On 2013-05-19 03:22, josephkk wrote:
> On Tue, 07 May 2013 08:45:54 +0200, Jeroen Belleman <jeroen@nospam.please>
> wrote:
> 
>> On 2013-05-07 06:39, josephkk wrote:
>>> On Fri, 03 May 2013 23:40:10 +0200, Jeroen <jeroen@nospam.please> wrote:
>>>
>>>> On 2013-05-03 23:23, dagmargoodboat@yahoo.com wrote:
>>>>> On May 3, 3:39 pm, John Larkin <jlar...@highlandtechnology.com> wrote:
>>>>>> On Fri, 3 May 2013 07:30:44 -0700 (PDT), dagmargoodb...@yahoo.com
>>>>>> wrote:
>>>>>> I did manage to sumulate a frequency divider of sorts, really a
>>>>>> subcycle parametric oscillator, based on the C:V curve of a diode. It
>>>>>> should work with a ceramic cap, too. But it's still pumped, not
>>>>>> self-oscillating.
>>>>>>
>>>>>> https://dl.dropboxusercontent.com/u/53724080/Circuits/Oscillators/Sub...
>>>>>>
>>>>>> This is a classic diode frequency multiplier, but it halves the
>>>>>> frequency instead of doubling it. Conversion efficiency is
>>>>>> impressively bad.
>>>>>
>>>>> Yes, very impressively bad.  Looks like fodder for a green grant--it
>>>>> could be sooo much better with just a little invest-mint(tm).
>>>>
>>>> No one said it was useful for energy conversion.
>>>>
>>>> It's interesting, because normally non-linearity will only produce
>>>> harmonics, multiples, of the input frequency. This one also produces
>>>> sub-harmonics, at half the frequency in this case, just using a
>>>> single passive non-linear element.
>>>>
>>>> Jeroen Belleman
>>>
>>> Wow, but the half frequency output is soo poor.  I think i can do better.
>>> If i can figure it properly the ouput waveform will be much better and i
>>> won't need a VCVS to "hide" an required amplifier to get it to be barely
>>> usable.
>>>
>>> ?-)
>>>
>>
>> Please do. That would be interesting.
>>
>> Jeroen Belleman
> 
> My first two ideas didn't work out.
> 
> ?-(

Thank you for trying. I believe simple non-linearity is not enough.
A region of negative differential impedance is probably necessary,
or some sort of storage effect. Either way, one needs a bifurcation
in its phase space trajectory somewhere. Sinple non-linearity doesn't
do that.

I don't know what to make of John's results then. I should look into
this in some more detail. So many projects, so little time...

Jeroen Belleman

On Tue, 07 May 2013 08:45:54 +0200, Jeroen Belleman =
<jeroen@nospam.please>
wrote:

>On 2013-05-07 06:39, josephkk wrote:
>> On Fri, 03 May 2013 23:40:10 +0200, Jeroen <jeroen@nospam.please> =
wrote:
>>
>>> On 2013-05-03 23:23, dagmargoodboat@yahoo.com wrote:
>>>> On May 3, 3:39 pm, John Larkin <jlar...@highlandtechnology.com> =
wrote:
>>>>> On Fri, 3 May 2013 07:30:44 -0700 (PDT), dagmargoodb...@yahoo.com
>>>>> wrote:
>>>>> I did manage to sumulate a frequency divider of sorts, really a
>>>>> subcycle parametric oscillator, based on the C:V curve of a diode. =
It
>>>>> should work with a ceramic cap, too. But it's still pumped, not
>>>>> self-oscillating.
>>>>>
>>>>> =
https://dl.dropboxusercontent.com/u/53724080/Circuits/Oscillators/Sub...
>>>>>
>>>>> This is a classic diode frequency multiplier, but it halves the
>>>>> frequency instead of doubling it. Conversion efficiency is
>>>>> impressively bad.
>>>>
>>>> Yes, very impressively bad.  Looks like fodder for a green grant--it
>>>> could be sooo much better with just a little invest-mint(tm).
>>>
>>> No one said it was useful for energy conversion.
>>>
>>> It's interesting, because normally non-linearity will only produce
>>> harmonics, multiples, of the input frequency. This one also produces
>>> sub-harmonics, at half the frequency in this case, just using a
>>> single passive non-linear element.
>>>
>>> Jeroen Belleman
>>
>> Wow, but the half frequency output is soo poor.  I think i can do =
better.
>> If i can figure it properly the ouput waveform will be much better and=
 i
>> won't need a VCVS to "hide" an required amplifier to get it to be =
barely
>> usable.
>>
>> ?-)
>>
>
>Please do. That would be interesting.
>
>Jeroen Belleman

My first two ideas didn't work out.

?-(

On Mon, 06 May 2013 22:25:06 -0700, John Larkin wrote:

> Does anybody have an LT Spice script that includes the sort of grossly
> nonlinear cap that we've been discussing here?

Modeling nonlinear capacitors is fairly trivial. I know of several ways of
doing it. Most are irritatingly slow.

However, they don't adequately model the behavior of a Y5V ceramic. I did
some detailed measurements recently. Small signal AC capacitance versus DC
bias can be accurately modeled with a 5th order polynomial. However, stored
charge versus applied DC, measured with an electrometer, follows a totally
different curve, almost linear, nearly the nominal capacitance.

Put another way, we have a "slow" capacitance, and a "fast" one, which are
quite different. I need to investigate C versus f, next.

LTspice's nonlinear capacitance model (Q=f(V)) doesn't appear to work
with polynomials, at least in .ac analyses BTW.

Pspice capacitance model has quadratic voltage coefficients, which LTspice
barfs at.

-- 
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)

On Thu, 09 May 2013 09:22:02 -0700, John Larkin wrote:

> Good c-meters apply a small ac voltage, millivolts, and measure the small
> resulting ac current. They put DC bias on top of that.

Better C meters have variable ac voltage.

-- 
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)

On Fri, 10 May 2013 18:31:22 -0700, josephkk <joseph_barrett@sbcglobal.net>
wrote:

>On Wed, 08 May 2013 21:52:21 -0700, John Larkin
><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>
>>
>>>>George did it!
>>>
>>>And unlike you he stood up and admitted it.
>>>
>>>?-)
>>
>>Got anything interesting to say about capacitors?
>>
>You are very reactive, just like a good capacitor.
>
>?-)

I'll take that for a "no."


-- 

John Larkin                  Highland Technology Inc
www.highlandtechnology.com   jlarkin at highlandtechnology dot com   

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME  analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

On Wed, 08 May 2013 21:52:21 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

>
>>>George did it!
>>
>>And unlike you he stood up and admitted it.
>>
>>?-)
>
>Got anything interesting to say about capacitors?
>
You are very reactive, just like a good capacitor.

?-)

On Thu, 9 May 2013 07:19:28 -0700 (PDT), George Herold <gherold@teachspin.com>
wrote:

>On May 9, 10:15&#4294967295;am, dagmargoodb...@yahoo.com wrote:
>> On May 9, 10:03&#4294967295;am, George Herold <gher...@teachspin.com> wrote:
>>
>>
>>
>>
>>
>> > On May 9, 9:04&#4294967295;am, George Herold <gher...@teachspin.com> wrote:
>>
>> > > On May 9, 5:58&#4294967295;am, Mr Stonebeach <r...@wmail.fi> wrote:
>>
>> > > > On 9 touko, 00:36, John Fields <jfie...@austininstruments.com> wrote:
>>
>> > > > > On Wed, 08 May 2013 07:12:45 -0700, John Larkin
>> > > > > >Non-constant c with change in V *IS* capacitance nonlinearity.
>>
>> > > > > Actually, no.
>> > > > > Constant C with change in V doesn't say anything about the capacitor's
>> > > > > linearity, since C isn't changing.
>> > > > > Perhaps what you meant to say was that non-constant _change_ in
>> > > > > capacitance for a constant _change_ in voltage defines the capacitor's
>> > > > > nonlinearity?
>>
>> > > > &#4294967295; I think the definition JL uses, is standard - i.e. that a capacitor
>> > > > as
>> > > > a default has a linear charge-voltage relationship, and the constant
>> > > > of proportionality is C, the capacitance.
>>
>> > > > &#4294967295; This relates to the large subset of more general electric circuits,
>> > > > namely *linear* circuits, which are much simpler to treat
>> > > > mathematically than general circuits. For instance, the superposition
>> > > > principle applies, which is one consequence of the fact that network
>> > > > equations can be Laplace transformed
>> > > > into s-domain without invoking convolutions and other mathematical
>> > > > nastieties.
>>
>> > > > &#4294967295; In order a network to be linear one, its circuit elements must be
>> > > > linear elements, i.e. resistors with the linear I-V relation,
>> > > > capacitors
>> > > > with the linear Q-V relation, inductors with the linear phi-I
>> > > > relation,
>> > > > and so on [*].
>>
>> > > > &#4294967295; It is unfortunate that the constant of proportionality, C, is called
>> > > > "capacitance" because it sounds so similar to "capacitor" that
>> > > > one might indeed think that it is the linear C-to-something (maybe
>> > > > voltage) relation which defines the the linear capacitor. However, it
>> > > > is the linear Q-V relationship which ties the capacitor to the family
>> > > > of linear circuit elements, which we know and love, not the linear
>> > > > C-V relationship.
>>
>> > > > What JF wants to call the linear capacitor, might in general usage
>> > > > be called a linear *varactor*, obeying the linear relation
>> > > > C = C0 + k_C * V, which would imply Q = C0*V + 1/2*k_C*V^2 .
>> > > > But then there is a risk someone begins to call the constant of
>> > > > proportionality k_C the varactance, which sounds a lot like
>> > > > "varactor"...
>>
>> > > Nice, I might have written that with a minus sign,
>> > > &#4294967295;C = C0 - k_C * V,
>>
>> > > > > >It means that Q <> C * V
>>
>> > > > > Total nonsense.
>> > > > > Q is always equal to C * V.
>>
>> > > > &#4294967295; There are two possible definitions one might use, when moving
>> > > > outside the realm where the C was originally defined (the linear
>> > > > circuit theory): Fields uses the definition C = Q / V, whereas Larkin
>> > > > seems to use C = dQ / dV . In the linear case the two coincide.
>> > > > If someone continues to use the linear theory concept of
>> > > > "capacitance"
>> > > > in the nonlinear case, this suggests that he/she may want to
>> > > > linearize
>> > > > the nonlinear circuit for small signals at some dc setpoint. If so,
>> > > > Larkin's definition is the correct one to use.
>>
>> > > Interesting.. so I wonder which definition the manufacturers use?
>> > > Differential or do they measure how much charge it takes to get to
>> > > some voltage?
>>
>> > > If I had some of these crapacitors I could try a measurement.
>>
>> I've got a few reels, but I can't remember where!
>>
>> > Just plotting numbers from some of the previously posted data
>> > sheets.
>> > It looks like it has to be the differential definition. &#4294967295;(otherwise I
>> > get C*V products that are constant or even decreasing as the voltage
>> > is increased.)
>>
>> The mfrs.clearly use C=dQ/dV. &#4294967295;Capacitance meters do too.
>>
>> --
>> Cheers,
>> James Arthur- Hide quoted text -
>>
>> - Show quoted text -
>
>Yeah don't bother with any measurment.  The link from JL (other
>thread) to clifton labs also shows that it's dQ/dV.
>
>George H.

Good c-meters apply a small ac voltage, millivolts, and measure the small
resulting ac current. They put DC bias on top of that.

Of course, people can choose to define C = Q/V like they choose to define R =
E/I and always be right.

I did use c and C somewhere above, as the incremental and gross capacitances.

The Boonton 72 series are great c-meters, available used fairly cheap.


-- 

John Larkin                  Highland Technology Inc
www.highlandtechnology.com   jlarkin at highlandtechnology dot com   

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME  analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

On May 9, 10:15=A0am, dagmargoodb...@yahoo.com wrote:
> On May 9, 10:03=A0am, George Herold <gher...@teachspin.com> wrote:
>
>
>
>
>
> > On May 9, 9:04=A0am, George Herold <gher...@teachspin.com> wrote:
>
> > > On May 9, 5:58=A0am, Mr Stonebeach <r...@wmail.fi> wrote:
>
> > > > On 9 touko, 00:36, John Fields <jfie...@austininstruments.com> wrot=
e:
>
> > > > > On Wed, 08 May 2013 07:12:45 -0700, John Larkin
> > > > > >Non-constant c with change in V *IS* capacitance nonlinearity.
>
> > > > > Actually, no.
> > > > > Constant C with change in V doesn't say anything about the capaci=
tor's
> > > > > linearity, since C isn't changing.
> > > > > Perhaps what you meant to say was that non-constant _change_ in
> > > > > capacitance for a constant _change_ in voltage defines the capaci=
tor's
> > > > > nonlinearity?
>
> > > > =A0 I think the definition JL uses, is standard - i.e. that a capac=
itor
> > > > as
> > > > a default has a linear charge-voltage relationship, and the constan=
t
> > > > of proportionality is C, the capacitance.
>
> > > > =A0 This relates to the large subset of more general electric circu=
its,
> > > > namely *linear* circuits, which are much simpler to treat
> > > > mathematically than general circuits. For instance, the superpositi=
on
> > > > principle applies, which is one consequence of the fact that networ=
k
> > > > equations can be Laplace transformed
> > > > into s-domain without invoking convolutions and other mathematical
> > > > nastieties.
>
> > > > =A0 In order a network to be linear one, its circuit elements must =
be
> > > > linear elements, i.e. resistors with the linear I-V relation,
> > > > capacitors
> > > > with the linear Q-V relation, inductors with the linear phi-I
> > > > relation,
> > > > and so on [*].
>
> > > > =A0 It is unfortunate that the constant of proportionality, C, is c=
alled
> > > > "capacitance" because it sounds so similar to "capacitor" that
> > > > one might indeed think that it is the linear C-to-something (maybe
> > > > voltage) relation which defines the the linear capacitor. However, =
it
> > > > is the linear Q-V relationship which ties the capacitor to the fami=
ly
> > > > of linear circuit elements, which we know and love, not the linear
> > > > C-V relationship.
>
> > > > What JF wants to call the linear capacitor, might in general usage
> > > > be called a linear *varactor*, obeying the linear relation
> > > > C =3D C0 + k_C * V, which would imply Q =3D C0*V + 1/2*k_C*V^2 .
> > > > But then there is a risk someone begins to call the constant of
> > > > proportionality k_C the varactance, which sounds a lot like
> > > > "varactor"...
>
> > > Nice, I might have written that with a minus sign,
> > > =A0C =3D C0 - k_C * V,
>
> > > > > >It means that Q <> C * V
>
> > > > > Total nonsense.
> > > > > Q is always equal to C * V.
>
> > > > =A0 There are two possible definitions one might use, when moving
> > > > outside the realm where the C was originally defined (the linear
> > > > circuit theory): Fields uses the definition C =3D Q / V, whereas La=
rkin
> > > > seems to use C =3D dQ / dV . In the linear case the two coincide.
> > > > If someone continues to use the linear theory concept of
> > > > "capacitance"
> > > > in the nonlinear case, this suggests that he/she may want to
> > > > linearize
> > > > the nonlinear circuit for small signals at some dc setpoint. If so,
> > > > Larkin's definition is the correct one to use.
>
> > > Interesting.. so I wonder which definition the manufacturers use?
> > > Differential or do they measure how much charge it takes to get to
> > > some voltage?
>
> > > If I had some of these crapacitors I could try a measurement.
>
> I've got a few reels, but I can't remember where!
>
> > Just plotting numbers from some of the previously posted data
> > sheets.
> > It looks like it has to be the differential definition. =A0(otherwise I
> > get C*V products that are constant or even decreasing as the voltage
> > is increased.)
>
> The mfrs.clearly use C=3DdQ/dV. =A0Capacitance meters do too.
>
> --
> Cheers,
> James Arthur- Hide quoted text -
>
> - Show quoted text -

Yeah don't bother with any measurment.  The link from JL (other
thread) to clifton labs also shows that it's dQ/dV.

George H.

On May 9, 10:03=A0am, George Herold <gher...@teachspin.com> wrote:
> On May 9, 9:04=A0am, George Herold <gher...@teachspin.com> wrote:
>
>
>
>
>
>
>
>
>
> > On May 9, 5:58=A0am, Mr Stonebeach <r...@wmail.fi> wrote:
>
> > > On 9 touko, 00:36, John Fields <jfie...@austininstruments.com> wrote:
>
> > > > On Wed, 08 May 2013 07:12:45 -0700, John Larkin
> > > > >Non-constant c with change in V *IS* capacitance nonlinearity.
>
> > > > Actually, no.
> > > > Constant C with change in V doesn't say anything about the capacito=
r's
> > > > linearity, since C isn't changing.
> > > > Perhaps what you meant to say was that non-constant _change_ in
> > > > capacitance for a constant _change_ in voltage defines the capacito=
r's
> > > > nonlinearity?
>
> > > =A0 I think the definition JL uses, is standard - i.e. that a capacit=
or
> > > as
> > > a default has a linear charge-voltage relationship, and the constant
> > > of proportionality is C, the capacitance.
>
> > > =A0 This relates to the large subset of more general electric circuit=
s,
> > > namely *linear* circuits, which are much simpler to treat
> > > mathematically than general circuits. For instance, the superposition
> > > principle applies, which is one consequence of the fact that network
> > > equations can be Laplace transformed
> > > into s-domain without invoking convolutions and other mathematical
> > > nastieties.
>
> > > =A0 In order a network to be linear one, its circuit elements must be
> > > linear elements, i.e. resistors with the linear I-V relation,
> > > capacitors
> > > with the linear Q-V relation, inductors with the linear phi-I
> > > relation,
> > > and so on [*].
>
> > > =A0 It is unfortunate that the constant of proportionality, C, is cal=
led
> > > "capacitance" because it sounds so similar to "capacitor" that
> > > one might indeed think that it is the linear C-to-something (maybe
> > > voltage) relation which defines the the linear capacitor. However, it
> > > is the linear Q-V relationship which ties the capacitor to the family
> > > of linear circuit elements, which we know and love, not the linear
> > > C-V relationship.
>
> > > What JF wants to call the linear capacitor, might in general usage
> > > be called a linear *varactor*, obeying the linear relation
> > > C =3D C0 + k_C * V, which would imply Q =3D C0*V + 1/2*k_C*V^2 .
> > > But then there is a risk someone begins to call the constant of
> > > proportionality k_C the varactance, which sounds a lot like
> > > "varactor"...
>
> > Nice, I might have written that with a minus sign,
> > =A0C =3D C0 - k_C * V,
>
> > > > >It means that Q <> C * V
>
> > > > Total nonsense.
> > > > Q is always equal to C * V.
>
> > > =A0 There are two possible definitions one might use, when moving
> > > outside the realm where the C was originally defined (the linear
> > > circuit theory): Fields uses the definition C =3D Q / V, whereas Lark=
in
> > > seems to use C =3D dQ / dV . In the linear case the two coincide.
> > > If someone continues to use the linear theory concept of
> > > "capacitance"
> > > in the nonlinear case, this suggests that he/she may want to
> > > linearize
> > > the nonlinear circuit for small signals at some dc setpoint. If so,
> > > Larkin's definition is the correct one to use.
>
> > Interesting.. so I wonder which definition the manufacturers use?
> > Differential or do they measure how much charge it takes to get to
> > some voltage?
>
> > If I had some of these crapacitors I could try a measurement.

I've got a few reels, but I can't remember where!

> Just plotting numbers from some of the previously posted data
> sheets.
> It looks like it has to be the differential definition. =A0(otherwise I
> get C*V products that are constant or even decreasing as the voltage
> is increased.)

The mfrs.clearly use C=3DdQ/dV.  Capacitance meters do too.

--
Cheers,
James Arthur

On May 9, 9:04=A0am, George Herold <gher...@teachspin.com> wrote:
> On May 9, 5:58=A0am, Mr Stonebeach <r...@wmail.fi> wrote:
>
>
>
>
>
> > On 9 touko, 00:36, John Fields <jfie...@austininstruments.com> wrote:
>
> > > On Wed, 08 May 2013 07:12:45 -0700, John Larkin
> > > >Non-constant c with change in V *IS* capacitance nonlinearity.
>
> > > Actually, no.
> > > Constant C with change in V doesn't say anything about the capacitor'=
s
> > > linearity, since C isn't changing.
> > > Perhaps what you meant to say was that non-constant _change_ in
> > > capacitance for a constant _change_ in voltage defines the capacitor'=
s
> > > nonlinearity?
>
> > =A0 I think the definition JL uses, is standard - i.e. that a capacitor
> > as
> > a default has a linear charge-voltage relationship, and the constant
> > of proportionality is C, the capacitance.
>
> > =A0 This relates to the large subset of more general electric circuits,
> > namely *linear* circuits, which are much simpler to treat
> > mathematically than general circuits. For instance, the superposition
> > principle applies, which is one consequence of the fact that network
> > equations can be Laplace transformed
> > into s-domain without invoking convolutions and other mathematical
> > nastieties.
>
> > =A0 In order a network to be linear one, its circuit elements must be
> > linear elements, i.e. resistors with the linear I-V relation,
> > capacitors
> > with the linear Q-V relation, inductors with the linear phi-I
> > relation,
> > and so on [*].
>
> > =A0 It is unfortunate that the constant of proportionality, C, is calle=
d
> > "capacitance" because it sounds so similar to "capacitor" that
> > one might indeed think that it is the linear C-to-something (maybe
> > voltage) relation which defines the the linear capacitor. However, it
> > is the linear Q-V relationship which ties the capacitor to the family
> > of linear circuit elements, which we know and love, not the linear
> > C-V relationship.
>
> > What JF wants to call the linear capacitor, might in general usage
> > be called a linear *varactor*, obeying the linear relation
> > C =3D C0 + k_C * V, which would imply Q =3D C0*V + 1/2*k_C*V^2 .
> > But then there is a risk someone begins to call the constant of
> > proportionality k_C the varactance, which sounds a lot like
> > "varactor"...
>
> Nice, I might have written that with a minus sign,
> =A0C =3D C0 - k_C * V,
>
>
>
>
>
>
>
> > > >It means that Q <> C * V
>
> > > Total nonsense.
> > > Q is always equal to C * V.
>
> > =A0 There are two possible definitions one might use, when moving
> > outside the realm where the C was originally defined (the linear
> > circuit theory): Fields uses the definition C =3D Q / V, whereas Larkin
> > seems to use C =3D dQ / dV . In the linear case the two coincide.
> > If someone continues to use the linear theory concept of
> > "capacitance"
> > in the nonlinear case, this suggests that he/she may want to
> > linearize
> > the nonlinear circuit for small signals at some dc setpoint. If so,
> > Larkin's definition is the correct one to use.
>
> Interesting.. so I wonder which definition the manufacturers use?
> Differential or do they measure how much charge it takes to get to
> some voltage?
>
> If I had some of these crapacitors I could try a measurement.
>
> George H.

Just plotting numbers from some of the previously posted data
sheets.
It looks like it has to be the differential definition.  (otherwise I
get C*V products that are constant or even decreasing as the voltage
is increased.)

George H.
>
>
>
>
>
> > Regards,
> > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 Mikko
>
> > [*] Recall that Q and Phi are actually just shorthand for integrals
> > of
> > the system variables Q=3DInt(I dt) and phi=3DInt(V dt), so
> > the confusion is about which are the dynamic variables and which
> > are the coefficients in the governing (linear) differential equations.
> > And, what is the most fruitful nomenclature to use, when
> > expanding into the nonlinear diff. eq. realm.- Hide quoted text -
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -