You probably already know that electrical engineers do not draw pictorial
diagrams for every circuit. Instead, they draw symbolic diagrams
that represent a physical situation. Do you remember this circuit?
Now, imagine that the element shown as a
yellow rectangle is a battery. We would draw this circuit as shown
at the right. Notice the symbol for the battery, with the "+" and
"-" signs. Notice also the two elements, shown here as rectangles.
Later, we will examine some symbols for particular elements.
These diagrams may not look like the physical system, but they form a sort
of language that allows precise communication between engineers about exactly
what comprises a particular circuit. Different kinds of electrical
elements have different symbols. Sometimes new symbols have to be
invented when someone invents a new electrical device.
Here are some symbols that are used for some common components.
