We're going to play a game. It's called, find the power source. Ready go:
Okay, maybe that one was little much, try this:
The answer we're looking for here is the 3V Battery.
So what does this have to do with anything? Anyone who has ever have used an electronic device has encountered it. It's where it all begins, simply put, the supply of power. Whether it's a AA battery or a cord that channels the juice from the wall outlet. This symbol is the most important.
|The electronics schematic symbol for a cell|
It's the source of that jumbled mess up top, but it's also in every electronic device you'd come across. Ipods to plasma screens all run on that simple electron (electricity) producing source. The point of all this is that someone sat down with a pen and paper and started with that symbol and worked their way forward, manipulating the electric juice as it flows through the wires.
Using a slew of odd looking components like resistors and integrated circuits, the electrical engineer is the master creator of all things modern.
|An integrated circuit-not a 21st century centipede|
Sadly, the knowledge of electronics seems to be slipping away. It is fair to say we are riding on the backs of a small percentage of the population's intrepid electrical engineers who can take electrons flowing from a battery and turn it into music with a picture of the album.
While the symbol for a cell is the simple drawing of vertical and horizontal lines, there are other sources of power than just a battery (which actually is a combination of several cells).
Others include DC power supplies:
|A representation of DC power-- what comes out of a AA battery|
Or AC power supplies:
|The power that comes out of the outlets|
Both are two different creatures and their behaviors are much different as far handling them in the circuitry. The symbols are not universal, but the idea is consistent throughout schematic drawings. For example look at the first image and notice that its power supply says: " +9 to 12VDC." It just means the juice ranges from 9 volts to 12 volts direct current (DC).