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Lambda diode gyrator, pt 2

Started by bitrex July 9, 2019
On Tuesday, July 9, 2019 at 8:44:07 PM UTC-4, bitrex wrote:
> On 7/9/19 8:27 PM, George Herold wrote: > > On Tuesday, July 9, 2019 at 2:23:15 PM UTC-4, John Larkin wrote: > >> On Tue, 9 Jul 2019 14:14:06 -0400, bitrex <user@example.net> wrote: > >> > >>> On 7/9/19 12:04 PM, John Larkin wrote: > >>>> On Tue, 9 Jul 2019 12:02:02 -0400, bitrex <user@example.net> wrote: > >>>> > >>>>> With a more appropriate op amp and better choice of operating > >>>>> point for the diode it looks like the lambda diode load really does > >>>>> provide a significant bandwidth improvement as compared to a resistive > >>>>> load for the gyrator in the high-pass configuration, about 4x, here: > >>>>> > >>>>> <https://imgur.com/a/NZM9lBl> > >>>>> > >>>>> While preserving the low-frequency response > >>>> > >>>> Why not a capacitor and a resistor as a highpass? That will go to GHz. > >>>> > >>>> > >>>> > >>>> > >>> > >>> The "L"-R highpass is the simplest example I could think of for > >>> experimenting with using the LD this way. > >>> > >>> I can't of a great real-world use case for a LR gyrator high-pass > >>> structure off the top of my head, maybe someone knows of one > >> > > > > Well for me it was that can get good caps, (and inductors, are more > > complicated.) > > > > I like the state variable filter... and better opamps, make it better. > > (mostly 100k Hz and below.) > > > > Speaking of caps. Is there a good, (good means mostly > > low dissipation factor, though size/ price also matters.) > > 1 uF cap? At 0.1 uF I'm using cog ceramics. > > Maybe I should just stack up 0.1uF ceramics and add some > > more R? > > (I'm using some polystyrene automotive ones from DK > > in the current design, but DF is not great.) > > > > George H. > > Which are the ones you're using now, specifically? 1uF polystyrene caps > sounds pricey and large! > > The PCB mount plastic caps I've used in that range before are these > metalized polyester EVOX/KEMET units: > > <https://www.mouser.com/datasheet/2/212/F3294_MMK-1101858.pdf> > > about $1 in singles, 50 cent in hundreds for the 63VDC type. the loss > tangent is rated at <= 0.005 @ 1kHz.
Sorry, they are PET not polystyrene... my mistake. https://www.digikey.com/products/en?keywords=495-1119-nd GH
On Wed, 10 Jul 2019 10:23:57 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

>On 7/9/19 2:18 PM, John Larkin wrote: >> On Tue, 9 Jul 2019 14:14:06 -0400, bitrex <user@example.net> wrote: >> >>> On 7/9/19 12:04 PM, John Larkin wrote: >>>> On Tue, 9 Jul 2019 12:02:02 -0400, bitrex <user@example.net> wrote: >>>> >>>>> With a more appropriate op amp and better choice of operating >>>>> point for the diode it looks like the lambda diode load really does >>>>> provide a significant bandwidth improvement as compared to a resistive >>>>> load for the gyrator in the high-pass configuration, about 4x, here: >>>>> >>>>> <https://imgur.com/a/NZM9lBl> >>>>> >>>>> While preserving the low-frequency response >>>> >>>> Why not a capacitor and a resistor as a highpass? That will go to GHz. >>>> >>>> >>>> >>>> >>> >>> The "L"-R highpass is the simplest example I could think of for >>> experimenting with using the LD this way. >>> >>> I can't of a great real-world use case for a LR gyrator high-pass >>> structure off the top of my head, maybe someone knows of one >> >> I never understood the appeal of gyrators. One opamp, or one LC, makes >> a second-order section. >> >> Maybe they have some advantages for on-chip analog filters. JT used to >> like them. >> >> > >The main benefit of op amp gyrators is low component sensitivity--it's >0.5, just like a passive LC. I've never used a built-up one either. > >On the other hand, a cap multiplier is also a gyrator. ;) > >Cheers > >Phil Hobbs
I designed the Winch Control Intercommunications Subsystem for the C5A. Part of it was a very c-multiplier-like circuit to filter the DC supply for the audio parts. There is a clever RC circuit that has a gain of over 1, and I discovered it by accident; my c-multiplier oscillated. -- John Larkin Highland Technology, Inc lunatic fringe electronics
On 7/10/19 11:00 AM, George Herold wrote:
> On Tuesday, July 9, 2019 at 8:44:07 PM UTC-4, bitrex wrote: >> On 7/9/19 8:27 PM, George Herold wrote: >>> On Tuesday, July 9, 2019 at 2:23:15 PM UTC-4, John Larkin wrote: >>>> On Tue, 9 Jul 2019 14:14:06 -0400, bitrex <user@example.net> wrote: >>>> >>>>> On 7/9/19 12:04 PM, John Larkin wrote: >>>>>> On Tue, 9 Jul 2019 12:02:02 -0400, bitrex <user@example.net> wrote: >>>>>> >>>>>>> With a more appropriate op amp and better choice of operating >>>>>>> point for the diode it looks like the lambda diode load really does >>>>>>> provide a significant bandwidth improvement as compared to a resistive >>>>>>> load for the gyrator in the high-pass configuration, about 4x, here: >>>>>>> >>>>>>> <https://imgur.com/a/NZM9lBl> >>>>>>> >>>>>>> While preserving the low-frequency response >>>>>> >>>>>> Why not a capacitor and a resistor as a highpass? That will go to GHz. >>>>>> >>>>>> >>>>>> >>>>>> >>>>> >>>>> The "L"-R highpass is the simplest example I could think of for >>>>> experimenting with using the LD this way. >>>>> >>>>> I can't of a great real-world use case for a LR gyrator high-pass >>>>> structure off the top of my head, maybe someone knows of one >>>> >>> >>> Well for me it was that can get good caps, (and inductors, are more >>> complicated.) >>> >>> I like the state variable filter... and better opamps, make it better. >>> (mostly 100k Hz and below.) >>> >>> Speaking of caps. Is there a good, (good means mostly >>> low dissipation factor, though size/ price also matters.) >>> 1 uF cap? At 0.1 uF I'm using cog ceramics. >>> Maybe I should just stack up 0.1uF ceramics and add some >>> more R? >>> (I'm using some polystyrene automotive ones from DK >>> in the current design, but DF is not great.) >>> >>> George H. >> >> Which are the ones you're using now, specifically? 1uF polystyrene caps >> sounds pricey and large! >> >> The PCB mount plastic caps I've used in that range before are these >> metalized polyester EVOX/KEMET units: >> >> <https://www.mouser.com/datasheet/2/212/F3294_MMK-1101858.pdf> >> >> about $1 in singles, 50 cent in hundreds for the 63VDC type. the loss >> tangent is rated at <= 0.005 @ 1kHz. > > Sorry, they are PET not polystyrene... my mistake. > https://www.digikey.com/products/en?keywords=495-1119-nd > > GH >
That makes sense. Raw polystyrene is an almost ideal dielectric except that the Dk is low and can't be made that thin. I have some 0.22uF polystyrene caps and they're really big and probably cost a lot (can't remember what I paid for 'em exactly, though.)
On 7/10/19 11:00 AM, George Herold wrote:
> On Tuesday, July 9, 2019 at 8:44:07 PM UTC-4, bitrex wrote: >> On 7/9/19 8:27 PM, George Herold wrote: >>> On Tuesday, July 9, 2019 at 2:23:15 PM UTC-4, John Larkin wrote: >>>> On Tue, 9 Jul 2019 14:14:06 -0400, bitrex <user@example.net> wrote: >>>> >>>>> On 7/9/19 12:04 PM, John Larkin wrote: >>>>>> On Tue, 9 Jul 2019 12:02:02 -0400, bitrex <user@example.net> wrote: >>>>>> >>>>>>> With a more appropriate op amp and better choice of operating >>>>>>> point for the diode it looks like the lambda diode load really does >>>>>>> provide a significant bandwidth improvement as compared to a resistive >>>>>>> load for the gyrator in the high-pass configuration, about 4x, here: >>>>>>> >>>>>>> <https://imgur.com/a/NZM9lBl> >>>>>>> >>>>>>> While preserving the low-frequency response >>>>>> >>>>>> Why not a capacitor and a resistor as a highpass? That will go to GHz. >>>>>> >>>>>> >>>>>> >>>>>> >>>>> >>>>> The "L"-R highpass is the simplest example I could think of for >>>>> experimenting with using the LD this way. >>>>> >>>>> I can't of a great real-world use case for a LR gyrator high-pass >>>>> structure off the top of my head, maybe someone knows of one >>>> >>> >>> Well for me it was that can get good caps, (and inductors, are more >>> complicated.) >>> >>> I like the state variable filter... and better opamps, make it better. >>> (mostly 100k Hz and below.) >>> >>> Speaking of caps. Is there a good, (good means mostly >>> low dissipation factor, though size/ price also matters.) >>> 1 uF cap? At 0.1 uF I'm using cog ceramics. >>> Maybe I should just stack up 0.1uF ceramics and add some >>> more R? >>> (I'm using some polystyrene automotive ones from DK >>> in the current design, but DF is not great.) >>> >>> George H. >> >> Which are the ones you're using now, specifically? 1uF polystyrene caps >> sounds pricey and large! >> >> The PCB mount plastic caps I've used in that range before are these >> metalized polyester EVOX/KEMET units: >> >> <https://www.mouser.com/datasheet/2/212/F3294_MMK-1101858.pdf> >> >> about $1 in singles, 50 cent in hundreds for the 63VDC type. the loss >> tangent is rated at <= 0.005 @ 1kHz. > > Sorry, they are PET not polystyrene... my mistake. > https://www.digikey.com/products/en?keywords=495-1119-nd > > GH >
Polypropylene is generally OK. IIRC Win has some stuff on dielectrics in AoE3. Polystyrene caps went away because it melts at 100C, which makes reflow soldering sort of hard unless you're using Wood's metal or something. 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
On Wednesday, July 10, 2019 at 12:37:13 PM UTC-4, Phil Hobbs wrote:
> On 7/10/19 11:00 AM, George Herold wrote: > > On Tuesday, July 9, 2019 at 8:44:07 PM UTC-4, bitrex wrote: > >> On 7/9/19 8:27 PM, George Herold wrote: > >>> On Tuesday, July 9, 2019 at 2:23:15 PM UTC-4, John Larkin wrote: > >>>> On Tue, 9 Jul 2019 14:14:06 -0400, bitrex <user@example.net> wrote: > >>>> > >>>>> On 7/9/19 12:04 PM, John Larkin wrote: > >>>>>> On Tue, 9 Jul 2019 12:02:02 -0400, bitrex <user@example.net> wrote: > >>>>>> > >>>>>>> With a more appropriate op amp and better choice of operating > >>>>>>> point for the diode it looks like the lambda diode load really does > >>>>>>> provide a significant bandwidth improvement as compared to a resistive > >>>>>>> load for the gyrator in the high-pass configuration, about 4x, here: > >>>>>>> > >>>>>>> <https://imgur.com/a/NZM9lBl> > >>>>>>> > >>>>>>> While preserving the low-frequency response > >>>>>> > >>>>>> Why not a capacitor and a resistor as a highpass? That will go to GHz. > >>>>>> > >>>>>> > >>>>>> > >>>>>> > >>>>> > >>>>> The "L"-R highpass is the simplest example I could think of for > >>>>> experimenting with using the LD this way. > >>>>> > >>>>> I can't of a great real-world use case for a LR gyrator high-pass > >>>>> structure off the top of my head, maybe someone knows of one > >>>> > >>> > >>> Well for me it was that can get good caps, (and inductors, are more > >>> complicated.) > >>> > >>> I like the state variable filter... and better opamps, make it better. > >>> (mostly 100k Hz and below.) > >>> > >>> Speaking of caps. Is there a good, (good means mostly > >>> low dissipation factor, though size/ price also matters.) > >>> 1 uF cap? At 0.1 uF I'm using cog ceramics. > >>> Maybe I should just stack up 0.1uF ceramics and add some > >>> more R? > >>> (I'm using some polystyrene automotive ones from DK > >>> in the current design, but DF is not great.) > >>> > >>> George H. > >> > >> Which are the ones you're using now, specifically? 1uF polystyrene caps > >> sounds pricey and large! > >> > >> The PCB mount plastic caps I've used in that range before are these > >> metalized polyester EVOX/KEMET units: > >> > >> <https://www.mouser.com/datasheet/2/212/F3294_MMK-1101858.pdf> > >> > >> about $1 in singles, 50 cent in hundreds for the 63VDC type. the loss > >> tangent is rated at <= 0.005 @ 1kHz. > > > > Sorry, they are PET not polystyrene... my mistake. > > https://www.digikey.com/products/en?keywords=495-1119-nd > > > > GH > > > > Polypropylene is generally OK. IIRC Win has some stuff on dielectrics > in AoE3. Polystyrene caps went away because it melts at 100C, which > makes reflow soldering sort of hard unless you're using Wood's metal or > something.
Yeah we use to buy more polypropylene caps. But now all the lower voltage ones seem to have gone away, so you are stuck with higher voltage (bigger) ones. I use more COG ceramics.. but they top out at ~ 0.1 uF. (just went searching DK again for large value cog ceramics) 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
On 10/07/2019 6:15 pm, George Herold wrote:
> On Wednesday, July 10, 2019 at 12:37:13 PM UTC-4, Phil Hobbs wrote: >> On 7/10/19 11:00 AM, George Herold wrote: >>> On Tuesday, July 9, 2019 at 8:44:07 PM UTC-4, bitrex wrote: >>>> On 7/9/19 8:27 PM, George Herold wrote: >>>>> On Tuesday, July 9, 2019 at 2:23:15 PM UTC-4, John Larkin wrote: >>>>>> On Tue, 9 Jul 2019 14:14:06 -0400, bitrex <user@example.net> wrote: >>>>>> >>>>>>> On 7/9/19 12:04 PM, John Larkin wrote: >>>>>>>> On Tue, 9 Jul 2019 12:02:02 -0400, bitrex <user@example.net> wrote: >>>>>>>> >>>>>>>>> With a more appropriate op amp and better choice of operating >>>>>>>>> point for the diode it looks like the lambda diode load really does >>>>>>>>> provide a significant bandwidth improvement as compared to a resistive >>>>>>>>> load for the gyrator in the high-pass configuration, about 4x, here: >>>>>>>>> >>>>>>>>> <https://imgur.com/a/NZM9lBl> >>>>>>>>> >>>>>>>>> While preserving the low-frequency response >>>>>>>> >>>>>>>> Why not a capacitor and a resistor as a highpass? That will go to GHz. >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>> >>>>>>> The "L"-R highpass is the simplest example I could think of for >>>>>>> experimenting with using the LD this way. >>>>>>> >>>>>>> I can't of a great real-world use case for a LR gyrator high-pass >>>>>>> structure off the top of my head, maybe someone knows of one >>>>>> >>>>> >>>>> Well for me it was that can get good caps, (and inductors, are more >>>>> complicated.) >>>>> >>>>> I like the state variable filter... and better opamps, make it better. >>>>> (mostly 100k Hz and below.) >>>>> >>>>> Speaking of caps. Is there a good, (good means mostly >>>>> low dissipation factor, though size/ price also matters.) >>>>> 1 uF cap? At 0.1 uF I'm using cog ceramics. >>>>> Maybe I should just stack up 0.1uF ceramics and add some >>>>> more R? >>>>> (I'm using some polystyrene automotive ones from DK >>>>> in the current design, but DF is not great.) >>>>> >>>>> George H. >>>> >>>> Which are the ones you're using now, specifically? 1uF polystyrene caps >>>> sounds pricey and large! >>>> >>>> The PCB mount plastic caps I've used in that range before are these >>>> metalized polyester EVOX/KEMET units: >>>> >>>> <https://www.mouser.com/datasheet/2/212/F3294_MMK-1101858.pdf> >>>> >>>> about $1 in singles, 50 cent in hundreds for the 63VDC type. the loss >>>> tangent is rated at <= 0.005 @ 1kHz. >>> >>> Sorry, they are PET not polystyrene... my mistake. >>> https://www.digikey.com/products/en?keywords=495-1119-nd >>> >>> GH >>> >> >> Polypropylene is generally OK. IIRC Win has some stuff on dielectrics >> in AoE3. Polystyrene caps went away because it melts at 100C, which >> makes reflow soldering sort of hard unless you're using Wood's metal or >> something. > Yeah we use to buy more polypropylene caps. But now all the lower voltage > ones seem to have gone away, so you are stuck with higher voltage (bigger) > ones. I use more COG ceramics.. but they top out at ~ 0.1 uF. > (just went searching DK again for large value cog ceramics) > > 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 >
Polyphenylene Sulfide is also good as polyproylene at low volatges but try and get through-hole parts instead of SMD which can deliminate in reflow. piglet