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WHOA! Negative Capacitor in LowPass

Started by Jim Thompson January 13, 2017
WHOA! Negative Capacitor in LowPass

See...

"NegCapacitor_Used_in_LowPass.png" on the S.E.D/Schematics Page of my
website.

Note the phase!

This was whipped up using idealized components... now to go back and
do it with OpAmps and see if it behaves.
		
                                        ...Jim Thompson
-- 
| James E.Thompson                                 |    mens     |
| Analog Innovations                               |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| STV, Queen Creek, AZ 85142    Skype: skypeanalog |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
On Fri, 13 Jan 2017 08:26:43 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

>WHOA! Negative Capacitor in LowPass > >See... > >"NegCapacitor_Used_in_LowPass.png" on the S.E.D/Schematics Page of my >website. > >Note the phase! > >This was whipped up using idealized components... now to go back and >do it with OpAmps and see if it behaves. > > ...Jim Thompson
Whoa! Again! Fails transient analysis, blows up... dreams of zero-phase dashed :-( ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 |
On Fri, 13 Jan 2017 08:36:55 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

>On Fri, 13 Jan 2017 08:26:43 -0700, Jim Thompson ><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: > >>WHOA! Negative Capacitor in LowPass >> >>See... >> >>"NegCapacitor_Used_in_LowPass.png" on the S.E.D/Schematics Page of my >>website. >> >>Note the phase! >> >>This was whipped up using idealized components... now to go back and >>do it with OpAmps and see if it behaves. >> >> ...Jim Thompson > >Whoa! Again! Fails transient analysis, blows up... dreams of >zero-phase dashed :-( > > ...Jim Thompson
Should of just tried a lowpass with C=-1nF without the active elements... that blows up as well.. which should be obvious if one just stops and thinks for one moment: I = -C*dV/dt Kaboom! ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 |
On Fri, 13 Jan 2017 08:26:43 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

>WHOA! Negative Capacitor in LowPass > >See... > >"NegCapacitor_Used_in_LowPass.png" on the S.E.D/Schematics Page of my >website. > >Note the phase! > >This was whipped up using idealized components... now to go back and >do it with OpAmps and see if it behaves. > > ...Jim Thompson
If you're just interested in network response, and not practical implememtation, LT Spice is happy to let you use negative r/l/c component values. -- John Larkin Highland Technology, Inc lunatic fringe electronics
On Fri, 13 Jan 2017 08:19:34 -0800, John Larkin
<jjlarkin@highlandtechnology.com> wrote:

>On Fri, 13 Jan 2017 08:26:43 -0700, Jim Thompson ><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: > >>WHOA! Negative Capacitor in LowPass >> >>See... >> >>"NegCapacitor_Used_in_LowPass.png" on the S.E.D/Schematics Page of my >>website. >> >>Note the phase! >> >>This was whipped up using idealized components... now to go back and >>do it with OpAmps and see if it behaves. >> >> ...Jim Thompson > >If you're just interested in network response, and not practical >implememtation, LT Spice is happy to let you use negative r/l/c >component values.
Yep. PSpice also. But I got so wrapped up in my amusement with the active-element negative capacitor that I failed to check the simple C=-1nF approach... until the active-element approach produced giga-volts when submitted to transient analysis. (But it'll pass a dotAC analysis... which leads you down the garden path :-) ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 |
On Fri, 13 Jan 2017 10:19:54 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

>On Fri, 13 Jan 2017 08:19:34 -0800, John Larkin ><jjlarkin@highlandtechnology.com> wrote: > >>On Fri, 13 Jan 2017 08:26:43 -0700, Jim Thompson >><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >> >>>WHOA! Negative Capacitor in LowPass >>> >>>See... >>> >>>"NegCapacitor_Used_in_LowPass.png" on the S.E.D/Schematics Page of my >>>website. >>> >>>Note the phase! >>> >>>This was whipped up using idealized components... now to go back and >>>do it with OpAmps and see if it behaves. >>> >>> ...Jim Thompson >> >>If you're just interested in network response, and not practical >>implememtation, LT Spice is happy to let you use negative r/l/c >>component values. > >Yep. PSpice also. But I got so wrapped up in my amusement with the >active-element negative capacitor that I failed to check the simple >C=-1nF approach... until the active-element approach produced >giga-volts when submitted to transient analysis.
Amateur. My negative-c circuits make teravolts. -- John Larkin Highland Technology, Inc lunatic fringe electronics
On Fri, 13 Jan 2017 09:51:36 -0800, John Larkin
<jjlarkin@highlandtechnology.com> wrote:

>On Fri, 13 Jan 2017 10:19:54 -0700, Jim Thompson ><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: > >>On Fri, 13 Jan 2017 08:19:34 -0800, John Larkin >><jjlarkin@highlandtechnology.com> wrote: >> >>>On Fri, 13 Jan 2017 08:26:43 -0700, Jim Thompson >>><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>> >>>>WHOA! Negative Capacitor in LowPass >>>> >>>>See... >>>> >>>>"NegCapacitor_Used_in_LowPass.png" on the S.E.D/Schematics Page of my >>>>website. >>>> >>>>Note the phase! >>>> >>>>This was whipped up using idealized components... now to go back and >>>>do it with OpAmps and see if it behaves. >>>> >>>> ...Jim Thompson >>> >>>If you're just interested in network response, and not practical >>>implememtation, LT Spice is happy to let you use negative r/l/c >>>component values. >> >>Yep. PSpice also. But I got so wrapped up in my amusement with the >>active-element negative capacitor that I failed to check the simple >>C=-1nF approach... until the active-element approach produced >>giga-volts when submitted to transient analysis. > >Amateur. My negative-c circuits make teravolts.
Sno-o-o-o-ort ;-) I have default gmin set at 1n which limits the "kick". ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I'm looking for work... see my website. Thinking outside the box to produce elegant solutions.
On 01/13/2017 11:10 AM, Jim Thompson wrote:
> On Fri, 13 Jan 2017 08:36:55 -0700, Jim Thompson > <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: > >> On Fri, 13 Jan 2017 08:26:43 -0700, Jim Thompson >> <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >> >>> WHOA! Negative Capacitor in LowPass >>> >>> See... >>> >>> "NegCapacitor_Used_in_LowPass.png" on the S.E.D/Schematics Page of my >>> website. >>> >>> Note the phase! >>> >>> This was whipped up using idealized components... now to go back and >>> do it with OpAmps and see if it behaves. >>> >>> ...Jim Thompson >> >> Whoa! Again! Fails transient analysis, blows up... dreams of >> zero-phase dashed :-( >> >> ...Jim Thompson > > Should of just tried a lowpass with C=-1nF without the active > elements... that blows up as well.. which should be obvious if one > just stops and thinks for one moment: > > I = -C*dV/dt > Kaboom! > > ...Jim Thompson >
Yup, those pesky lower half plane poles. ;) Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
On Fri, 13 Jan 2017 13:20:51 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

>On 01/13/2017 11:10 AM, Jim Thompson wrote: >> On Fri, 13 Jan 2017 08:36:55 -0700, Jim Thompson >> <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >> >>> On Fri, 13 Jan 2017 08:26:43 -0700, Jim Thompson >>> <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>> >>>> WHOA! Negative Capacitor in LowPass >>>> >>>> See... >>>> >>>> "NegCapacitor_Used_in_LowPass.png" on the S.E.D/Schematics Page of my >>>> website. >>>> >>>> Note the phase! >>>> >>>> This was whipped up using idealized components... now to go back and >>>> do it with OpAmps and see if it behaves. >>>> >>>> ...Jim Thompson >>> >>> Whoa! Again! Fails transient analysis, blows up... dreams of >>> zero-phase dashed :-( >>> >>> ...Jim Thompson >> >> Should of just tried a lowpass with C=-1nF without the active >> elements... that blows up as well.. which should be obvious if one >> just stops and thinks for one moment: >> >> I = -C*dV/dt >> Kaboom! >> >> ...Jim Thompson >> >Yup, those pesky lower half plane poles. ;) > >Cheers > >Phil Hobbs
Yes ;-) ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I'm looking for work... see my website. Thinking outside the box... producing elegant solutions.
On 01/13/2017 12:19 PM, Jim Thompson wrote:
> On Fri, 13 Jan 2017 08:19:34 -0800, John Larkin > <jjlarkin@highlandtechnology.com> wrote: > >> On Fri, 13 Jan 2017 08:26:43 -0700, Jim Thompson >> <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >> >>> WHOA! Negative Capacitor in LowPass >>> >>> See... >>> >>> "NegCapacitor_Used_in_LowPass.png" on the S.E.D/Schematics Page of my >>> website. >>> >>> Note the phase! >>> >>> This was whipped up using idealized components... now to go back and >>> do it with OpAmps and see if it behaves. >>> >>> ...Jim Thompson >> >> If you're just interested in network response, and not practical >> implememtation, LT Spice is happy to let you use negative r/l/c >> component values. > > Yep. PSpice also. But I got so wrapped up in my amusement with the > active-element negative capacitor that I failed to check the simple > C=-1nF approach... until the active-element approach produced > giga-volts when submitted to transient analysis. > > (But it'll pass a dotAC analysis... which leads you down the garden > path :-) > > ...Jim Thompson >
There's a schematic floating around of a two op-amp circuit that synthesizes a floating negative inductor; so now one can make an LC ladder filter using all negative elements. See what it's like to live in the antimatter universe...