Unformatted text preview: OHM'S LAW, POWER,
. Understand the importance of Ohm's law and how
to apply it to a variety of situations.
Be able to plot Ohm's law and understand how to
"read" a graphical plot of voltage versus current.
. Become aware of the differences between power
and energy levels and how to solve for each.
Understand the power and energy flow of a
system, including how the flow affects the
efficiency of operation.
Become aware of the operation of a variety of
fuses and circuit breakers and where each is
Now that the three important quantities of an electric circuit have been introduced, this chapter
reveals how they are interrelated. The most important equation in the study of electric circuits
is introduced, and various other equations that allow us to find power and energy levels are
discussed in detail. It is the first chapter where we tie things together and develop a feeling for
the way an electric circuit behaves and what affects its response. For the first time, the data
provided on the labels of household appliances and the manner in which your electric bill is
calculated will have some meaning. It is indeed a chapter that should open your eyes to a wide
array of past experiences with electrical systems.
4.2 OHM'S LAW
As mentioned above, the first equation to be described is without question one of the most
important to be learned in this field. It is not particularly difficult mathematically, but it is
very powerful because it can be applied to any network in any time frame. That is, it is ap-
plicable to de circuits, ac circuits, digital and microwave circuits, and, in fact, any type of ap-
plied signal. In addition, it can be applied over a period of time or for instantaneous
responses. The equation can be derived directly from the following basic equation for all
Every conversion of energy from one form to another can be related to this equation. In
electric circuits, the effect we are trying to establish is the flow of charge, or current. The
potential difference, or voltage, between two points is the cause ("'pressure"), and the opposi-
tion is the resistance encountered.
An excellent analogy for the simplest of electrical circuits is the water in a hose connected to
a pressure valve. as discussed in Chapter 2. Think of the electrons in the copper wire as the water...
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- Fall '19
- SK Abid