John S wrote:
On 7/20/2015 11:57 AM, wrote:
John S wrote:
On 7/11/2015 4:52 PM, wrote:
rickman wrote:
On 7/11/2015 3:11 PM, wrote:

OK, but a defined load of 50 Ohms does not give a lot of room to
get the source impedance significantly lower.

For the curious:

https://en.wikipedia.org/wiki/Maximu...ansfer_theorem

And in particular, the section "Maximizing power transfer versus power
efficiency".

I never saw anyone in the other discussion prove that a generator,
conjugate matched to the antenna would reflect back to the antenna 100%
of the signal reflected from the antenna. The example given was a
purely resistive conjugate match oddly enough.

Perhaps the various issues in this example can be dealt with separately?
I would first like to clarify that if the load (or matching network)
impedance has a zero imaginary term it is a purely resistive load.

The above reference deals with complex loads and sources.

Certainly. Real numbers are a subset of complex numbers.

It does not address connecting them with a transmission line as that
is an entirely different subject.

Then let's not discuss it.

However, the two problems are fairly trivially solvable independantly.

The application of conjugate matching is mistaken and misused by most
people.

So what?

There are people that believe Elvis is alive.

Neither have anything to do with how the world actually works.

Suppose you have a laboratory power supply. It will deliver an
adjustable fixed voltage until its current limit is reached. What is the
output impedance of the supply in the region during voltage regulation?
What is the output impedance in current limit?

How long is a rope?

You have nothing to discuss unless you have numbers.

Your question as stated has an infinate number of answers.

As I recall, you said that conjugate matching even works at DC.

Then you recall incorrectly as such a statement is ignorant.

The term is actually "complex conjugate matching" and there are no
complex numbers at DC.

Sure there is. As I said above, "Real numbers are a subset of complex
numbers." What this means is that all the real number we use are
actually complex with an imaginary part of zero. If I have a source of
12+j0, it completely defines the source and you know that you can rely
on it to be 12 regardless of frequency.

Try telling that to a math teacher.

If you have a 12V battery with an internal impedance of 6+j0 ohms, what
is the maximum available output power from the battery into the load?
What is the load impedance when that point is reached?

The question is irrelevant to complex conjugate matching, but since
you need a refresher:

https://en.wikipedia.org/wiki/Maximu...ansfer_theorem

By definition a purely resistive impedance is an impedance who's complex
part equals zero.

Yes. However, I would have put it this way "By definition a pure
resistance is an impedance who's complex part equals zero."

You could, but that is circular.

In what way?

Because you have used resistance to define resistance.

You will not find the phrase "a pure resistance" in technical writting,
the phrase you will find is "purely resistive impedance".

In technical matters, precise language is important, especially when
you are just using language without mathematics.


--
Jim Pennino