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elektroda.net NewsGroups Forum Index - Electronic for beginners - **mutual capacitance?**

Guest

Tue Feb 12, 2019 12:45 am

Looking at network theory and the duality theorems,

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

--

Rich

Guest

Tue Feb 12, 2019 3:45 am

On 2019-02-11, RichD <r_delaney2001_at_yahoo.com> wrote:

Looking at network theory and the duality theorems,

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

you'll see something like mutual capacitance in piezo-electric transformers.

--

When I tried casting out nines I made a hash of it.

Guest

Tue Feb 12, 2019 4:45 pm

On 2/11/19 5:58 PM, RichD wrote:

Looking at network theory and the duality theorems,

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

--

Rich

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

--

Rich

There is. It's usually just called 'capacitance', unless you need to

distinguish it from self-capacitance.

A 1-cm radius isolated sphere has a self-capacitance of 1 cm (Gaussian

units), which is about 1.12 pF.

Cheers

Phil Hobbs

--

Dr Philip C D Hobbs

Principal Consultant

ElectroOptical Innovations LLC / Hobbs ElectroOptics

Optics, Electro-optics, Photonics, Analog Electronics

Briarcliff Manor NY 10510

http://electrooptical.net

http://hobbs-eo.com

Guest

Tue Feb 12, 2019 6:45 pm

On Tue, 12 Feb 2019 10:33:31 -0500, Phil Hobbs

<pcdhSpamMeSenseless_at_electrooptical.net> wrote:

On 2/11/19 5:58 PM, RichD wrote:

Looking at network theory and the duality theorems,

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

--

Rich

There is. It's usually just called 'capacitance', unless you need to

distinguish it from self-capacitance.

A 1-cm radius isolated sphere has a self-capacitance of 1 cm (Gaussian

units), which is about 1.12 pF.

Cheers

Phil Hobbs

Looking at network theory and the duality theorems,

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

--

Rich

There is. It's usually just called 'capacitance', unless you need to

distinguish it from self-capacitance.

A 1-cm radius isolated sphere has a self-capacitance of 1 cm (Gaussian

units), which is about 1.12 pF.

Cheers

Phil Hobbs

There are two commonly given values for the capacitance between the

earth and the moon, 160uF and 3 uF. I think one is 2-wire capacitance

and the smaller one is 3-wire.

Where is the universe's ground lug?

--

John Larkin Highland Technology, Inc

lunatic fringe electronics

Guest

Tue Feb 12, 2019 6:45 pm

On 2/12/19 11:47 AM, John Larkin wrote:

On Tue, 12 Feb 2019 10:33:31 -0500, Phil Hobbs

pcdhSpamMeSenseless_at_electrooptical.net> wrote:

On 2/11/19 5:58 PM, RichD wrote:

Looking at network theory and the duality theorems,

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

--

Rich

There is. It's usually just called 'capacitance', unless you need to

distinguish it from self-capacitance.

A 1-cm radius isolated sphere has a self-capacitance of 1 cm (Gaussian

units), which is about 1.12 pF.

Cheers

Phil Hobbs

There are two commonly given values for the capacitance between the

earth and the moon, 160uF and 3 uF. I think one is 2-wire capacitance

and the smaller one is 3-wire.

Where is the universe's ground lug?

pcdhSpamMeSenseless_at_electrooptical.net> wrote:

On 2/11/19 5:58 PM, RichD wrote:

Looking at network theory and the duality theorems,

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

--

Rich

There is. It's usually just called 'capacitance', unless you need to

distinguish it from self-capacitance.

A 1-cm radius isolated sphere has a self-capacitance of 1 cm (Gaussian

units), which is about 1.12 pF.

Cheers

Phil Hobbs

There are two commonly given values for the capacitance between the

earth and the moon, 160uF and 3 uF. I think one is 2-wire capacitance

and the smaller one is 3-wire.

Where is the universe's ground lug?

Well, there's some silly speculation about that we're living in a

simulation, in which case it would be Node 0. ;)

Cheers

Phil Hobbs

--

Dr Philip C D Hobbs

Principal Consultant

ElectroOptical Innovations LLC / Hobbs ElectroOptics

Optics, Electro-optics, Photonics, Analog Electronics

Briarcliff Manor NY 10510

http://electrooptical.net

http://hobbs-eo.com

Guest

Tue Feb 12, 2019 10:45 pm

On Tue, 12 Feb 2019 11:58:57 -0500, Phil Hobbs

<pcdhSpamMeSenseless_at_electrooptical.net> wrote:

On 2/12/19 11:47 AM, John Larkin wrote:

On Tue, 12 Feb 2019 10:33:31 -0500, Phil Hobbs

pcdhSpamMeSenseless_at_electrooptical.net> wrote:

On 2/11/19 5:58 PM, RichD wrote:

Looking at network theory and the duality theorems,

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

--

Rich

There is. It's usually just called 'capacitance', unless you need to

distinguish it from self-capacitance.

A 1-cm radius isolated sphere has a self-capacitance of 1 cm (Gaussian

units), which is about 1.12 pF.

Cheers

Phil Hobbs

There are two commonly given values for the capacitance between the

earth and the moon, 160uF and 3 uF. I think one is 2-wire capacitance

and the smaller one is 3-wire.

Where is the universe's ground lug?

Well, there's some silly speculation about that we're living in a

simulation, in which case it would be Node 0. ;)

Cheers

Phil Hobbs

On Tue, 12 Feb 2019 10:33:31 -0500, Phil Hobbs

pcdhSpamMeSenseless_at_electrooptical.net> wrote:

On 2/11/19 5:58 PM, RichD wrote:

Looking at network theory and the duality theorems,

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

--

Rich

There is. It's usually just called 'capacitance', unless you need to

distinguish it from self-capacitance.

A 1-cm radius isolated sphere has a self-capacitance of 1 cm (Gaussian

units), which is about 1.12 pF.

Cheers

Phil Hobbs

There are two commonly given values for the capacitance between the

earth and the moon, 160uF and 3 uF. I think one is 2-wire capacitance

and the smaller one is 3-wire.

Where is the universe's ground lug?

Well, there's some silly speculation about that we're living in a

simulation, in which case it would be Node 0. ;)

Cheers

Phil Hobbs

We could connect to the celestial sphere, the one with all the track

lights.

--

John Larkin Highland Technology, Inc

picosecond timing precision measurement

jlarkin att highlandtechnology dott com

http://www.highlandtechnology.com

Guest

Wed Feb 13, 2019 12:45 am

On 2/12/19 6:17 PM, RichD wrote:

On February 12, Phil Hobbs wrote:

Looking at network theory and the duality theorems,

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

There is. It's usually just called 'capacitance', unless you need to

distinguish it from self-capacitance.

I picture the analog of two isolated coils, magnetically

linked: two isolated capacitors, the flux of the 'primary'

transmits through the 'secondary'. Why no such device?

A 1-cm radius isolated sphere has a self-capacitance of 1 cm (Gaussian

units), which is about 1.12 pF.

Well, I have in mind your basic two plate capacitor.

I don't recall self-capacitance -

--

Rich

Looking at network theory and the duality theorems,

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

There is. It's usually just called 'capacitance', unless you need to

distinguish it from self-capacitance.

I picture the analog of two isolated coils, magnetically

linked: two isolated capacitors, the flux of the 'primary'

transmits through the 'secondary'. Why no such device?

A 1-cm radius isolated sphere has a self-capacitance of 1 cm (Gaussian

units), which is about 1.12 pF.

Well, I have in mind your basic two plate capacitor.

I don't recall self-capacitance -

--

Rich

What you're describing is precisely the mutual capacitance. It's the

change of the charge on plate 1 due to the change in voltage on plate 2.

Cheers

Phil Hobbs

--

Dr Philip C D Hobbs

Principal Consultant

ElectroOptical Innovations LLC / Hobbs ElectroOptics

Optics, Electro-optics, Photonics, Analog Electronics

Briarcliff Manor NY 10510

http://electrooptical.net

http://hobbs-eo.com

Guest

Wed Feb 13, 2019 12:45 am

On February 12, Phil Hobbs wrote:

Looking at network theory and the duality theorems,

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

There is. It's usually just called 'capacitance', unless you need to

distinguish it from self-capacitance.

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

There is. It's usually just called 'capacitance', unless you need to

distinguish it from self-capacitance.

I picture the analog of two isolated coils, magnetically

linked: two isolated capacitors, the flux of the 'primary'

transmits through the 'secondary'. Why no such device?

A 1-cm radius isolated sphere has a self-capacitance of 1 cm (Gaussian

units), which is about 1.12 pF.

units), which is about 1.12 pF.

Well, I have in mind your basic two plate capacitor.

I don't recall self-capacitance -

--

Rich

Guest

Wed Feb 13, 2019 12:45 am

On February 12, John Larkin wrote:

Looking at network theory and the duality theorems,

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

There are two commonly given values for the capacitance between the

earth and the moon, 160uF and 3 uF. I think one is 2-wire capacitance

and the smaller one is 3-wire.

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

There are two commonly given values for the capacitance between the

earth and the moon, 160uF and 3 uF. I think one is 2-wire capacitance

and the smaller one is 3-wire.

2-wire, 3-wire?

Explicate please -

--

Rich

Guest

Wed Feb 13, 2019 2:45 am

On Tuesday, February 12, 2019 at 3:17:53 PM UTC-8, RichD wrote:

On February 12, Phil Hobbs wrote:

A 1-cm radius isolated sphere has a self-capacitance of 1 cm (Gaussian

units), which is about 1.12 pF.

Well, I have in mind your basic two plate capacitor.

I don't recall self-capacitance -

A 1-cm radius isolated sphere has a self-capacitance of 1 cm (Gaussian

units), which is about 1.12 pF.

Well, I have in mind your basic two plate capacitor.

I don't recall self-capacitance -

Self-capacitance is the capacitance of an object with respect to ground, when it is

in a large grounded box. An infinite box, ideally.

Guest

Wed Feb 13, 2019 3:45 am

On 2/12/19 8:14 PM, whit3rd wrote:

On Tuesday, February 12, 2019 at 3:17:53 PM UTC-8, RichD wrote:

On February 12, Phil Hobbs wrote:

A 1-cm radius isolated sphere has a self-capacitance of 1 cm (Gaussian

units), which is about 1.12 pF.

Well, I have in mind your basic two plate capacitor.

I don't recall self-capacitance -

Self-capacitance is the capacitance of an object with respect to ground, when it is

in a large grounded box. An infinite box, ideally.

On February 12, Phil Hobbs wrote:

A 1-cm radius isolated sphere has a self-capacitance of 1 cm (Gaussian

units), which is about 1.12 pF.

Well, I have in mind your basic two plate capacitor.

I don't recall self-capacitance -

Self-capacitance is the capacitance of an object with respect to ground, when it is

in a large grounded box. An infinite box, ideally.

Ground isn't necessary. An isolated conductor with a certain amount Q

of free charge on it will have an E field. The voltage V is minus the

line integral of E dot ds from the surface to infinity. The

self-capacitance is Q/V.

Cheers

Phil Hobbs

--

Dr Philip C D Hobbs

Principal Consultant

ElectroOptical Innovations LLC / Hobbs ElectroOptics

Optics, Electro-optics, Photonics, Analog Electronics

Briarcliff Manor NY 10510

http://electrooptical.net

http://hobbs-eo.com

Guest

Wed Feb 13, 2019 3:45 am

On Tuesday, February 12, 2019 at 10:33:40 AM UTC-5, Phil Hobbs wrote:

On 2/11/19 5:58 PM, RichD wrote:

Looking at network theory and the duality theorems,

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

--

Rich

There is. It's usually just called 'capacitance', unless you need to

distinguish it from self-capacitance.

A 1-cm radius isolated sphere has a self-capacitance of 1 cm (Gaussian

units), which is about 1.12 pF.

Looking at network theory and the duality theorems,

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

--

Rich

There is. It's usually just called 'capacitance', unless you need to

distinguish it from self-capacitance.

A 1-cm radius isolated sphere has a self-capacitance of 1 cm (Gaussian

units), which is about 1.12 pF.

Huh right, I had this picture of three hunks of stuff with various

inter-capacitances. But that starts with one hunk!

George H.

Cheers

Phil Hobbs

--

Dr Philip C D Hobbs

Principal Consultant

ElectroOptical Innovations LLC / Hobbs ElectroOptics

Optics, Electro-optics, Photonics, Analog Electronics

Briarcliff Manor NY 10510

http://electrooptical.net

http://hobbs-eo.com

Guest

Wed Feb 13, 2019 7:45 am

On Tue, 12 Feb 2019 15:12:11 -0800 (PST), RichD

<r_delaney2001_at_yahoo.com> wrote:

On February 12, John Larkin wrote:

Looking at network theory and the duality theorems,

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

There are two commonly given values for the capacitance between the

earth and the moon, 160uF and 3 uF. I think one is 2-wire capacitance

and the smaller one is 3-wire.

2-wire, 3-wire?

Explicate please -

Looking at network theory and the duality theorems,

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

There are two commonly given values for the capacitance between the

earth and the moon, 160uF and 3 uF. I think one is 2-wire capacitance

and the smaller one is 3-wire.

2-wire, 3-wire?

Explicate please -

https://www.dropbox.com/s/ir45h6qd8gjryl0/2wire_3wire.JPG?dl=0

The 3-wire measurement ignores Cy and Cz.

If the moon moved away from earth, Cem would approach zero, but Ceu

and Cmu wouldn't change.

Most good c-meters will do 3-wire measurement, which allows a small

cap to be measured at the ends of coaxial cables.

--

John Larkin Highland Technology, Inc

lunatic fringe electronics

Guest

Wed Feb 13, 2019 7:45 am

On Tue, 12 Feb 2019 17:55:41 -0800 (PST), George Herold

<gherold_at_teachspin.com> wrote:

On Tuesday, February 12, 2019 at 10:33:40 AM UTC-5, Phil Hobbs wrote:

On 2/11/19 5:58 PM, RichD wrote:

Looking at network theory and the duality theorems,

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

--

Rich

There is. It's usually just called 'capacitance', unless you need to

distinguish it from self-capacitance.

A 1-cm radius isolated sphere has a self-capacitance of 1 cm (Gaussian

units), which is about 1.12 pF.

Huh right, I had this picture of three hunks of stuff with various

inter-capacitances. But that starts with one hunk!

George H.

On 2/11/19 5:58 PM, RichD wrote:

Looking at network theory and the duality theorems,

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

--

Rich

There is. It's usually just called 'capacitance', unless you need to

distinguish it from self-capacitance.

A 1-cm radius isolated sphere has a self-capacitance of 1 cm (Gaussian

units), which is about 1.12 pF.

Huh right, I had this picture of three hunks of stuff with various

inter-capacitances. But that starts with one hunk!

George H.

Just get a ball bearing floating in space and throw electrons at it.

--

John Larkin Highland Technology, Inc

lunatic fringe electronics

Guest

Wed Feb 13, 2019 4:45 pm

On Wednesday, February 13, 2019 at 12:56:49 AM UTC-5, John Larkin wrote:

On Tue, 12 Feb 2019 15:12:11 -0800 (PST), RichD

r_delaney2001_at_yahoo.com> wrote:

On February 12, John Larkin wrote:

Looking at network theory and the duality theorems,

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

There are two commonly given values for the capacitance between the

earth and the moon, 160uF and 3 uF. I think one is 2-wire capacitance

and the smaller one is 3-wire.

2-wire, 3-wire?

Explicate please -

https://www.dropbox.com/s/ir45h6qd8gjryl0/2wire_3wire.JPG?dl=0

The 3-wire measurement ignores Cy and Cz.

If the moon moved away from earth, Cem would approach zero, but Ceu

and Cmu wouldn't change.

Most good c-meters will do 3-wire measurement, which allows a small

cap to be measured at the ends of coaxial cables.

r_delaney2001_at_yahoo.com> wrote:

On February 12, John Larkin wrote:

Looking at network theory and the duality theorems,

why is there no mutual capacitance? i.e. electric

flux linkages, symmetric to mutual inductance and B flux.

There are two commonly given values for the capacitance between the

earth and the moon, 160uF and 3 uF. I think one is 2-wire capacitance

and the smaller one is 3-wire.

2-wire, 3-wire?

Explicate please -

https://www.dropbox.com/s/ir45h6qd8gjryl0/2wire_3wire.JPG?dl=0

The 3-wire measurement ignores Cy and Cz.

If the moon moved away from earth, Cem would approach zero, but Ceu

and Cmu wouldn't change.

Most good c-meters will do 3-wire measurement, which allows a small

cap to be measured at the ends of coaxial cables.

OK we should be able to work out the earth-moon capacitance as a

physics problem.

Here it is using method of images.

http://www.iue.tuwien.ac.at/phd/wasshuber/node77.html

(Hmm that is for sphere's of equal radius.)

As a first approximation we could guess that the Earth's C to the

universe is decreased by the ratio of the field lines that hit the

moon, to all of them... Which is pi*R_moon ^2/ (4*pi*Dist_E-M^2)

R_earth ~6.4 x10^6 m C_earth ~ 640 uF

R_moon ~1.7 x10^6 m

and Dist_E-M ~3.8x10^8 m.

Putting that all in.. and hopefully making no mistakes I get a drcrease

of 5x10^-6 or C_e-m ~3,200 pF .... 3.2 nF

What was your number for C_e-m?

George H.

Of course this is going to only be true at low frequency...

Speed of light and all.

--

John Larkin Highland Technology, Inc

lunatic fringe electronics

elektroda.net NewsGroups Forum Index - Electronic for beginners - **mutual capacitance?**