If you built a circuit with a big inductor and a big capacitor in series, such that the resonant frequency was 50Hz, then connected it to the mains, would you get current flowing 180 degrees out of phase with the voltage, and run the meter backwards?

--
Her voice had that tense grating quality, like a first-generation thermal paper fax machine that needed a band tightened.

On 09/05/2014 23:56, Uncle Peter wrote:
If you built a circuit with a big inductor and a big capacitor in
series, such that the resonant frequency was 50Hz, then connected it to
the mains, would you get current flowing 180 degrees out of phase with
the voltage, and run the meter backwards?

No.

You'd just blow a fuse somewhere (or the inductor or capacitor would
blow) since you've just connected something that's a dead short at 50Hz
across 50Hz mains.

--

Brian Gregory (in the UK).
To email me please remove all the letter vee from my email address.

On Sat, 10 May 2014 16:52:02 +0100, Brian Gregory wrote:

On 09/05/2014 23:56, Uncle Peter wrote:
If you built a circuit with a big inductor and a big capacitor in
series, such that the resonant frequency was 50Hz, then connected it to
the mains, would you get current flowing 180 degrees out of phase with
the voltage, and run the meter backwards?

No.

You'd just blow a fuse somewhere (or the inductor or capacitor would
blow) since you've just connected something that's a dead short at 50Hz
across 50Hz mains.

In that case what about the above in series with a load?

--
Q: Why can't you have a circumcised Morris dancer?
A: Because you have to be a complete prick to be a Morris dancer.

"Uncle Peter" wrote in message
news
On Sat, 10 May 2014 16:52:02 +0100, Brian Gregory
wrote:

On 09/05/2014 23:56, Uncle Peter wrote:
If you built a circuit with a big inductor and a big capacitor in
series, such that the resonant frequency was 50Hz, then connected it to
the mains, would you get current flowing 180 degrees out of phase with
the voltage, and run the meter backwards?

No.

You'd just blow a fuse somewhere (or the inductor or capacitor would
blow) since you've just connected something that's a dead short at 50Hz
across 50Hz mains.

In that case what about the above in series with a load?

You need a really huge permanent magnet clamped on the electricity meter so
the V & I coils saturate their cores on alternate half-cycles.

On Sat, 10 May 2014 22:09:58 +0100, Ian Field wrote:



"Uncle Peter" wrote in message
news
On Sat, 10 May 2014 16:52:02 +0100, Brian Gregory
wrote:

On 09/05/2014 23:56, Uncle Peter wrote:
If you built a circuit with a big inductor and a big capacitor in
series, such that the resonant frequency was 50Hz, then connected it to
the mains, would you get current flowing 180 degrees out of phase with
the voltage, and run the meter backwards?

No.

You'd just blow a fuse somewhere (or the inductor or capacitor would
blow) since you've just connected something that's a dead short at 50Hz
across 50Hz mains.

In that case what about the above in series with a load?

You need a really huge permanent magnet clamped on the electricity meter so
the V & I coils saturate their cores on alternate half-cycles.

It's a digital meter :-/

--
What do you call kinky sex with chocolate?
S&M&M

On 10/05/2014 16:52, Brian Gregory wrote:
On 09/05/2014 23:56, Uncle Peter wrote:
If you built a circuit with a big inductor and a big capacitor in
series, such that the resonant frequency was 50Hz, then connected it to
the mains, would you get current flowing 180 degrees out of phase with
the voltage, and run the meter backwards?

No.

You'd just blow a fuse somewhere (or the inductor or capacitor would
blow) since you've just connected something that's a dead short at 50Hz
across 50Hz mains.


And, come to think of it, you'd also get some ludicrously high voltage
at the junction of the inductor and capacitor, potentially instantly
destroying the capacitor. Exactly how high depends on how perfect the
inductor and capacitor are and how exactly they resonate at the mains
frequency.

--

Brian Gregory (in the UK).
To email me please remove all the letter vee from my email address.

"Uncle Peter" schreef in bericht news
If you built a circuit with a big inductor and a big capacitor in series,
such that the resonant frequency was 50Hz, then connected it to the mains,
would you get current flowing 180 degrees out of phase with the voltage, and
run the meter backwards?

--
Her voice had that tense grating quality, like a first-generation thermal
paper fax machine that needed a band tightened.


No, but you may experience some expensive fireworks. Worst (or best?) case
you may earn a Darwin award.

petrus bitbyter

"petrus bitbyter" wrote in message
l.nl...


"Uncle Peter" schreef in bericht news
If you built a circuit with a big inductor and a big capacitor in series,
such that the resonant frequency was 50Hz, then connected it to the mains,
would you get current flowing 180 degrees out of phase with the voltage,
and run the meter backwards?

Dont! - he's stupid enough to do it.

On Mon, 12 May 2014 18:27:52 +0100, Ian Field wrote:



"petrus bitbyter" wrote in message
l.nl...


"Uncle Peter" schreef in bericht news
If you built a circuit with a big inductor and a big capacitor in series,
such that the resonant frequency was 50Hz, then connected it to the mains,
would you get current flowing 180 degrees out of phase with the voltage,
and run the meter backwards?

Dont! - he's stupid enough to do it.

What are you telling him not to do? His text is missing.

--
I would defend the liberty of consenting adult creationists to practice whatever intellectual perversions they like in the privacy of their own homes; but it is also necessary to protect the young and innocent. -- Arthur C. Clarke

"Uncle Peter" wrote in message
news
On Mon, 12 May 2014 18:27:52 +0100, Ian Field
wrote:



"petrus bitbyter" wrote in message
l.nl...


"Uncle Peter" schreef in bericht news
If you built a circuit with a big inductor and a big capacitor in
series,
such that the resonant frequency was 50Hz, then connected it to the
mains,
would you get current flowing 180 degrees out of phase with the voltage,
and run the meter backwards?

Dont! - he's stupid enough to do it.

What are you telling him not to do? His text is missing.

He was telling you to put a series resonant LC across the mains.

On Wed, 14 May 2014 18:22:04 +0100, Ian Field wrote:



"Uncle Peter" wrote in message
news
On Mon, 12 May 2014 18:27:52 +0100, Ian Field
wrote:



"petrus bitbyter" wrote in message
l.nl...


"Uncle Peter" schreef in bericht news
If you built a circuit with a big inductor and a big capacitor in
series,
such that the resonant frequency was 50Hz, then connected it to the
mains,
would you get current flowing 180 degrees out of phase with the voltage,
and run the meter backwards?

Dont! - he's stupid enough to do it.

What are you telling him not to do? His text is missing.

He was telling you to put a series resonant LC across the mains.

That was my idea.

--
I'm not so think as you drunk I am...

"Uncle Peter" wrote in message
news
On Wed, 14 May 2014 18:22:04 +0100, Ian Field
wrote:



"Uncle Peter" wrote in message
news
On Mon, 12 May 2014 18:27:52 +0100, Ian Field
wrote:



"petrus bitbyter" wrote in message
l.nl...


"Uncle Peter" schreef in bericht news
If you built a circuit with a big inductor and a big capacitor in
series,
such that the resonant frequency was 50Hz, then connected it to the
mains,
would you get current flowing 180 degrees out of phase with the
voltage,
and run the meter backwards?

Dont! - he's stupid enough to do it.

What are you telling him not to do? His text is missing.

He was telling you to put a series resonant LC across the mains.

That was my idea.

And I told him you were stupid enough to do it.

On Wed, 14 May 2014 22:04:54 +0100, Ian Field wrote:



"Uncle Peter" wrote in message
news
On Wed, 14 May 2014 18:22:04 +0100, Ian Field
wrote:



"Uncle Peter" wrote in message
news On Mon, 12 May 2014 18:27:52 +0100, Ian Field
wrote:



"petrus bitbyter" wrote in message
l.nl...


Dont! - he's stupid enough to do it.

What are you telling him not to do? His text is missing.

He was telling you to put a series resonant LC across the mains.

That was my idea.

And I told him you were stupid enough to do it.

Then what was the DON'T!?

--
A guy says, "I remember the first time I used alcohol as a substitute for women."
"Yeah what happened?" asked the other.
The first guy replies, "Well, I got my penis stuck in the neck of the bottle."

"Uncle Peter" wrote in message
news
On Wed, 14 May 2014 22:04:54 +0100, Ian Field
wrote:



"Uncle Peter" wrote in message
news
On Wed, 14 May 2014 18:22:04 +0100, Ian Field
wrote:



"Uncle Peter" wrote in message
news On Mon, 12 May 2014 18:27:52 +0100, Ian Field
wrote:



"petrus bitbyter" wrote in message
l.nl...


Dont! - he's stupid enough to do it.

What are you telling him not to do? His text is missing.

He was telling you to put a series resonant LC across the mains.

That was my idea.

And I told him you were stupid enough to do it.

Then what was the DON'T!?

Assuming all theoretical ideal components, your series resonant circuit
would draw infinite current and produce infinite voltage at the junction
between L & C - you'd vaporise the whole galaxy.

On Thu, 15 May 2014 17:17:55 +0100, Ian Field wrote:



"Uncle Peter" wrote in message
news
On Wed, 14 May 2014 22:04:54 +0100, Ian Field
wrote:



"Uncle Peter" wrote in message
news On Wed, 14 May 2014 18:22:04 +0100, Ian Field
wrote:



"Uncle Peter" wrote in message
news




He was telling you to put a series resonant LC across the mains.

That was my idea.

And I told him you were stupid enough to do it.

Then what was the DON'T!?

Assuming all theoretical ideal components, your series resonant circuit
would draw infinite current and produce infinite voltage at the junction
between L & C - you'd vaporise the whole galaxy.

So what about putting in in series with a 240V load?

--
Exersize: the act of removing excess baggage

"Uncle Peter" wrote in message
news
On Thu, 15 May 2014 17:17:55 +0100, Ian Field
wrote:



"Uncle Peter" wrote in message
news
On Wed, 14 May 2014 22:04:54 +0100, Ian Field
wrote:



"Uncle Peter" wrote in message
news On Wed, 14 May 2014 18:22:04 +0100, Ian Field
wrote:



"Uncle Peter" wrote in message
news




He was telling you to put a series resonant LC across the mains.

That was my idea.

And I told him you were stupid enough to do it.

Then what was the DON'T!?

Assuming all theoretical ideal components, your series resonant circuit
would draw infinite current and produce infinite voltage at the junction
between L & C - you'd vaporise the whole galaxy.

So what about putting in in series with a 240V load?

It would see the load as a loss vector which would change the whole dynamic.

On Thu, 15 May 2014 18:43:09 +0100, Ian Field wrote:



"Uncle Peter" wrote in message
news
On Thu, 15 May 2014 17:17:55 +0100, Ian Field
wrote:



"Uncle Peter" wrote in message
news On Wed, 14 May 2014 22:04:54 +0100, Ian Field
wrote:



"Uncle Peter" wrote in message
news






And I told him you were stupid enough to do it.

Then what was the DON'T!?

Assuming all theoretical ideal components, your series resonant circuit
would draw infinite current and produce infinite voltage at the junction
between L & C - you'd vaporise the whole galaxy.

So what about putting in in series with a 240V load?

It would see the load as a loss vector which would change the whole dynamic.

Explain further. The added circuit should be a "negative resistance", which when added to a normal resistance would app to.... zero?!

--
Interesting fact number 476:
80% of millionaires drive used cars.

"Uncle Peter" wrote in message
news
On Thu, 15 May 2014 18:43:09 +0100, Ian Field
wrote:



"Uncle Peter" wrote in message
news
On Thu, 15 May 2014 17:17:55 +0100, Ian Field
wrote:



"Uncle Peter" wrote in message
news On Wed, 14 May 2014 22:04:54 +0100, Ian Field
wrote:



"Uncle Peter" wrote in message
news






And I told him you were stupid enough to do it.

Then what was the DON'T!?

Assuming all theoretical ideal components, your series resonant circuit
would draw infinite current and produce infinite voltage at the
junction
between L & C - you'd vaporise the whole galaxy.

So what about putting in in series with a 240V load?

It would see the load as a loss vector which would change the whole
dynamic.

Explain further. The added circuit should be a "negative resistance",
which when added to a normal resistance would app to.... zero?!

In theoretically ideal components, C has current leading voltage by 90 deg
and L has current lagging by 90.

In real world components, losses alter the vector angles with the end result
that your series resonant circuit doesn't draw infinite current and produce
infinite voltage.

On Fri, 16 May 2014 15:56:00 +0100, Ian Field wrote:



"Uncle Peter" wrote in message
news
On Thu, 15 May 2014 18:43:09 +0100, Ian Field
wrote:



"Uncle Peter" wrote in message
news On Thu, 15 May 2014 17:17:55 +0100, Ian Field
wrote:



"Uncle Peter" wrote in message
news








Assuming all theoretical ideal components, your series resonant circuit
would draw infinite current and produce infinite voltage at the
junction
between L & C - you'd vaporise the whole galaxy.

So what about putting in in series with a 240V load?

It would see the load as a loss vector which would change the whole
dynamic.

Explain further. The added circuit should be a "negative resistance",
which when added to a normal resistance would app to.... zero?!

In theoretically ideal components, C has current leading voltage by 90 deg
and L has current lagging by 90.

In real world components, losses alter the vector angles with the end result
that your series resonant circuit doesn't draw infinite current and produce
infinite voltage.

But I wonder if it would help reduce the meter reading?

--
Light travels faster than sound. This is why some people
appear bright until you hear them speak.

"Uncle Peter" wrote in message
news
On Fri, 16 May 2014 15:56:00 +0100, Ian Field
wrote:



"Uncle Peter" wrote in message
news
On Thu, 15 May 2014 18:43:09 +0100, Ian Field
wrote:



"Uncle Peter" wrote in message
news On Thu, 15 May 2014 17:17:55 +0100, Ian Field
wrote:



"Uncle Peter" wrote in message
news








Assuming all theoretical ideal components, your series resonant
circuit
would draw infinite current and produce infinite voltage at the
junction
between L & C - you'd vaporise the whole galaxy.

So what about putting in in series with a 240V load?

It would see the load as a loss vector which would change the whole
dynamic.

Explain further. The added circuit should be a "negative resistance",
which when added to a normal resistance would app to.... zero?!

In theoretically ideal components, C has current leading voltage by 90
deg
and L has current lagging by 90.

In real world components, losses alter the vector angles with the end
result
that your series resonant circuit doesn't draw infinite current and
produce
infinite voltage.

But I wonder if it would help reduce the meter reading?

It incinerates your meter so there isn't much left to read.

You could buy all 110V appliances and use capacitor "wattless droppers".

That would put I out of phase with V and screw up the meter readings.

Each capacitor needs to be dimensioned for its load - Late hybrid TCE CTVs
used a wattless dropper for the 300mA heater chain, the capacitor was
4.3uF - you can scale that for the current draw of your appliances.

On Fri, 16 May 2014 19:07:37 +0100, Ian Field wrote:



"Uncle Peter" wrote in message
news
On Fri, 16 May 2014 15:56:00 +0100, Ian Field
wrote:



"Uncle Peter" wrote in message
news On Thu, 15 May 2014 18:43:09 +0100, Ian Field
wrote:



"Uncle Peter" wrote in message
news










It would see the load as a loss vector which would change the whole
dynamic.

Explain further. The added circuit should be a "negative resistance",
which when added to a normal resistance would app to.... zero?!

In theoretically ideal components, C has current leading voltage by 90
deg
and L has current lagging by 90.

In real world components, losses alter the vector angles with the end
result
that your series resonant circuit doesn't draw infinite current and
produce
infinite voltage.

But I wonder if it would help reduce the meter reading?

It incinerates your meter so there isn't much left to read.

You could buy all 110V appliances and use capacitor "wattless droppers".

That would put I out of phase with V and screw up the meter readings.

Meters (especially electronic ones) don't mind up to 90 degrees out of phase. I was looking for 180 degrees out of phase.

Each capacitor needs to be dimensioned for its load - Late hybrid TCE CTVs
used a wattless dropper for the 300mA heater chain, the capacitor was
4.3uF - you can scale that for the current draw of your appliances.

So an extension to the house then.

--
A note left for a pianist from his wife: "Gone Chopin, have Liszt, Bach in a Minuet."

"Uncle Peter" wrote in message
news
On Fri, 16 May 2014 19:07:37 +0100, Ian Field
wrote:



"Uncle Peter" wrote in message
news
On Fri, 16 May 2014 15:56:00 +0100, Ian Field
wrote:



"Uncle Peter" wrote in message
news On Thu, 15 May 2014 18:43:09 +0100, Ian Field
wrote:



"Uncle Peter" wrote in message
news










It would see the load as a loss vector which would change the whole
dynamic.

Explain further. The added circuit should be a "negative resistance",
which when added to a normal resistance would app to.... zero?!

In theoretically ideal components, C has current leading voltage by 90
deg
and L has current lagging by 90.

In real world components, losses alter the vector angles with the end
result
that your series resonant circuit doesn't draw infinite current and
produce
infinite voltage.

But I wonder if it would help reduce the meter reading?

It incinerates your meter so there isn't much left to read.

You could buy all 110V appliances and use capacitor "wattless droppers".

That would put I out of phase with V and screw up the meter readings.

Meters (especially electronic ones) don't mind up to 90 degrees out of
phase. I was looking for 180 degrees out of phase.

Each capacitor needs to be dimensioned for its load - Late hybrid TCE
CTVs
used a wattless dropper for the 300mA heater chain, the capacitor was
4.3uF - you can scale that for the current draw of your appliances.

So an extension to the house then.

Each cap has to be dimensioned for its load - you can't bulk-dropper the
whole house.

Its basically approximating to a constant current supply, filament bulbs can
have accelerated end of life reactive loads like transformers can be pretty
unpredictable.

I have what used to be an IR/UV therapy lamp (till I broke the UV tube). The
2 IR bars add up to 110V and act as ballast for the tube when both on
together, the mans ir half wave rectified for IR only. As the IR bit is 110V
I could run it off a wattless dropper if I had a capacitor big enough.

On Fri, 16 May 2014, Uncle Peter wrote:

But I wonder if it would help reduce the meter reading?

No. The coil and the capacitor add up (ideally) to zero impedence, so it's
like you put a wire accoss the mains. It burns and/or the breaker/fuse
opens. For real components the coil & cap still cancel out and leave
basically the resistance of the coil, which for a ``large'' coil is
probably small, so again bad things happen.

But you have a basic fallacy anyway. At resonance the current is /in/
phase with the voltage, the capacitive and inductive reactance cancel out
so the circuit looks purely resistive.

If you like complex impedences (and adding a bit of series R &
using the EE jxj=-1 & w standing in for omega = 2 pi f)

XL=jwL
XC=1/jwC
Z=jwL+1/jwC+R

at resonance w=sqrt(1/LC)
Z=j( sqrt(1/LC)L-1/sqrt(1/LC)C )+R=j( sqrt(L/C)-sqrt(L/C) )+R=R
I=V/R

and

VL=(V/R)jwL = j(V/R)sqrt(L/C)
VC=(V/R)(1/jwC)=-j(V/R)sqrt(L/C)

The voltages on the cap & coil are 90 out of phase with the currrent and
180 out with each other so they add to zero but can be very large
depending on the choice of R, L & C (and clearly they as well as the
current get large as R gets small).

If you did have current 180 out of phase with voltage you would have to be
supplying power and the meter ``should'' run backwards (it may or may not,
depending on design) but the power company doesn't normally buy power at
the rate they sell it so they wouldn't like it.

Ron

aye means yes to a sailor
eye in a needle I can thread
i is the imaginary unit
but EEs use j instead

On Mon, 19 May 2014 06:25:09 +0100, wrote:

On Fri, 16 May 2014, Uncle Peter wrote:

But I wonder if it would help reduce the meter reading?

No. The coil and the capacitor add up (ideally) to zero impedence, so it's
like you put a wire accoss the mains. It burns and/or the breaker/fuse
opens. For real components the coil & cap still cancel out and leave
basically the resistance of the coil, which for a ``large'' coil is
probably small, so again bad things happen.

But you have a basic fallacy anyway. At resonance the current is /in/
phase with the voltage, the capacitive and inductive reactance cancel out
so the circuit looks purely resistive.

If you like complex impedences (and adding a bit of series R &
using the EE jxj=-1 & w standing in for omega = 2 pi f)

XL=jwL
XC=1/jwC
Z=jwL+1/jwC+R

at resonance w=sqrt(1/LC)
Z=j( sqrt(1/LC)L-1/sqrt(1/LC)C )+R=j( sqrt(L/C)-sqrt(L/C) )+R=R
I=V/R

and

VL=(V/R)jwL = j(V/R)sqrt(L/C)
VC=(V/R)(1/jwC)=-j(V/R)sqrt(L/C)

The voltages on the cap & coil are 90 out of phase with the currrent and
180 out with each other so they add to zero but can be very large
depending on the choice of R, L & C (and clearly they as well as the
current get large as R gets small).

If you did have current 180 out of phase with voltage you would have to be
supplying power and the meter ``should'' run backwards (it may or may not,
depending on design) but the power company doesn't normally buy power at
the rate they sell it so they wouldn't like it.

I see. I was reading this and thought "hmmmm....": http://en.wikipedia.org/wiki/Negative_resistance

--
Little Tony was staying with his grandmother for a few days.. He'd been playing outside with the other kids for a while when he came into the house and asked her, "Grandma, what's that called when 2 people sleep in the same room and one is on top of the other?"

She was a little taken, but she decided to just tell him the truth. "It's called sexual intercourse, darling".

Little Tony just said, "Oh, OK," and went back outside to play with the other kids.

A few minutes later he came back in and said angrily, "Grandma, it isn't called sexual intercourse. It's called "Bunk Beds". And Jimmy's mom wants to talk to you."

wrote in message
news:alpine.BSF.2.00.1405181650420.37808@bunrab...
On Fri, 16 May 2014, Uncle Peter wrote:

But I wonder if it would help reduce the meter reading?

No. The coil and the capacitor add up (ideally) to zero impedence, so it's
like you put a wire accoss the mains. It burns and/or the breaker/fuse
opens. For real components the coil & cap still cancel out and leave
basically the resistance of the coil, which for a ``large'' coil is
probably small, so again bad things happen.

But you have a basic fallacy anyway. At resonance the current is /in/
phase with the voltage, the capacitive and inductive reactance cancel out
so the circuit looks purely resistive.

If you like complex impedences (and adding a bit of series R &
using the EE jxj=-1 & w standing in for omega = 2 pi f)

XL=jwL
XC=1/jwC
Z=jwL+1/jwC+R

at resonance w=sqrt(1/LC)
Z=j( sqrt(1/LC)L-1/sqrt(1/LC)C )+R=j( sqrt(L/C)-sqrt(L/C) )+R=R
I=V/R

Peter did all that fancy math at uni, he can do the phase reversal in his
head - by attaching a pair of electrodes either side and passing the whole
meter current through it.

On 20/05/14 03:19, Ian Field wrote:


wrote in message
news:alpine.BSF.2.00.1405181650420.37808@bunrab...
On Fri, 16 May 2014, Uncle Peter wrote:

But I wonder if it would help reduce the meter reading?

No. The coil and the capacitor add up (ideally) to zero impedence, so
it's like you put a wire accoss the mains. It burns and/or the
breaker/fuse opens. For real components the coil & cap still cancel
out and leave basically the resistance of the coil, which for a
``large'' coil is probably small, so again bad things happen.

But you have a basic fallacy anyway. At resonance the current is /in/
phase with the voltage, the capacitive and inductive reactance cancel
out so the circuit looks purely resistive.

If you like complex impedences (and adding a bit of series R &
using the EE jxj=-1 & w standing in for omega = 2 pi f)

XL=jwL
XC=1/jwC
Z=jwL+1/jwC+R

at resonance w=sqrt(1/LC)
Z=j( sqrt(1/LC)L-1/sqrt(1/LC)C )+R=j( sqrt(L/C)-sqrt(L/C) )+R=R
I=V/R

Peter did all that fancy math at uni, he can do the phase reversal in
his head - by attaching a pair of electrodes either side and passing the
whole meter current through it.


Hopefully he will?

On Mon, 19 May 2014 23:49:14 +0100, Rheilly Phoull wrote:

On 20/05/14 03:19, Ian Field wrote:


wrote in message
news:alpine.BSF.2.00.1405181650420.37808@bunrab...
On Fri, 16 May 2014, Uncle Peter wrote:

But I wonder if it would help reduce the meter reading?

No. The coil and the capacitor add up (ideally) to zero impedence, so
it's like you put a wire accoss the mains. It burns and/or the
breaker/fuse opens. For real components the coil & cap still cancel
out and leave basically the resistance of the coil, which for a
``large'' coil is probably small, so again bad things happen.

But you have a basic fallacy anyway. At resonance the current is /in/
phase with the voltage, the capacitive and inductive reactance cancel
out so the circuit looks purely resistive.

If you like complex impedences (and adding a bit of series R &
using the EE jxj=-1 & w standing in for omega = 2 pi f)

XL=jwL
XC=1/jwC
Z=jwL+1/jwC+R

at resonance w=sqrt(1/LC)
Z=j( sqrt(1/LC)L-1/sqrt(1/LC)C )+R=j( sqrt(L/C)-sqrt(L/C) )+R=R
I=V/R

Peter did all that fancy math at uni, he can do the phase reversal in
his head - by attaching a pair of electrodes either side and passing the
whole meter current through it.


Hopefully he will?

Do they do that for fun at parties in Wales?

--
It hurt the way your tongue hurts after you accidentally staple it to the wall.

On Mon, 19 May 2014, Uncle Peter wrote:

I see. I was reading this and thought "hmmmm....":
http://en.wikipedia.org/wiki/Negative_resistance


What is called ``Negative resistance'' is not quite the same. It is
different than just letting Z1. Negative resistance normally refers to a
device where increasing current decreases the voltage, but the sign of the
voltage and current remain the same. i.e. 1mA through the device produces
1V across the device, but 1.1mA produces .9V. Basically, they are equating
R=dV/dI in a non-linear case while I was refering to letting R go complex
but staying linear.

A battery or a generator has current opposite the voltage but an increase
in the magnitude of current also produces a decrease in magnitude
of the voltage. i.e. -100mA @ 3V goes to -150mA @ 2.8V

A resistance which is negative in the strict sense of Ohm's law should
give a current in the opposite direction as the applied voltage that is
proportional to the voltage. The article does show how to make such a
device with an op amp which provide the power. Since capacitors can be
made that are closer to idea than inductors, this idea is used to make a
capacitor look like a close to ideal inductor.

Ron