On Apr 9, 9:48*pm, Cecil Moore wrote:
Keith Dysart wrote:
As long as you agree that the imputed energy in the
reflected wave is not dissipated in the source
resistor;

My ethical standards will not allow me to lie about
technical facts in evidence. You cannot bully me
into doing so.

When the average interference is zero, all of the
average reflected energy is dissipated in the source
resistor. It is true for all examples of Fig. 1-1.
You have not presented even one example where
that is not a true statement.

But all you have demonstrated is that the imputed
average power in the reflected wave is *numerically
equal* to the average increase in the dissipation
of the source resistor. Which is good, as long as
that is all you claim. Which it some times seems
to be, especially when you qualify with "interference
is zero".

Finer grained analysis shows that the imputed
energy (not average) in the reflected wave is not
dissipated in the source resistor. The trouble
is, sometimes you agree with this (when you
invoke that interference is present), but other
times you don't (see your response to the opening
paragraph). It is this flip-flop that makes your
actual position difficult to discern.

...Keith

Keith Dysart wrote:
Finer grained analysis shows that the imputed
energy (not average) in the reflected wave is not
dissipated in the source resistor.

It is the joules in instantaneous power that must
be conserved, not the instantaneous power. There
is no such thing as a conservation of power
principle yet all you have presented are power
calculations. "Where's the beef?"

How many joules are there in 100 watts of
instantaneous power?
--
73, Cecil http://www.w5dxp.com

On Apr 10, 8:01*am, Cecil Moore wrote:
Keith Dysart wrote:
Finer grained analysis shows that the imputed
energy (not average) in the reflected wave is not
dissipated in the source resistor.

It is the joules in instantaneous power that must
be conserved, not the instantaneous power. There
is no such thing as a conservation of power
principle yet all you have presented are power
calculations. "Where's the beef?"

The computation using energy instead of power has
also been done (and published here) and found also
to demonstrate that the reflected is not dissipated
in the source resistor.

How many joules are there in 100 watts of
instantaneous power?

Obviously. It depends on how long you let the
100 W of instantaneous power flow. Integrate and
the answer shall be yours.

...Keith

Keith Dysart wrote:
The computation using energy instead of power has
also been done (and published here) and found also
to demonstrate that the reflected is not dissipated
in the source resistor.

Well, that certainly violates the conservation of
energy principle. We know the reflected energy is
not dissipated in the load resistor, by definition.

The only other device in the entire system capable
of dissipation is the source resistor. Since the reflected
energy is not dissipated in the load resistor and you say
it is not dissipated in the source resistor, it would
necessarily have to magically escape the system or build
up to infinity (but it doesn't). You keep digging your
hole deeper and deeper.

How many joules are there in 100 watts of
instantaneous power?

Obviously. It depends on how long you let the
100 W of instantaneous power flow. Integrate and
the answer shall be yours.

I'm not the one making the assertions. How many joules
of energy exist in *YOUR* instantaneous power calculations?
--
73, Cecil http://www.w5dxp.com

On Fri, 11 Apr 2008 13:25:40 GMT
Cecil Moore wrote:

Keith Dysart wrote:
The computation using energy instead of power has
also been done (and published here) and found also
to demonstrate that the reflected is not dissipated
in the source resistor.

Well, that certainly violates the conservation of
energy principle. We know the reflected energy is
not dissipated in the load resistor, by definition.

The only other device in the entire system capable
of dissipation is the source resistor. Since the reflected
energy is not dissipated in the load resistor and you say
it is not dissipated in the source resistor, it would
necessarily have to magically escape the system or build
up to infinity (but it doesn't). You keep digging your
hole deeper and deeper.


You write "The only other device in the entire system capable
of dissipation is the source resistor." which is a correct statement. Unfortunately, the circuit is intended to illustrate the absence of interference under special circumstances but an instant analysis shows that all the power can not be accounted for. We can only conclude that interference is present. Not good because the circuit was intended to illustrate a case of NO interference.

Our choice of a voltage source is incomplete because we did not assign it a mechanism to provide a reactive voltage, allowing the source to only apply a sinsoidal voltage without specifying the current or current timing. As a result, reflected power will return to the source resulting in an apparent loss of power to the system and resistor Rs. It is not a magical loss of power, only the result of interference acting within the cycle.

The circuit is very useful to investigate interference more carefully because on the AVERAGE, the interference IS zero. Using spreadsheets, we can see how the interference both adds and subtracts from the instantaneous applied voltage, resulting in cycling variations in the power applied to the resistor and other circuit elements. A very instructive exercise.

--
73, Roger, W7WKB

Roger Sparks wrote:
You write "The only other device in the entire system capable
of dissipation is the source resistor." which is a correct statement.

Therefore, all power dissipated in the circuit must be dissipated
in the load resistor and the source resistor because there is
nowhere else for it to go. Since the reflected power is not
dissipated in the load, by definition, it has to be dissipated
in the source resistor but not at the exact time of its arrival.
There is nothing wrong with delaying power dissipation for 90
degrees of the cycle. In Parts 2 and 3 of my articles, I will show
how the source decreases it power output to compensate for destructive
interference and increases it power output to compensate for
constructive interference.

Unfortunately, the circuit is intended to illustrate the absence of

[AVERAGE] interference under special circumstances but an instant analysis shows

that all the power can not be accounted for.

Not surprising since there is no conservation of power principle.

We can only conclude that

[instantaneous] interference is present. Not good because the circuit was intended to

illustrate a case of NO [AVERAGE] interference.

I took the liberty of adding adjectives in brackets[*] to your
above statements. It doesn't matter about the instantaneous values
of power since not only do they not have to be conserved, but they
are also "of limited usefulness", according to Eugene Hecht, since
the actual energy content of instantaneous power is undefined even
when the instantaneous power is defined.

The circuit is very useful to investigate interference more carefully because on the AVERAGE,

the interference IS zero. Using spreadsheets, we can see how the
interference both adds and

subtracts from the instantaneous applied voltage, resulting in cycling
variations in the power

applied to the resistor and other circuit elements. A very instructive
exercise.

Instructive as long as we remember that a conservation of power
principle doesn't exist and therefore, equations based on instantaneous
powers do not have to balance. The joules, not the watts, are what must
balance.
--
73, Cecil http://www.w5dxp.com

Cecil Moore wrote:
Roger Sparks wrote:
You write "The only other device in the entire system capable
of dissipation is the source resistor." which is a correct statement.

Therefore, all power dissipated in the circuit must be dissipated
in the load resistor and the source resistor because there is
nowhere else for it to go. Since the reflected power is not
dissipated in the load, by definition, it has to be dissipated
in the source resistor but not at the exact time of its arrival.
There is nothing wrong with delaying power dissipation for 90
degrees of the cycle. In Parts 2 and 3 of my articles, I will show
how the source decreases it power output to compensate for destructive
interference and increases it power output to compensate for
constructive interference.

Unfortunately, the circuit is intended to illustrate the absence of

[AVERAGE] interference under special circumstances but an instant
analysis shows

that all the power can not be accounted for.

Not surprising since there is no conservation of power principle.

The concept of a wave is energy located at a predicted place after some
time period. That is a concept of conservation of power.

We can only conclude that

[instantaneous] interference is present. Not good because the circuit
was intended to

illustrate a case of NO [AVERAGE] interference.

I took the liberty of adding adjectives in brackets[*] to your
above statements. It doesn't matter about the instantaneous values
of power since not only do they not have to be conserved, but they
are also "of limited usefulness", according to Eugene Hecht, since
the actual energy content of instantaneous power is undefined even
when the instantaneous power is defined.

The circuit is very useful to investigate interference more carefully
because on the AVERAGE,

the interference IS zero. Using spreadsheets, we can see how the
interference both adds and

subtracts from the instantaneous applied voltage, resulting in cycling
variations in the power

applied to the resistor and other circuit elements. A very instructive
exercise.

Instructive as long as we remember that a conservation of power
principle doesn't exist and therefore, equations based on instantaneous
powers do not have to balance. The joules, not the watts, are what must
balance.

Forget the conservation of power at your own peril, because we need to
depend upon the predictability of waves of energy acting over time to
solve these problems. When the instantaneous powers do not balance, we
know that we do not yet have the complete solution or complete circuit.


73, Roger, W7WKB

On Apr 11, 3:30*pm, Cecil Moore wrote:
Roger Sparks wrote:
You write "The only other device in the entire system capable
of dissipation is the source resistor." which is a correct statement.

Therefore, all power dissipated in the circuit must be dissipated
in the load resistor and the source resistor because there is
nowhere else for it to go.

Please do not forget the source. It can absorb energy.

Since the reflected power is not
dissipated in the load, by definition, it has to be dissipated
in the source resistor but not at the exact time of its arrival.
There is nothing wrong with delaying power dissipation for 90
degrees of the cycle.

If you can't identify where the energy is stored for those 90
degrees you do not have a complete story. Or you are violating
conservation of energy and therefore have no story what-so-ever.

In Parts 2 and 3 of my articles, I will show
how the source decreases it power output to compensate for destructive
interference and increases it power output to compensate for
constructive interference.

Unfortunately, the circuit is intended to illustrate the absence of
[AVERAGE] interference under special circumstances but an instant analysis shows
that all the power can not be accounted for. *

Not surprising since there is no conservation of power principle.

Conservation of energy means that energy flows must be conserved.
Therefore, conservation of power.

We can only conclude that
[instantaneous] interference is present. Not good because the circuit was intended to
illustrate a case of NO [AVERAGE] interference.

I took the liberty of adding adjectives in brackets[*] to your
above statements. It doesn't matter about the instantaneous values
of power since not only do they not have to be conserved, but they
are also "of limited usefulness", according to Eugene Hecht, since
the actual energy content of instantaneous power is undefined even
when the instantaneous power is defined.

Are you sure that is why Hecht wrote what he did? He would, in all
likelihood, have an apoplexy if he knew how his words were being used.

The circuit is very useful to investigate interference more carefully because on the AVERAGE,

the interference IS zero. *Using spreadsheets, we can see how the
interference both adds and

subtracts from the instantaneous applied voltage, resulting in cycling
variations in the power

applied to the resistor and other circuit elements. *A very instructive
exercise.

Instructive as long as we remember that a conservation of power
principle doesn't exist and therefore, equations based on instantaneous
powers do not have to balance. The joules, not the watts, are what must
balance.

Since the total energies in your equations do not balance either,
there is still a problem with your hypothesis.

It would be helpful, however, if you could actually demonstrate a
system where the energies balance, but the flows do not. This would
settle the matter once and for all. (You won't find one, since
balanced flows are a consequence of conservation of energy).

...Keith

On Apr 11, 9:25*am, Cecil Moore wrote:
Keith Dysart wrote:
The computation using energy instead of power has
also been done (and published here) and found also
to demonstrate that the reflected is not dissipated
in the source resistor.

Well, that certainly violates the conservation of
energy principle. We know the reflected energy is
not dissipated in the load resistor, by definition.

The only other device in the entire system capable
of dissipation is the source resistor. Since the reflected
energy is not dissipated in the load resistor and you say
it is not dissipated in the source resistor, it would
necessarily have to magically escape the system or build
up to infinity (but it doesn't).

You seem to have forgotten that a voltage source can
absorb energy. This happens when the current flows
into it rather than out.

Recall the equation
Ps(t) = Prs(t) + Pg(t)

When the voltage source voltage is greatr than the
voltage at the terminals of the line (Vg(t)), energy
flows from the source into the resistor and the line.
When the voltage at the line terminals is greater
than the voltage source voltage, energy flows from
the line into the resistor and the voltage source.

At all times
Ps(t) = Prs(t) + Pg(t)
holds true.

Conservation of energy at work. No lost energy.

gartuitous comment snipped

How many joules are there in 100 watts of
instantaneous power?

Obviously. It depends on how long you let the
100 W of instantaneous power flow. Integrate and
the answer shall be yours.

I'm not the one making the assertions. How many joules
of energy exist in *YOUR* instantaneous power calculations?

We have been down that path; the spreadsheet has been
published. The flows of energy described by
Ps(t) = Prs(t) + Pg(t)
always balance.

The integration of these energy flows over any interval
also balance.

Energy is conserved. The world is as it should be.

...Keith