Dave said:
Actually, James Watt never performed any electrical experiments, but
there is a Watt's Law that is used in electrics and electronics.
Of course we always have the P=IE equation that is explained in physics
books. There are also plenty of explanations in the physics books on
how it has been equated to James Watt. In this I can quote:
"WORK, POWER, AND ENERGY ... Before we can discuss the next important
part of this lesson, power in d-c circuits, it is important that you
know the difference between work, power, energy.
In a scientific sense, work is the overcoming of the opposition. A man
does work when he lifts a crated television set from the warehouse
platform into a truck or when he drags the crate along the platform. But
the man does no work at all, in the scientific sense of the word, no
matter how hard he pushes or pulls if he does not lift or move the
crate. If the resistance offered by the crate to being moved is not
overcome, no work is done.
Work is measured by the product of a force times the distance through
which the force moves. In a mechanical system, the most common unit of
work is the foot-pound.
In an electrical system, work is measured in watthours or
kilowatt-hours. One kilowatthour of work in an electrical system equals
approximately 2,660,000 ft-lb (foot-pounds) of work.
The work done by a man carrying a 50-lb audio amplifier up a flight of
stairs 12 ft high is 50 lb X 12 ft = 600 ft-lb. From the standpoint of
work done, it makes no difference whether the man does the job in an
hour or in a minute.
But the amount of power required to do the job does depend on time. The
amount of power required to do a job in one minute is 60 times the power
required to do it in one hour. The term "power" includes the idea of
time. Power is the speed, or rate, of doing work. Then,
power = work or work = power X time
----
time
The popular unit for measuring power in mechanical systems is the
horsepower. If a machine can do 33,000 ft-lb of work in one minute, its
power is one horsepower.
The practical units of power in electrical circuits are the watt and
kilowatt. One kilowatt (abbreviated kw) equals 1000 watts. Horse-power
and watts are related as follows:
1 hp = 746 watts
1 kw = 1.34 hp
The work done in an electrical circuit, kilowatthours, equals the power
in kilowatts times the number of hours. For example, if the power
required to operate a motor is 2 kw and the motor operates for 7 hr, the
work done is 2 X 7 = 14 kwhr (kilowatthours).
Energy is the capacity to do work. For example, if a battery is able to
do 1 kwhr of work before it must be recharged, the energy stored by the
battery is 1 kwhr. The difference between work and energy is that work
is what has been done by a device, while energy indicates the amount of
work which a source of energy is able to do.
There are many types of energy. A moving car, for example, has
mechanical energy. A charged battery has chemical energy. A hot stove
has heat energy.
An important concept about energy is that, when work is done, the energy
used to do the work is never used up; it is simply changed from one form
to another.
For example, suppose a charged battery causes current to flow in a
circuit. Chemical energy of the battery has changed to electric energy
in the circuit. Suppose the electric energy of the circuit causes a
vacuum-tube filament to heat up; now the electric energy has changed to
heat energy. When someone talks into a microphone and thus generates an
input signal to an amplifier, the acoustic energy of the sound waves is
changed into electric energy."
From my old physics handout lab sheets back in 1965.
It is
taken from James Watt since what we are measuring in this electrical
application is power. Since it is a measure of power (which Law Watt did
compile), it is directly related to a unit of energy called a Joule and
indirectly related to Horsepower. Neither of those terms are used much
in electrical analysis, but when or if you attend a program on
electronics you will learn how to apply these and cross-check between
any or all of them, or either get a bad grade or flunk out. All of these
units of measurement are standards in electricity and used constantly.
It has no bearing on steam and/or mechanical energy producing devices
that Watt did perform experiments on, other than it is related due to it
being a measure of a form of power, amount of electrons that move past a
noted point at a noted rate of flow for a noted period of time.
You don't have to take my word for any of this, search for Watt's Law
and you will see references that show this is a Law describing
electrical power. If you read long enough you will find all the
information I've posted here, which agrees with your assessment for the
most part, and if you don't read far enough you may come to the
conclusion Watt's Law has nothing to do with electrical and you would be
mistaken.
There is a connection tho that watts
You are indirectly correct in this as heat is a byproduct of power, in
this case electrical, and has to be factored in whenever you move past
the simplistic parts of circuit analysis.
I think that a good read in a physics book
There's some fun in letting the smoke out. :-D
The worst smelling component is the old selenium rectifier. Phew!
