been using a circle with +9V in it to represent a battery. This is actually the symbol for a voltage source. A battery makes a great voltage source, so it is valid to use a battery when you see a voltage source drawn in the schematic. Sometimes a schematic will be drawn with a different symbol to specifically represent the battery. That symbol looks like this.

The same circuit drawn with a battery instead of a voltage source.

This is the official symbol for a battery in a schematic. You will not see it as often as V+ and GND. Notice that it still has +9V next to it. This is designating that a 9V battery is required. Other common voltages are +5V and +12V. When you see those voltages, you need to find an appropriate voltage source, such as a different sized battery.

Take one last chance to look back at all of the schematics and all of the real life implementations in this guide, and keep in mind that all of them describe the exact same thing. They are all correct and valid representations of the exact same electrical connections.

If you have made it this far in the guide, then you are ready to read our next guide, Common Schematic Symbols, where we introduce you to the most common symbols that you will want to be able to recognize.