Unable to resist at least trying to provide the basis for some
understanding, Steve proceeds.



Jim, you know who you are...



Thank you. Here's a go at a start.



Apparently, because of the way the big bang occurred, when we put a voltage
across a resistor current flows in a manner that we discovered follows the
equation called Ohm's law. The resistor "resists", determines or limits the
current. Oh yea, resistors have this characteristic we call resistance
measured in "Ohms", just for using in the formulas.



Ohms law: I = V/R

Say... 12 Volts on a 50 ohm resistor results in 0.24 amps flowing.



For the same reason (big bang) this removes power from the circuit, or
"dissipates" it. Poof! Gone from the circuit. Resistors happen to turn this
power into heat. The value being discoverable by the power formula:

P=IxV and the variations P=E^2/R and P=I^2xR



It also turns out that ANYTHING else that removes power from a circuit looks
just like a resistor to the circuit (obeys Ohm's law), and *ONLY* things
that LOOK just like a resistor (behave or conduct current according to Ohm's
law) will so remove power from said ckt. IF you didn't catch this, there
are things that are not really resistors, yet act just like them as far as a
circuit is concerned.



Unfortunately, life is fraught with dangers and we have capacitors (C) and
inductors (L)(or things which behave just like them or combinations of
them). When we get into this realm, the "R" from above, just doesn't do it.
Things get all messed up.

These things also "resist" current flow. (or determine or limit it). We
call this form of resisting "Reactance", use the letter "X" to represent it
and it also is measured in "Ohms", just for using in the formulas. Oh yea,
we also use the little subscript letter to indicate if it is an inductive
(l) or capacitive (c)reactance.



Xc ("X" sub c) = 1/(2 x pi x f x C )

Xl ("X" sub L) = 2 x pi x f x L



When we want to talk about the effect or either an "L" or a "C" we simply
use the term "Reactance" It's like a good substitute for "he/she" (the
"wrong one being "they").



Because of (big bang again) the way the current in these (C & L)
corruptions, of our purely resistive world, work out to be 90 degrees out of
phase with the voltage (we are talking about AC now), we had to find a way
to account for them. I won't trouble you with just why now, but we use what
is called the "Series Representation". It looks like two numbers with a +
or - sign between them and all together we call this new kind of (corrupted)
resistance "Impedance". And use the letter "Z" to represent it. It has
some Resistance and some Reactance in there and it will have numbers on
ohms:

In general: It looks like this:

Z = R + jX



The "R" is the same kind of resistor as above, the "X" is one of the
reactances. The "j" helps the mathematicians do the math - like ohms law -
but with the reactance accounted for. In "math speak" the "R" is the "real"
part and the "X" is the "Imaginary" part of the impedance.



Impedance also resists current flow, but with the reactance in there, you
can't use Ohm's law like you used to.



SO... When I say "Impedance" or use "Z" I am talking about whatever happens
to be there. Since I don't know if it is only resistive, called also
"Purely resistive", or has some reactance in it, called "reactive", (or if I
am just too lazy to figure it out at the time), I use this word or symbol to
cover any situation.



Finally, since only the "resistive part" of a circuit dissipates any power,
we like to remove (somehow) all the reactance (or imaginary part) and
somehow make the real part (the resistive part) what we like best (for a
given situation). Doing this is the infinitely complex subject called
"impedance matching". When we make this happen on an antenna, the remaining
"resistive part" sucks power from the circuit (the transmitter circuit)
Poof! BUT converts it into radiated radio frequency energy (RF) also called
an electromagnetic field or wave.



Fortunately for us in this modern day and age, because if it didn't all the
receivers that we have would be useless and we would wonder why we built
them.



Help any???



73 Steve--
Steve N, K,9;d, c. i My email has no u's.

Hi-Ho Stevo, Outstanding reply to Jimbo and a bunch of us out here that
do not really "know" all that we "undetstand" about electronics! There,
I said it for the bunch! No flames from the huddling masses now!

Butch KF5DE

Steve Nosko wrote:
Unable to resist at least trying to provide the basis for some
understanding, Steve proceeds.



Jim, you know who you are...

snippity-snip

Steve's info will get you a beginners understanding of circuit
theory which is based on a low-frequency, quasi-static simplification
of electromagnetic theory. Unfortunately, anything that has any
appreciable length, such as a transmission line or an antenna, or
a long coil of wire as Yuri and Cecil are arguing about,
can't be adequately explained by simple circuit theory; you have to
study wave mechanics to get any real idea of what is happening
in these situations. That isn't the end of it, though, since in order
to understand what is happening when an object radiates, you
have to understand Maxwell's equations. In order to understand
Maxwell's equations, you'd better know vector calculus. That isn't the
end, either, but it's as close as any *normal* human wants to go.
Whenever someone who was taught circuit theory tries to
apply its vocabulary and concepts to explain all electromagnetic
phenomena, that someone is going to run into trouble and
come up with a multitude of idiocies for which which he'll find no end of
people ready to criticize him.
This is the problem: Cecil and Yuri want to explain the current taper
through a long solenoidal coil using the vocabulary and concepts of
circuit theory rather than the difficult but more precise
language of electromagnetic theory. So far they've failed
miserably, not least because they don't even seem to have
a coherent idea of what they mean by "current flow." I
wish them luck, but I hope no one takes any of their
ideas seriously.
73,
Tom Donaly, KA6RUH






Steve wrote,

Unable to resist at least trying to provide the basis for some
understanding, Steve proceeds.



Jim, you know who you are...



Thank you. Here's a go at a start.



Apparently, because of the way the big bang occurred, when we put a voltage
across a resistor current flows in a manner that we discovered follows the
equation called Ohm's law. The resistor "resists", determines or limits the
current. Oh yea, resistors have this characteristic we call resistance
measured in "Ohms", just for using in the formulas.



Ohms law: I = V/R

Say... 12 Volts on a 50 ohm resistor results in 0.24 amps flowing.



For the same reason (big bang) this removes power from the circuit, or
"dissipates" it. Poof! Gone from the circuit. Resistors happen to turn this
power into heat. The value being discoverable by the power formula:

P=IxV and the variations P=E^2/R and P=I^2xR



It also turns out that ANYTHING else that removes power from a circuit looks
just like a resistor to the circuit (obeys Ohm's law), and *ONLY* things
that LOOK just like a resistor (behave or conduct current according to Ohm's
law) will so remove power from said ckt. IF you didn't catch this, there
are things that are not really resistors, yet act just like them as far as a
circuit is concerned.



Unfortunately, life is fraught with dangers and we have capacitors (C) and
inductors (L)(or things which behave just like them or combinations of
them). When we get into this realm, the "R" from above, just doesn't do it.
Things get all messed up.

These things also "resist" current flow. (or determine or limit it). We
call this form of resisting "Reactance", use the letter "X" to represent it
and it also is measured in "Ohms", just for using in the formulas. Oh yea,
we also use the little subscript letter to indicate if it is an inductive
(l) or capacitive (c)reactance.



Xc ("X" sub c) = 1/(2 x pi x f x C )

Xl ("X" sub L) = 2 x pi x f x L



When we want to talk about the effect or either an "L" or a "C" we simply
use the term "Reactance" It's like a good substitute for "he/she" (the
"wrong one being "they").



Because of (big bang again) the way the current in these (C & L)
corruptions, of our purely resistive world, work out to be 90 degrees out of
phase with the voltage (we are talking about AC now), we had to find a way
to account for them. I won't trouble you with just why now, but we use what
is called the "Series Representation". It looks like two numbers with a +
or - sign between them and all together we call this new kind of (corrupted)
resistance "Impedance". And use the letter "Z" to represent it. It has
some Resistance and some Reactance in there and it will have numbers on
ohms:

In general: It looks like this:

Z = R + jX



The "R" is the same kind of resistor as above, the "X" is one of the
reactances. The "j" helps the mathematicians do the math - like ohms law -
but with the reactance accounted for. In "math speak" the "R" is the "real"
part and the "X" is the "Imaginary" part of the impedance.



Impedance also resists current flow, but with the reactance in there, you
can't use Ohm's law like you used to.



SO... When I say "Impedance" or use "Z" I am talking about whatever happens
to be there. Since I don't know if it is only resistive, called also
"Purely resistive", or has some reactance in it, called "reactive", (or if I
am just too lazy to figure it out at the time), I use this word or symbol to
cover any situation.



Finally, since only the "resistive part" of a circuit dissipates any power,
we like to remove (somehow) all the reactance (or imaginary part) and
somehow make the real part (the resistive part) what we like best (for a
given situation). Doing this is the infinitely complex subject called
"impedance matching". When we make this happen on an antenna, the remaining
"resistive part" sucks power from the circuit (the transmitter circuit)
Poof! BUT converts it into radiated radio frequency energy (RF) also called
an electromagnetic field or wave.



Fortunately for us in this modern day and age, because if it didn't all the
receivers that we have would be useless and we would wonder why we built
them.



Help any???



73 Steve--
Steve N, K,9;d, c. i My email has no u's.

Time out!! You people are taking all this far to seriously. Just throw
an aerial out the window, feed it to your rig via a tuner, and enjoy
Amateur radio.

Butch Magee KF5DE

Tdonaly wrote:
Steve's info will get you a beginners understanding of circuit
theory which is based on a low-frequency, quasi-static simplification
of electromagnetic theory. Unfortunately, anything that has any
appreciable length, such as a transmission line or an antenna, or
a long coil of wire as Yuri and Cecil are arguing about,
can't be adequately explained by simple circuit theory; you have to
study wave mechanics to get any real idea of what is happening
in these situations. That isn't the end of it, though, since in order
to understand what is happening when an object radiates, you
have to understand Maxwell's equations. In order to understand
Maxwell's equations, you'd better know vector calculus. That isn't the
end, either, but it's as close as any *normal* human wants to go.
Whenever someone who was taught circuit theory tries to
apply its vocabulary and concepts to explain all electromagnetic
phenomena, that someone is going to run into trouble and
come up with a multitude of idiocies for which which he'll find no end of
people ready to criticize him.
This is the problem: Cecil and Yuri want to explain the current taper
through a long solenoidal coil using the vocabulary and concepts of
circuit theory rather than the difficult but more precise
language of electromagnetic theory. So far they've failed
miserably, not least because they don't even seem to have
a coherent idea of what they mean by "current flow." I
wish them luck, but I hope no one takes any of their
ideas seriously.
73,
Tom Donaly, KA6RUH






Steve wrote,

Unable to resist at least trying to provide the basis for some
understanding, Steve proceeds.



Jim, you know who you are...



Thank you. Here's a go at a start.



Apparently, because of the way the big bang occurred, when we put a voltage
across a resistor current flows in a manner that we discovered follows the
equation called Ohm's law. The resistor "resists", determines or limits the
current. Oh yea, resistors have this characteristic we call resistance
measured in "Ohms", just for using in the formulas.



Ohms law: I = V/R

Say... 12 Volts on a 50 ohm resistor results in 0.24 amps flowing.



For the same reason (big bang) this removes power from the circuit, or
"dissipates" it. Poof! Gone from the circuit. Resistors happen to turn this
power into heat. The value being discoverable by the power formula:

P=IxV and the variations P=E^2/R and P=I^2xR



It also turns out that ANYTHING else that removes power from a circuit looks
just like a resistor to the circuit (obeys Ohm's law), and *ONLY* things
that LOOK just like a resistor (behave or conduct current according to Ohm's
law) will so remove power from said ckt. IF you didn't catch this, there
are things that are not really resistors, yet act just like them as far as a
circuit is concerned.



Unfortunately, life is fraught with dangers and we have capacitors (C) and
inductors (L)(or things which behave just like them or combinations of
them). When we get into this realm, the "R" from above, just doesn't do it.
Things get all messed up.

These things also "resist" current flow. (or determine or limit it). We
call this form of resisting "Reactance", use the letter "X" to represent it
and it also is measured in "Ohms", just for using in the formulas. Oh yea,
we also use the little subscript letter to indicate if it is an inductive
(l) or capacitive (c)reactance.



Xc ("X" sub c) = 1/(2 x pi x f x C )

Xl ("X" sub L) = 2 x pi x f x L



When we want to talk about the effect or either an "L" or a "C" we simply
use the term "Reactance" It's like a good substitute for "he/she" (the
"wrong one being "they").



Because of (big bang again) the way the current in these (C & L)
corruptions, of our purely resistive world, work out to be 90 degrees out of
phase with the voltage (we are talking about AC now), we had to find a way
to account for them. I won't trouble you with just why now, but we use what
is called the "Series Representation". It looks like two numbers with a +
or - sign between them and all together we call this new kind of (corrupted)
resistance "Impedance". And use the letter "Z" to represent it. It has
some Resistance and some Reactance in there and it will have numbers on
ohms:

In general: It looks like this:

Z = R + jX



The "R" is the same kind of resistor as above, the "X" is one of the
reactances. The "j" helps the mathematicians do the math - like ohms law -
but with the reactance accounted for. In "math speak" the "R" is the "real"
part and the "X" is the "Imaginary" part of the impedance.



Impedance also resists current flow, but with the reactance in there, you
can't use Ohm's law like you used to.



SO... When I say "Impedance" or use "Z" I am talking about whatever happens
to be there. Since I don't know if it is only resistive, called also
"Purely resistive", or has some reactance in it, called "reactive", (or if I
am just too lazy to figure it out at the time), I use this word or symbol to
cover any situation.



Finally, since only the "resistive part" of a circuit dissipates any power,
we like to remove (somehow) all the reactance (or imaginary part) and
somehow make the real part (the resistive part) what we like best (for a
given situation). Doing this is the infinitely complex subject called
"impedance matching". When we make this happen on an antenna, the remaining
"resistive part" sucks power from the circuit (the transmitter circuit)
Poof! BUT converts it into radiated radio frequency energy (RF) also called
an electromagnetic field or wave.



Fortunately for us in this modern day and age, because if it didn't all the
receivers that we have would be useless and we would wonder why we built
them.



Help any???



73 Steve--
Steve N, K,9;d, c. i My email has no u's.

"Butch" wrote in message
...
Time out!! You people are taking all this far to seriously. Just throw
an aerial out the window, feed it to your rig via a tuner, and enjoy
Amateur radio.

Butch Magee KF5DE


It just not that simple, Butch.

I'm sure you have heard that Ham radio is a hobby that has many facets;
construction, public service, contesting, field trips, QRP DX, etc. Some of
our members get their kicks merging theory with rag chewing. I don't think
there's any structure to this sub-category, other than to require at least
one mention of Maxwell in every discussion.


Ed
WB6WSN

Steve Nosko wrote:
"Apparently, because of the way the big bang occurred, when we put a
voltage across a resistor current flows in a manner that we discovered
follows the equation called Ohm`s law."

Big bang? Ohm wasn`t around then. He lived 1787 to 1854. Ohm discovered
that current in an electrical resistance is proportional to voltage.

Resistance is the type of impedance (opposition to electrical current)
in which current is locked in step to the applied voltage.

The item called a resistor is the type of resistance that converts
electrical energy to heat energy.

Not all resistances are resistors. Some resistances don`t convert
electrical energy directly into heat. In these non-dissipative
resistances, current drop is in-phase with the applied volts, or voltage
dropped across the resistance is in-phase with current through the
resistance, but it does not cause energy loss. An example of lossless
resistance is the Zo or surge impedance of a transmission line. Zo is
caused by the distributed inductance and capacitance of the line, but
current in the line is in-phase with the voltage across the line. Zo is
the voltage to current ratio of the waves traveling in either direction
on the transmission line. Zo = volts/amps, yet converts no energy to
heat in the lossless line. Another example of lossless resistance is
"radiation resistance". This is the desired antenna load, so it is
hardly a loss. Loss in the wire, earth, and insulators of the antenna
are resistive loads which produce heat but don`t help the signal.

An ohm is the unit of resistance. It is defined at 0-degrees C, of a
uniform column of mercury 106.300 cm long and weighing 14.451 grams. One
ohm is the resistance which drops one voltt when a current of one amp is
passed through it.

Reactances are also defined by their volts to amps ratios (ohms). The
big difference is that reactance does no work and produces no heat.
Opposition to electrical current comes from delay required to store ard
retrieve energy to and from fields in and around the reactances. Current
lags the applied voltage in an inductance. At time = 0, no current flows
into an inductance, but rises exponentially from the instant of initial
energization. Current leads the applied voltage into a capacitance. At
time = 0, full current flows into a capacitance but voltage across the
capacitance is zero and rises exponentially from the instant of initial
energization.

In an a-c circuit, the current through an inductance lags the voltage by
90-degrees. In a a-c circuit, the current through a capacitance leads
the voltage by 90-degrees. Phase shifts are produced by energy storage
in reactance. There is no phase shift in a resistance. No electrical
energy is stored in a resistor, but its matter does have a thermal
capacity. Once its atoms are agitated by heat their inertia is evident
in the resistance`s temperature. It takes time to cool.

Steve wrote: "Things get all messed up."

As old Carson Robinson sang: "Life gets tedious, Don`t it?" Steve gave
the formulas for capacitive and inductive reactances. They have always
seemed convenient to me. Steve says: "---we call this new kind of
(corrupted) resistance "Impedance"."

No. Impedance is the general name for opposition to electricity.
Resistance is the specialized name for the case in which the impedance
alone causes no delay and stores no electrical energy. All electrical
impedance is defined by its voltage to current ratio, and is the total
opposition (resistance and reactance) a circuit offers to the flow of
electricity. For d-c, reactance doesn`t count. For a-c, total opposition
consists of the vector (phasor) sum of resistance and reactance in a
circuit. Impedance is measured in ohms and its reciprocal is called
admittance. The symbol for impedance is Z. The symbol for admittance is
Y.

Steve also writes:
"Poof! BUT converts it into radio frequency energy (RF) also called an
electromagnetic field or wave."

Yes. A radio wave is r-f energy which has escaped the confines of wires
and doesn`t come back. Whenever wires in open space carry high-frequency
current, some energy gets away as a radiated field, having a strength
that varies inversely with the distance.

Best regards, Richard Harrison, KB5WZI

Richard:

Hmmm....

Impedance... let's give it its' proper due!

It was the self taught "electrician", and ultimately Fellow of the Royal
Society, Oliver Heaviside, FRS
[1850 - 1925] who was born in the London slums to a very poor family and who
had never attended
any school beyond the age of 16 who was the person who coined, defined and
first used the terms
"impedance", "admittance", and "reactance".

Oliver Heaviside also gave us Maxwell's Equations in the form we now know
them. Maxwell
wrote his equations in the form of 22 separate equations using the arcane
method of "quaternions".
Heaviside simplified those 22 equations given by Maxwell down to the four
simple equations with
two auxilliary constituent relations that we now know and love.

James Clerk Maxwell was a Cambridge educated mathematician from an affluent
and educated family.
Oliver Heaviside was a poor kid from the London slums who had to go out to
work at age 16 and
never saw the inside of a college or university!

Heaviside never appeared to receive the citation at the ceremony to which he
was invited when he
was inducted as a Fellow of the Royal Society after he was duly elected to
that lofty title by the
greatest Scientists of the day.

"Impedance"... thank you Oliver!

--
Peter K1PO
Indialantic By-the-Sea, FL


"Richard Harrison" wrote in message
...
Steve Nosko wrote:
"Apparently, because of the way the big bang occurred, when we put a
voltage across a resistor current flows in a manner that we discovered
follows the equation called Ohm`s law."

Big bang? Ohm wasn`t around then. He lived 1787 to 1854. Ohm discovered
that current in an electrical resistance is proportional to voltage.

Resistance is the type of impedance (opposition to electrical current)
in which current is locked in step to the applied voltage.

The item called a resistor is the type of resistance that converts
electrical energy to heat energy.

Not all resistances are resistors. Some resistances don`t convert
electrical energy directly into heat. In these non-dissipative
resistances, current drop is in-phase with the applied volts, or voltage
dropped across the resistance is in-phase with current through the
resistance, but it does not cause energy loss. An example of lossless
resistance is the Zo or surge impedance of a transmission line. Zo is
caused by the distributed inductance and capacitance of the line, but
current in the line is in-phase with the voltage across the line. Zo is
the voltage to current ratio of the waves traveling in either direction
on the transmission line. Zo = volts/amps, yet converts no energy to
heat in the lossless line. Another example of lossless resistance is
"radiation resistance". This is the desired antenna load, so it is
hardly a loss. Loss in the wire, earth, and insulators of the antenna
are resistive loads which produce heat but don`t help the signal.

An ohm is the unit of resistance. It is defined at 0-degrees C, of a
uniform column of mercury 106.300 cm long and weighing 14.451 grams. One
ohm is the resistance which drops one voltt when a current of one amp is
passed through it.

Reactances are also defined by their volts to amps ratios (ohms). The
big difference is that reactance does no work and produces no heat.
Opposition to electrical current comes from delay required to store ard
retrieve energy to and from fields in and around the reactances. Current
lags the applied voltage in an inductance. At time = 0, no current flows
into an inductance, but rises exponentially from the instant of initial
energization. Current leads the applied voltage into a capacitance. At
time = 0, full current flows into a capacitance but voltage across the
capacitance is zero and rises exponentially from the instant of initial
energization.

In an a-c circuit, the current through an inductance lags the voltage by
90-degrees. In a a-c circuit, the current through a capacitance leads
the voltage by 90-degrees. Phase shifts are produced by energy storage
in reactance. There is no phase shift in a resistance. No electrical
energy is stored in a resistor, but its matter does have a thermal
capacity. Once its atoms are agitated by heat their inertia is evident
in the resistance`s temperature. It takes time to cool.

Steve wrote: "Things get all messed up."

As old Carson Robinson sang: "Life gets tedious, Don`t it?" Steve gave
the formulas for capacitive and inductive reactances. They have always
seemed convenient to me. Steve says: "---we call this new kind of
(corrupted) resistance "Impedance"."

No. Impedance is the general name for opposition to electricity.
Resistance is the specialized name for the case in which the impedance
alone causes no delay and stores no electrical energy. All electrical
impedance is defined by its voltage to current ratio, and is the total
opposition (resistance and reactance) a circuit offers to the flow of
electricity. For d-c, reactance doesn`t count. For a-c, total opposition
consists of the vector (phasor) sum of resistance and reactance in a
circuit. Impedance is measured in ohms and its reciprocal is called
admittance. The symbol for impedance is Z. The symbol for admittance is
Y.

Steve also writes:
"Poof! BUT converts it into radio frequency energy (RF) also called an
electromagnetic field or wave."

Yes. A radio wave is r-f energy which has escaped the confines of wires
and doesn`t come back. Whenever wires in open space carry high-frequency
current, some energy gets away as a radiated field, having a strength
that varies inversely with the distance.

Best regards, Richard Harrison, KB5WZI

I have been convinced that "impedance" is the ratio of force to response
in any media. That has worked well for me. Maybe there are readers who can
set me straight if I've been wrong.

Jerry



"Peter O. Brackett" wrote in message
news
Richard:

Hmmm....

Impedance... let's give it its' proper due!

It was the self taught "electrician", and ultimately Fellow of the Royal
Society, Oliver Heaviside, FRS
[1850 - 1925] who was born in the London slums to a very poor family and
who
had never attended
any school beyond the age of 16 who was the person who coined, defined and
first used the terms
"impedance", "admittance", and "reactance".

Oliver Heaviside also gave us Maxwell's Equations in the form we now know
them. Maxwell
wrote his equations in the form of 22 separate equations using the arcane
method of "quaternions".
Heaviside simplified those 22 equations given by Maxwell down to the four
simple equations with
two auxilliary constituent relations that we now know and love.

James Clerk Maxwell was a Cambridge educated mathematician from an
affluent
and educated family.
Oliver Heaviside was a poor kid from the London slums who had to go out to
work at age 16 and
never saw the inside of a college or university!

Heaviside never appeared to receive the citation at the ceremony to which
he
was invited when he
was inducted as a Fellow of the Royal Society after he was duly elected to
that lofty title by the
greatest Scientists of the day.

"Impedance"... thank you Oliver!

--
Peter K1PO
Indialantic By-the-Sea, FL


"Richard Harrison" wrote in message
...
Steve Nosko wrote:
"Apparently, because of the way the big bang occurred, when we put a
voltage across a resistor current flows in a manner that we discovered
follows the equation called Ohm`s law."

Big bang? Ohm wasn`t around then. He lived 1787 to 1854. Ohm discovered
that current in an electrical resistance is proportional to voltage.

Resistance is the type of impedance (opposition to electrical current)
in which current is locked in step to the applied voltage.

The item called a resistor is the type of resistance that converts
electrical energy to heat energy.

Not all resistances are resistors. Some resistances don`t convert
electrical energy directly into heat. In these non-dissipative
resistances, current drop is in-phase with the applied volts, or voltage
dropped across the resistance is in-phase with current through the
resistance, but it does not cause energy loss. An example of lossless
resistance is the Zo or surge impedance of a transmission line. Zo is
caused by the distributed inductance and capacitance of the line, but
current in the line is in-phase with the voltage across the line. Zo is
the voltage to current ratio of the waves traveling in either direction
on the transmission line. Zo = volts/amps, yet converts no energy to
heat in the lossless line. Another example of lossless resistance is
"radiation resistance". This is the desired antenna load, so it is
hardly a loss. Loss in the wire, earth, and insulators of the antenna
are resistive loads which produce heat but don`t help the signal.

An ohm is the unit of resistance. It is defined at 0-degrees C, of a
uniform column of mercury 106.300 cm long and weighing 14.451 grams. One
ohm is the resistance which drops one voltt when a current of one amp is
passed through it.

Reactances are also defined by their volts to amps ratios (ohms). The
big difference is that reactance does no work and produces no heat.
Opposition to electrical current comes from delay required to store ard
retrieve energy to and from fields in and around the reactances. Current
lags the applied voltage in an inductance. At time = 0, no current flows
into an inductance, but rises exponentially from the instant of initial
energization. Current leads the applied voltage into a capacitance. At
time = 0, full current flows into a capacitance but voltage across the
capacitance is zero and rises exponentially from the instant of initial
energization.

In an a-c circuit, the current through an inductance lags the voltage by
90-degrees. In a a-c circuit, the current through a capacitance leads
the voltage by 90-degrees. Phase shifts are produced by energy storage
in reactance. There is no phase shift in a resistance. No electrical
energy is stored in a resistor, but its matter does have a thermal
capacity. Once its atoms are agitated by heat their inertia is evident
in the resistance`s temperature. It takes time to cool.

Steve wrote: "Things get all messed up."

As old Carson Robinson sang: "Life gets tedious, Don`t it?" Steve gave
the formulas for capacitive and inductive reactances. They have always
seemed convenient to me. Steve says: "---we call this new kind of
(corrupted) resistance "Impedance"."

No. Impedance is the general name for opposition to electricity.
Resistance is the specialized name for the case in which the impedance
alone causes no delay and stores no electrical energy. All electrical
impedance is defined by its voltage to current ratio, and is the total
opposition (resistance and reactance) a circuit offers to the flow of
electricity. For d-c, reactance doesn`t count. For a-c, total opposition
consists of the vector (phasor) sum of resistance and reactance in a
circuit. Impedance is measured in ohms and its reciprocal is called
admittance. The symbol for impedance is Z. The symbol for admittance is
Y.

Steve also writes:
"Poof! BUT converts it into radio frequency energy (RF) also called an
electromagnetic field or wave."

Yes. A radio wave is r-f energy which has escaped the confines of wires
and doesn`t come back. Whenever wires in open space carry high-frequency
current, some energy gets away as a radiated field, having a strength
that varies inversely with the distance.

Best regards, Richard Harrison, KB5WZI

Tom,I agree with much of what you say but the problem goes much deeper
than that, and much of the blame rests with academics taught.
Let us look at what is called by some as a 'simple dipole'.
The dipole is very inefficient radiator.
The only claim that you can place on it is that it is has a low
impedance
at resonance...Period. There is no calculation available in any of the
touted books that maximum gain per unit length is design related to a
dipole! The dipole is only a reference that other antennas can be
related to even tho it is a very inefficient radiator per unit length.
Over time academics have made the dipole as something very efficient
about which every advance must be related .
That Tom is very incorrect and it is that which is what prevents the
emergence of new ideas that push the envelope. If one just spouts what
is in present day books then they are just followers that suck up the
dipole aproach which thus prevents them from contributing anything
that pushes out the envelope. Education
can only take you so far and it is dependent on those who have
received an education to push the envelope further. If one doesn't do
this then they are just quoting things that were told to them or they
read in some book and thus are not equiped to pushing the envelope.
Until the simple dipole is shead of its illusionary powers by the
academics who write the books newcomers can only copy, and not
progress. Ofcourse, academics who just memorise can still attack
people, those who do not agree with them, in a personal way in the
hope that a raucous crowd of peasants will echo the academics trash
around the Gillotine.

Regards
Art






(Tdonaly) wrote in message ...
Steve's info will get you a beginners understanding of circuit
theory which is based on a low-frequency, quasi-static simplification
of electromagnetic theory. Unfortunately, anything that has any
appreciable length, such as a transmission line or an antenna, or
a long coil of wire as Yuri and Cecil are arguing about,
can't be adequately explained by simple circuit theory; you have to
study wave mechanics to get any real idea of what is happening
in these situations. That isn't the end of it, though, since in order
to understand what is happening when an object radiates, you
have to understand Maxwell's equations. In order to understand
Maxwell's equations, you'd better know vector calculus. That isn't the
end, either, but it's as close as any *normal* human wants to go.
Whenever someone who was taught circuit theory tries to
apply its vocabulary and concepts to explain all electromagnetic
phenomena, that someone is going to run into trouble and
come up with a multitude of idiocies for which which he'll find no end of
people ready to criticize him.
This is the problem: Cecil and Yuri want to explain the current taper
through a long solenoidal coil using the vocabulary and concepts of
circuit theory rather than the difficult but more precise
language of electromagnetic theory. So far they've failed
miserably, not least because they don't even seem to have
a coherent idea of what they mean by "current flow." I
wish them luck, but I hope no one takes any of their
ideas seriously.
73,
Tom Donaly, KA6RUH






Steve wrote,

Unable to resist at least trying to provide the basis for some
understanding, Steve proceeds.

Snip

"Butch" wrote in message
...
Hi-Ho Stevo, Outstanding reply to Jimbo and a bunch of us out here that
do not really "know" all that we "undetstand" about electronics! There,
I said it for the bunch! No flames from the huddling masses now!
Butch KF5DE

Steve Nosko wrote:
Unable to resist at least trying to provide the basis for some
understanding, Steve proceeds.
Jim, you know who you are...
snippity-snip

Thanks, Butch. That was the intent. Glad it it helps. Please don't huddle
and don't be so snippity ( ; - )
--
Steve N, K,9;d, c. i My email has no u's.