We have recently updated our name to the Power and Energy
Division (PED). What does this mean? Aside from needing to get new business
cards it is not a huge change as my colleagues and I will continue to be
focused on applications relating to power and energy in support of our
portfolio of system power products. It is more of having a renewed and greater
strategic focus on applications relating to power and energy, which I
wholeheartedly welcome. Energy is becoming an increasingly valuable commodity
as the world keeps finding ways to consume it at a faster rate than ways to
produce it. Even if we were able to produce energy in unlimited abundance its production
and consumption leaves an indelible mark on the world. A key part of addressing
this demand is making smarter and more efficient use of the energy we produce.
It’s great to see how technologies are evolving in a number of industries to do
this and that we are taking part in it to help!

This leads me to what I intend to write about today: What
is power and energy?

While power and energy are pretty fundamental concepts
and many do understand what they are, I sometimes encounter folks mistakenly
using one in place of the other. They are indeed closely related but still
distinctly different things.

Let me start with energy. It is probably best to look at it in the
classical mechanical sense for a particle in motion. Its kinetic energy is
described by the equation:

E

_{k}= ½ mv^{2}
Where E

_{k}is the energy of a particle, m is its mass, and v is its velocity. As long as this particle in motion is not acted on, its energy remains unchanged. But what if it is acted on by an external force? That leads us to what is defined as work. Mechanical work is a force acting over a displacement or distance. If this force is in the same direction as the displacement the work is defined as positive. Energy is added to the particle. If the force is opposite to the displacement then the work is negative. The energy of the particle is reduced. Work is expressed as:
W = E

_{k2}– E_{k1}
Where E

_{k1}is the energy of the particle before it is acted on and E_{k2}Is the energy of the particle after it has been acted on by a force. Work is a measureable change in energy of that particle.
This leads to potential energy. In the mechanical world
potential energy can be described as what I will call a recoverable force
applied against a displacement. Most typically it would be a mass or weight
lifted a height against gravity. It can also be a force used to pull a spring
over a distance. For gravity the potential energy is by:

E

_{p}= mgy
Where Ep is the potential energy of the particle, m is
its mass, g is gravity, and y is the height of the particle above a set
reference point. Note that weight is the product of mass and gravity. Work
added or detracted correspondingly is lifting or lowering this particle over
vertical distance, against gravity.

With electrical things work and energy is one and the
same as with mechanical things. It is stated that energy cannot be created or
destroyed, only converted from one form to another. Light energy can be
converted to electrical energy with a solar cell. Electrical energy can be
converted to mechanical energy with an electrical motor, and so on. These
processes are not 100% efficient and a good portion of the original energy also
gets converted to heat energy. A common
measure of energy is joules, which is 1 watt-second. You probably are most
familiar with this when you pay your electrical utility bill, which is based on
the amount of kilowatt-hours of electrical energy you consumed since your
previous billing.

Like mechanical systems, energy can be stored in
electrical systems, in particular in the reactive components; the inductors and
capacitors. Energy in an inductor is given by:

E = ½ LI

^{2}
Where E is the energy in joules, L is the inductance in Henrys,
and I is the current in amps. An inductor stores its energy in its magnetic
field. Similarly energy in a capacitor is given by:

E = ½ CV

^{2}
Where E Is the energy in joules, C is the capacitance in
Farads, and V is the electric potential in volts. A capacitor stores its energy
in its electric field.

Hopefully this gives you a little more appreciation about
what energy (and work) is. Look for my
upcoming second part when I tie it all together with power!

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