On Aug 17, 10:11=A0pm, Phil Hobbs <pcdhSpamMeSensel...@electrooptical.net> wrote:> Spehro Pefhany wrote: > > > On Fri, 17 Aug 2012 15:06:02 -0400, Phil Hobbs > > <pcdhSpamMeSensel...@electrooptical.net> wrote: > > > >Yup. =A0Using some gnarly disc ceramic made for some pretty amusing IN=L.> > > >Cheers > > > >Phil Hobbs > > > Even polyester was none too good in that application. > > IIRC BITD I usually used polystyrene, and it seemed to work fine.Polypropylene is better. A colleague who did a serious dual slope A/D imported PTFE (Teflon) dielectric capacitors from the US, and still had to fudge his "dual slope" such that there was never very much voltage difference across the capacitor, but he was getting 20-bit accuracy. -- Bill sloman, Nijmegen
fast ramp follies
Started by ●August 14, 2012
Reply by ●August 17, 20122012-08-17
Reply by ●August 17, 20122012-08-17
Spehro Pefhany wrote:> > On Fri, 17 Aug 2012 16:11:01 -0400, Phil Hobbs > <pcdhSpamMeSenseless@electrooptical.net> wrote: > > >Spehro Pefhany wrote: > >> > >> On Fri, 17 Aug 2012 15:06:02 -0400, Phil Hobbs > >> <pcdhSpamMeSenseless@electrooptical.net> wrote: > >> > >> > > >> >Yup. Using some gnarly disc ceramic made for some pretty amusing INL. > >> > > >> >Cheers > >> > > >> >Phil Hobbs > >> > >> Even polyester was none too good in that application. > > > >IIRC BITD I usually used polystyrene, and it seemed to work fine. > > > >Cheers > > > >Phil Hobbs > > I would have thought PS caps would be too bulky in that size range. We > used PC (polycarbonate) where it mattered. > > I did a design that used a synthetic high-DA cap made from resistors > and relatively good caps in order to linearize a sensor. Nowadays we > tend to use micros for that, of course.Last time I used one was in about 1989, so I'm not 100% sure. However, a zillion $20 DPMs can't be wrong! 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 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
Reply by ●August 17, 20122012-08-17
On Aug 17, 10:46=A0pm, Spehro Pefhany <speffS...@interlogDOTyou.knowwhat> wrote:> On Fri, 17 Aug 2012 16:11:01 -0400, Phil Hobbs > > > > > > > > > > <pcdhSpamMeSensel...@electrooptical.net> wrote: > >Spehro Pefhany wrote: > > >> On Fri, 17 Aug 2012 15:06:02 -0400, Phil Hobbs > >> <pcdhSpamMeSensel...@electrooptical.net> wrote: > > >> >Yup. =A0Using some gnarly disc ceramic made for some pretty amusing I=NL.> > >> >Cheers > > >> >Phil Hobbs > > >> Even polyester was none too good in that application. > > >IIRC BITD I usually used polystyrene, and it seemed to work fine. > > >Cheers > > >Phil Hobbs > > I would have thought PS caps would be too bulky in that size range. We > used PC (polycarbonate) where it mattered.Polycarbonate was better than polyester, but not much. Polypropylene was quite a bit better than either, but bulkier, if not as bulky as polystyrene.> I did a design that used a synthetic high-DA cap made from resistors > and relatively good caps in order to linearize a sensor. Nowadays we > tend to use micros for that, of course.Now that's lateral thinking. -- Bill Sloman, Nijmegen
Reply by ●August 17, 20122012-08-17
On Fri, 17 Aug 2012 16:11:55 -0400, Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> wrote:>On Fri, 17 Aug 2012 15:06:02 -0400, Phil Hobbs ><pcdhSpamMeSenseless@electrooptical.net> wrote: > >> >>Yup. Using some gnarly disc ceramic made for some pretty amusing INL. >> >>Cheers >> >>Phil Hobbs > >Even polyester was none too good in that application.I got confused by a home-made dual slope that I designed that had, like, a 1% error. Somebody else thought to change the integrator cap from a mylar to a polycarb, and pretty much fixed it. Up to then, I figured that all film caps were alike. -- 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 ●August 17, 20122012-08-17
On Fri, 17 Aug 2012 10:23:14 -0700, John Larkin <jlarkin@highlandtechnology.com> wrote:> >I invented a pseudo-inductor once, for one of the C5A projects of my >youth. To get the impedance up, I bootstrapped the base of a >darlington from its own emitter with a double RC. It oscillated at >some low frequency, 10 Hz or something. I didn't realize it at the >time, but I'd stumbled onto that RCRC circuit that has voltage gain. I >fixed it without really understanding it. This was back in pre-Spice >days, when simulation was a chore. >A nit to pick, you aren't old enough to complain about pre-spice days, just not having access to it. I know, i am about your age and knew about spice in my early teens (my dad was an EE). Many years later i had my = own spice 2.6g derivative; must have been 25 to 30 years ago.> >--=20 > >John Larkin Highland Technology, Inc
Reply by ●August 18, 20122012-08-18
On Fri, 17 Aug 2012 19:38:35 -0700, josephkk <joseph_barrett@sbcglobal.net> wrote:>On Fri, 17 Aug 2012 10:23:14 -0700, John Larkin ><jlarkin@highlandtechnology.com> wrote: > >> >>I invented a pseudo-inductor once, for one of the C5A projects of my >>youth. To get the impedance up, I bootstrapped the base of a >>darlington from its own emitter with a double RC. It oscillated at >>some low frequency, 10 Hz or something. I didn't realize it at the >>time, but I'd stumbled onto that RCRC circuit that has voltage gain. I >>fixed it without really understanding it. This was back in pre-Spice >>days, when simulation was a chore. >> >A nit to pick, you aren't old enough to complain about pre-spice days, >just not having access to it. I know, i am about your age and knew about >spice in my early teens (my dad was an EE). Many years later i had my own >spice 2.6g derivative; must have been 25 to 30 years ago.I hate to brag about how old I am, but Spice was introduced to the world in 1973 http://en.wikipedia.org/wiki/SPICE#Origins I was simulating the throttle control system, turbine, propeller, and hull dynamics of the LASH ships in 1968, while I was still an undergrad at Tulane. I did initial sims on an HP9100 programmable calculator, but soon cut over to a PDP8i running the FOCAL interpretive language. http://www.pdp8.net/pdp8i/pdp8i.shtml>> >>-- >> >>John Larkin Highland Technology, Inc-- 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
Reply by ●August 18, 20122012-08-18
On Fri, 17 Aug 2012 19:38:35 -0700, josephkk <joseph_barrett@sbcglobal.net> wrote:> must have been 25 to 30 years ago.It shows.
Reply by ●August 18, 20122012-08-18
On Aug 18, 7:03=A0am, John Larkin <jjlar...@highNOTlandTHIStechnologyPART.com> wrote:> On Fri, 17 Aug 2012 19:38:35 -0700, josephkk > > > > > > > > > > <joseph_barr...@sbcglobal.net> wrote: > >On Fri, 17 Aug 2012 10:23:14 -0700, John Larkin > ><jlar...@highlandtechnology.com> wrote: > > >>I invented a pseudo-inductor once, for one of the C5A projects of my > >>youth. To get the impedance up, I bootstrapped the base of a > >>darlington from its own emitter with a double RC. It oscillated at > >>some low frequency, 10 Hz or something. I didn't realize it at the > >>time, but I'd stumbled onto that RCRC circuit that has voltage gain. I > >>fixed it without really understanding it. This was back in pre-Spice > >>days, when simulation was a chore. > > >A nit to pick, you aren't old enough to complain about pre-spice days, > >just not having access to it. =A0I know, i am about your age and knew ab=out> >spice in my early teens (my dad was an EE). =A0Many years later i had my=own> >spice 2.6g derivative; must have been 25 to 30 years ago. > > I hate to brag about how old I am, but Spice was introduced to the > world in 1973 > > http://en.wikipedia.org/wiki/SPICE#Origins > > I was simulating the throttle control system, turbine, propeller, and > hull dynamics of the LASH ships in 1968, while I was still an > undergrad at Tulane. I did initial sims on an HP9100 programmable > calculator, but soon cut over to a PDP8i running the FOCAL > interpretive language. > > http://www.pdp8.net/pdp8i/pdp8i.shtmlSure. My Ph.D. work included the numerical integration of a couple of differential equations to model the the thermal decomposition of nitrosyle bromide - I wrote the program in 1968, and embedded it in a non-linear least squares minimisation program that adjusted the rate constant of the chemical reaction (as well as the initial and final concentrations of NOBr) to fit the various chunks experimental data (collected with different starting conditions and at different temperatures). The experimental data was collected by an interrupt controlled PDP-8 - writing the program for that took a couple of weeks - while the data reduction adn curve ditting took place on a IBM 7040/44. I got to use the university's 7040/44 between 2:00am and 6:00am. The electronic engineers ran their simulation programs from 11.00pm to 2:00am - I used to sneak the occasional test run into their batches. Spice was just one variant of the simulation software that was being worked up at the time - it went on to rule the world, but it wasn't wildly different from the competition. -- Bill Sloman, Nijmegen
Reply by ●August 18, 20122012-08-18
On Aug 18, 8:03=A0am, John Larkin <jjlar...@highNOTlandTHIStechnologyPART.com> wrote:> I hate to brag about how old I am, but Spice was introduced to the > world in 1973Interesting, that's roughly the same time as my favourite simulator APLAC. I was under impression that SPICE would have been older. Regards, Mikko
Reply by ●August 18, 20122012-08-18
Bill Sloman wrote:> On Aug 18, 7:03 am, John Larkin > <jjlar...@highNOTlandTHIStechnologyPART.com> wrote: > >>On Fri, 17 Aug 2012 19:38:35 -0700, josephkk >> >> >> >> >> >> >> >> >> >><joseph_barr...@sbcglobal.net> wrote: >> >>>On Fri, 17 Aug 2012 10:23:14 -0700, John Larkin >>><jlar...@highlandtechnology.com> wrote: >> >>>>I invented a pseudo-inductor once, for one of the C5A projects of my >>>>youth. To get the impedance up, I bootstrapped the base of a >>>>darlington from its own emitter with a double RC. It oscillated at >>>>some low frequency, 10 Hz or something. I didn't realize it at the >>>>time, but I'd stumbled onto that RCRC circuit that has voltage gain. I >>>>fixed it without really understanding it. This was back in pre-Spice >>>>days, when simulation was a chore. >> >>>A nit to pick, you aren't old enough to complain about pre-spice days, >>>just not having access to it. I know, i am about your age and knew about >>>spice in my early teens (my dad was an EE). Many years later i had my own >>>spice 2.6g derivative; must have been 25 to 30 years ago. >> >>I hate to brag about how old I am, but Spice was introduced to the >>world in 1973 >> >>http://en.wikipedia.org/wiki/SPICE#Origins >> >>I was simulating the throttle control system, turbine, propeller, and >>hull dynamics of the LASH ships in 1968, while I was still an >>undergrad at Tulane. I did initial sims on an HP9100 programmable >>calculator, but soon cut over to a PDP8i running the FOCAL >>interpretive language. >> >>http://www.pdp8.net/pdp8i/pdp8i.shtml > > > Sure. My Ph.D. work included the numerical integration of a couple of > differential equations to model the the thermal decomposition of > nitrosyle bromide - I wrote the program in 1968, and embedded it in a > non-linear least squares minimisation program that adjusted the rate > constant of the chemical reaction (as well as the initial and final > concentrations of NOBr) to fit the various chunks experimental data > (collected with different starting conditions and at different > temperatures). > >With all the paper work you just claimed, how much from society did you rob over the years? How much did you actually contribute to make the world a better place? And how much did you actually work, period! No bother to answer, most of use already know.. Sounds like a lot of bull shit on paper if you ask me.. I too have paper work. But I keep it where it belongs, in the filing cabinet because as far as I am concern it does not help me in resolving issues from day to day and doing my job, a real job. The only Phd I brag about is the one in my tool shed. Jamie
