EDAboard.com | EDAboard.de | EDAboard.co.uk | WTWH Media

elektroda.net NewsGroups Forum Index - Electronics - **180 degrees out of phase**

Guest

Thu May 15, 2014 11:43 pm

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfwundzeswtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfvb411eswtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfu31uw7swtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xftohyxpswtmtb_at_red.lan...

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?

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfvb411eswtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfu31uw7swtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xftohyxpswtmtb_at_red.lan...

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.

Guest

Fri May 16, 2014 3:58 am

On Thu, 15 May 2014 18:43:09 +0100, Ian Field <gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfwundzeswtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfvb411eswtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfu31uw7swtmtb_at_red.lan...

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.

Guest

Fri May 16, 2014 8:56 pm

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfw8nxkzswtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfwundzeswtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfvb411eswtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfu31uw7swtmtb_at_red.lan...

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?!

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfwundzeswtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfvb411eswtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfu31uw7swtmtb_at_red.lan...

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.

Guest

Fri May 16, 2014 11:48 pm

On Fri, 16 May 2014 15:56:00 +0100, Ian Field <gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfw8nxkzswtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfwundzeswtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfvb411eswtmtb_at_red.lan...

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.

Guest

Sat May 17, 2014 12:07 am

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfyrqdb6swtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfw8nxkzswtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfwundzeswtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfvb411eswtmtb_at_red.lan...

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?

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfw8nxkzswtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfwundzeswtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfvb411eswtmtb_at_red.lan...

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.

Guest

Sat May 17, 2014 2:21 am

On Fri, 16 May 2014 19:07:37 +0100, Ian Field <gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfyrqdb6swtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfw8nxkzswtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfwundzeswtmtb_at_red.lan...

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.

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."

Guest

Sat May 17, 2014 2:33 am

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfyyt9woswtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfyrqdb6swtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfw8nxkzswtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfwundzeswtmtb_at_red.lan...

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.

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfyrqdb6swtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfw8nxkzswtmtb_at_red.lan...

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

gangprobing.alien_at_ntlworld.com> wrote:

"Uncle Peter" <no_at_spam.com> wrote in message

news:op.xfwundzeswtmtb_at_red.lan...

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.

Guest

Mon May 19, 2014 7:30 am

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

Guest

Mon May 19, 2014 8:53 pm

On Mon, 19 May 2014 06:25:09 +0100, <colonel_hack_at_yahoo.com> 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.

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."

Guest

Tue May 20, 2014 1:19 am

<colonel_hack_at_yahoo.com> wrote in message

news:alpine.BSF.2.00.1405181650420.37808_at_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

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.

Guest

Tue May 20, 2014 4:49 am

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

colonel_hack_at_yahoo.com> wrote in message

news:alpine.BSF.2.00.1405181650420.37808_at_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?

Guest

Tue May 20, 2014 4:57 am

On Mon, 19 May 2014 23:49:14 +0100, Rheilly Phoull <rheilly_at_bigslong.com> wrote:

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

colonel_hack_at_yahoo.com> wrote in message

news:alpine.BSF.2.00.1405181650420.37808_at_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?

colonel_hack_at_yahoo.com> wrote in message

news:alpine.BSF.2.00.1405181650420.37808_at_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.

Guest

Tue May 20, 2014 7:30 am

On Mon, 19 May 2014, Uncle Peter wrote:

What is called ``Negative resistance'' is not quite the same. It is

different than just letting Z<1. 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

elektroda.net NewsGroups Forum Index - Electronics - **180 degrees out of phase**