On Fri, 3 May 2013 07:30:44 -0700 (PDT), dagmargoodboat@yahoo.com wrote:>On May 3, 6:14�am, John Fields <jfie...@austininstruments.com> wrote: >> On Thu, 02 May 2013 17:54:47 -0700, John Larkin wrote: > >> As for the caps themselves, it seems lemonade could be made from >> lemons in that some use could be made of the parametric quality of the >> dielectric. For instance, that of a tuning element in an oscillator. >> >> Or, perhaps, a voltage tunable filter? >> >> A modulator? >> >> An attenuator? >> >> But - in your quest for beauty and truth - I'm sure you've already >> thought of those, at least, but remained silent for some good reason >> beyond the reach of the rest of us mere mortals. > >No, actually, John suggested a parametric oscillator and several other >applications. > >e.g. https://groups.google.com/group/sci.electronics.design/msg/1257d50b7385046e?hl=enI still haven't decided whether it's possible to make an unpumped oscillator based on "negative capacitance" C:V behavior. It's probably impossible since I don't think anyone has done it. I can maybe use conservation of energy to prove it can't be done. Pumped parametric amps and oscillators (using varicap diodes) are old hat; they were more popular around 1960, when transistors were still slow. 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/SubHarmonic.jpg This is a classic diode frequency multiplier, but it halves the frequency instead of doubling it. Conversion efficiency is impressively bad. -- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
Crapacitors
Started by ●May 2, 2013
Reply by ●May 3, 20132013-05-03
Reply by ●May 3, 20132013-05-03
On Thu, 2 May 2013 18:42:09 -0700 (PDT), George Herold <gherold@teachspin.com> wrote:>On May 2, 6:05�pm, John Larkin <jlar...@highlandtechnology.com> wrote: >> On Thu, 2 May 2013 12:31:43 -0700 (PDT), dagmargoodb...@yahoo.com >> wrote: >> >> >4.7uF 6.3V X5R >> >dC = -70% @ 6VDC (!!) >> > �http://psearch.murata.com/capacitor/product/GRM188R60J475ME19%23.pdf >> >> >James >> >> It's like a tantalum cap rated for X volts, with recommendation to >> never use it at X volts. >> >> (I actually use tantalum caps at rated voltage *if* there's not much >> charging current available. Otherwise, X/3 is about right.) >> >> -- >> >> John Larkin � � � � Highland Technology, Inc >> >> jlarkin at highlandtechnology dot comhttp://www.highlandtechnology.com >> >> Precision electronic instrumentation >> Picosecond-resolution Digital Delay and Pulse generators >> Custom laser drivers and controllers >> Photonics and fiberoptic TTL data links >> VME thermocouple, LVDT, synchro � acquisition and simulation > >I've got this audio amp that runs off 15 volts. >But I've told people you can stick upto 40V into it. >(as long as it doesn't over heat.) >The IC's are good to 60V (I think, LM675?) but I've only got 50V tants >as bypass C's. I should do a mod to 100V tants. Someone will want >more V. > >George H.Tants across supply rails are mini-detonators. Current through the cap, C di/dt, can ignite them. Use aluminums. https://dl.dropboxusercontent.com/u/53724080/Parts/Caps/Bang.jpg https://dl.dropboxusercontent.com/u/53724080/Parts/Caps/Fried_Tant_1.JPG -- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
Reply by ●May 3, 20132013-05-03
On Fri, 03 May 2013 13:43:44 -0500, Tim Wescott <tim@seemywebsite.com> wrote:>On Thu, 02 May 2013 12:31:43 -0700, dagmargoodboat wrote: > >> 4.7uF 6.3V X5R >> dC = -70% @ 6VDC (!!) >> http://psearch.murata.com/capacitor/product/GRM188R60J475ME19%23.pdf > >So I can build a resonant 33-60Hz VFO that only needs a 0-6V command >voltage (assuming I can find a 4.7H coil), and you say that's a BAD thing? > >Think of all the cool microwave techniques that can now be brought down >to base band!It will make a damned fine temperature sensor, too. -- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
Reply by ●May 3, 20132013-05-03
On May 3, 1:43=A0pm, Tim Wescott <t...@seemywebsite.com> wrote:> On Thu, 02 May 2013 12:31:43 -0700, dagmargoodboat wrote: > > 4.7uF 6.3V X5R > > dC =3D -70% @ 6VDC (!!) > > =A0http://psearch.murata.com/capacitor/product/GRM188R60J475ME19%23.pdf > > So I can build a resonant 33-60Hz VFO that only needs a 0-6V command > voltage (assuming I can find a 4.7H coil), and you say that's a BAD thing=?> > Think of all the cool microwave techniques that can now be brought down > to base band!Not just baseband -- scouting Digi-Key, you can get Y5V down to 10nF. There's surely something this would be really good for, but in ten years I haven't thought of it yet. (Plenty of ideas for VCOs, resonant tanks, etc, but no killer apps.) It might be handy for tuning the tanks of one of these resonant wireless energy schemes--crapacitors + inductors makes a handy tunable, low-loss energy storage. -- Cheers, James Arthur
Reply by ●May 3, 20132013-05-03
On 2013-05-03 22:39, John Larkin wrote:> On Fri, 3 May 2013 07:30:44 -0700 (PDT), dagmargoodboat@yahoo.com > wrote: > >> On May 3, 6:14 am, John Fields <jfie...@austininstruments.com> wrote: >>> On Thu, 02 May 2013 17:54:47 -0700, John Larkin wrote: >> >>> As for the caps themselves, it seems lemonade could be made from >>> lemons in that some use could be made of the parametric quality of the >>> dielectric. For instance, that of a tuning element in an oscillator. >>> >>> Or, perhaps, a voltage tunable filter? >>> >>> A modulator? >>> >>> An attenuator? >>> >>> But - in your quest for beauty and truth - I'm sure you've already >>> thought of those, at least, but remained silent for some good reason >>> beyond the reach of the rest of us mere mortals. >> >> No, actually, John suggested a parametric oscillator and several other >> applications. >> >> e.g. https://groups.google.com/group/sci.electronics.design/msg/1257d50b7385046e?hl=en > > I still haven't decided whether it's possible to make an unpumped > oscillator based on "negative capacitance" C:V behavior. It's probably > impossible since I don't think anyone has done it. I can maybe use > conservation of energy to prove it can't be done. Pumped parametric > amps and oscillators (using varicap diodes) are old hat; they were > more popular around 1960, when transistors were still slow. > > 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/SubHarmonic.jpg > > This is a classic diode frequency multiplier, but it halves the > frequency instead of doubling it. Conversion efficiency is > impressively bad. > > >Interesting gadget. Just about what I asked for some time ago. Cheers! Jeroen Belleman
Reply by ●May 3, 20132013-05-03
On May 3, 3:39=A0pm, John Larkin <jlar...@highlandtechnology.com> wrote:> On Fri, 3 May 2013 07:30:44 -0700 (PDT), dagmargoodb...@yahoo.com > wrote: > > > > >On May 3, 6:14 am, John Fields <jfie...@austininstruments.com> wrote: > >> On Thu, 02 May 2013 17:54:47 -0700, John Larkin wrote: > > >> As for the caps themselves, it seems lemonade could be made from > >> lemons in that some use could be made of the parametric quality of the > >> dielectric. For instance, that of a tuning element in an oscillator. > > >> Or, perhaps, a voltage tunable filter? > > >> A modulator? > > >> An attenuator? > > >> But - in your quest for beauty and truth - I'm sure you've already > >> thought of those, at least, but remained silent for some good reason > >> beyond the reach of the rest of us mere mortals. > > >No, actually, John suggested a parametric oscillator and several other > >applications. > > >e.g.https://groups.google.com/group/sci.electronics.design/msg/1257d50b7=3...> > I still haven't decided whether it's possible to make an unpumped > oscillator based on "negative capacitance" C:V behavior. It's probably > impossible since I don't think anyone has done it. I can maybe use > conservation of energy to prove it can't be done. Pumped parametric > amps and oscillators (using varicap diodes) are old hat; they were > more popular around 1960, when transistors were still slow. > > 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). -- Cheers, James Arthur
Reply by ●May 3, 20132013-05-03
John Larkin <jlarkin@highlandtechnology.com> wrote:> On Thu, 2 May 2013 18:42:09 -0700 (PDT), George Herold > <gherold@teachspin.com> wrote: > >>On May 2, 6:05?pm, John Larkin <jlar...@highlandtechnology.com> wrote: >>> On Thu, 2 May 2013 12:31:43 -0700 (PDT), dagmargoodb...@yahoo.com >>> wrote: >>> >>> >4.7uF 6.3V X5R >>> >dC = -70% @ 6VDC (!!) >>> > ?http://psearch.murata.com/capacitor/product/GRM188R60J475ME19%23.pdf >>> >>> >James >>> >>> It's like a tantalum cap rated for X volts, with recommendation to >>> never use it at X volts. >>> >>> (I actually use tantalum caps at rated voltage *if* there's not much >>> charging current available. Otherwise, X/3 is about right.) >>> >>> -- >>> >>> John Larkin ? ? ? ? Highland Technology, Inc >>> >>> jlarkin at highlandtechnology dot comhttp://www.highlandtechnology.com >>> >>> Precision electronic instrumentation >>> Picosecond-resolution Digital Delay and Pulse generators >>> Custom laser drivers and controllers >>> Photonics and fiberoptic TTL data links >>> VME thermocouple, LVDT, synchro ? acquisition and simulation >> >>I've got this audio amp that runs off 15 volts. >>But I've told people you can stick upto 40V into it. >>(as long as it doesn't over heat.) >>The IC's are good to 60V (I think, LM675?) but I've only got 50V tants >>as bypass C's. I should do a mod to 100V tants. Someone will want >>more V. >> >>George H. > > Tants across supply rails are mini-detonators. Current through the > cap, C di/dt, can ignite them. Use aluminums. > > https://dl.dropboxusercontent.com/u/53724080/Parts/Caps/Bang.jpg > > https://dl.dropboxusercontent.com/u/53724080/Parts/Caps/Fried_Tant_1.JPGthey are pretty ungraceful about failure. I'm sort of surprised nobody makes internally fused tantalums.
Reply by ●May 3, 20132013-05-03
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: >> >> >> >>> On May 3, 6:14 am, John Fields <jfie...@austininstruments.com> wrote: >>>> On Thu, 02 May 2013 17:54:47 -0700, John Larkin wrote: >> >>>> As for the caps themselves, it seems lemonade could be made from >>>> lemons in that some use could be made of the parametric quality of the >>>> dielectric. For instance, that of a tuning element in an oscillator. >> >>>> Or, perhaps, a voltage tunable filter? >> >>>> A modulator? >> >>>> An attenuator? >> >>>> But - in your quest for beauty and truth - I'm sure you've already >>>> thought of those, at least, but remained silent for some good reason >>>> beyond the reach of the rest of us mere mortals. >> >>> No, actually, John suggested a parametric oscillator and several other >>> applications. >> >>> e.g.https://groups.google.com/group/sci.electronics.design/msg/1257d50b73... >> >> I still haven't decided whether it's possible to make an unpumped >> oscillator based on "negative capacitance" C:V behavior. It's probably >> impossible since I don't think anyone has done it. I can maybe use >> conservation of energy to prove it can't be done. Pumped parametric >> amps and oscillators (using varicap diodes) are old hat; they were >> more popular around 1960, when transistors were still slow. >> >> 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. There is an optical domain equivalent gadget that fascinates the quantum theory crowd since quite some time already. It also has an impressively poor conversion efficiency: A BBO crystal. I've been looking for a simple passive circuit with similar behaviour. This appears to qualify. Jeroen Belleman
Reply by ●May 3, 20132013-05-03
On Fri, 3 May 2013 07:30:44 -0700 (PDT), dagmargoodboat@yahoo.com wrote:>On May 3, 6:14�am, John Fields <jfie...@austininstruments.com> wrote: >> On Thu, 02 May 2013 17:54:47 -0700, John Larkin wrote: > >> As for the caps themselves, it seems lemonade could be made from >> lemons in that some use could be made of the parametric quality of the >> dielectric. For instance, that of a tuning element in an oscillator. >> >> Or, perhaps, a voltage tunable filter? >> >> A modulator? >> >> An attenuator? >> >> But - in your quest for beauty and truth - I'm sure you've already >> thought of those, at least, but remained silent for some good reason >> beyond the reach of the rest of us mere mortals. > >No, actually, John suggested a parametric oscillator and several other >applications. > >e.g. https://groups.google.com/group/sci.electronics.design/msg/1257d50b7385046e?hl=en--- I missed those; thanks for the reality check. -- JF
Reply by ●May 3, 20132013-05-03
On May 3, 4:40=A0pm, Jeroen <jer...@nospam.please> wrote:> On 2013-05-03 23:23, dagmargoodb...@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: > > >>> On May 3, 6:14 am, John Fields <jfie...@austininstruments.com> wrote: > >>>> On Thu, 02 May 2013 17:54:47 -0700, John Larkin wrote: > > >>>> As for the caps themselves, it seems lemonade could be made from > >>>> lemons in that some use could be made of the parametric quality of t=he> >>>> dielectric. For instance, that of a tuning element in an oscillator. > > >>>> Or, perhaps, a voltage tunable filter? > > >>>> A modulator? > > >>>> An attenuator? > > >>>> But - in your quest for beauty and truth - I'm sure you've already > >>>> thought of those, at least, but remained silent for some good reason > >>>> beyond the reach of the rest of us mere mortals. > > >>> No, actually, John suggested a parametric oscillator and several othe=r> >>> applications. > > >>> e.g.https://groups.google.com/group/sci.electronics.design/msg/1257d5=0b73...> > >> I still haven't decided whether it's possible to make an unpumped > >> oscillator based on "negative capacitance" C:V behavior. It's probably > >> impossible since I don't think anyone has done it. I can maybe use > >> conservation of energy to prove it can't be done. Pumped parametric > >> amps and oscillators (using varicap diodes) are old hat; they were > >> more popular around 1960, when transistors were still slow. > > >> 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. =A0Looks 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.Which is exactly why it's ripe for green (or green for ripening), so to speak.> 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.Replacing John's schottky with a Y5V capacitor gives the same results, for similar reasons. You can try it with a varactor in LTSpice. I just made a /3. The resonant energy reference wasn't entirely frivolous: this circuit points out pretty well the exact challenges of wireless resonant transfer in pragmatic detail. With ideal parts, the weak transfer- coupling isn't a problem since all the un-transferred energy just sloshes around un-wasted in a perfect tank circuit--there aren't any ohmic losses. In reality, there are ohmic losses, and that kills it.> There is an optical domain equivalent gadget that fascinates the > quantum theory crowd since quite some time already. It also has > an impressively poor conversion efficiency: A BBO crystal. > I've been looking for a simple passive circuit with similar > behaviour. This appears to qualify.The world of optics and atoms is a different matter entirely; there you have all sorts of nearly ideal components. -- Cheers, James Arthur
