Twin T circuit wanted
in [Design]
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From: default on 8 Jun 2010 17:34 On Tue, 08 Jun 2010 13:47:58 -0700, Jim Thompson <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote: Sorry guys. I had no idea. I was just looking for a lazy shortcut, but to quote some western I saw a long time ago: "Why, Oh Why, Must there bee all this fight'n and kill'n?" (with a Southern twang) Philosophically, "Everyone you meet can teach you something." No one knows everything. The active is learning the passive is teaching. Suffer the fools - they will always know something you haven't learned. It isn't a contest, we all become fertilizer for another generation. and preaching is easy if you have no skin in the game, mea culpa - so have at it. --
From: dagmargoodboat on 8 Jun 2010 17:53 On Jun 8, 2:09 pm, John Larkin <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > On Tue, 8 Jun 2010 10:00:55 -0700 (PDT), dagmargoodb...(a)yahoo.com > wrote: > > > > >On Jun 8, 10:31 am, Jim Thompson <To-Email-Use-The-Envelope-I...(a)On-My- > >Web-Site.com> wrote: > >> On Mon, 07 Jun 2010 20:33:23 -0700, John Larkin<jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > > >> [snip] > > >> >This is kind of a cute circuit. I first designed it when I needed a > >> >very frequency and amplitude-stable sine wave to drive a Talyvel > >> >LVDT-like inclinometer, part of the Boresight Alignment Kit for the > >> >C5A. We had to measure level to arc-seconds of accuracy. > > >> >It's a transformer with a resonant tank in the collector and a > >> >positive feedback drive winding into the emitter. The emitter feedback > >> >is just a couple of tenths of a volt p-p. > > >> [snip] > > >> "designed"?? > > >> Quite _exactly_ like you'd find in common AM radios as the LO, once > >> transistors came upon the scene.... > > >>http://www.electronics-tutorials.com/receivers/rec-basic-fig1.gif > > >Cute, and familiar, yes, but that one doesn't have John's c-b > >conduction agc mechanism. That's a pretty neat feature--have you seen > >it elsewhere? > > He has a pretty inexact definition of "_exactly_" > > It seems to mean "not very similar at all." Easy boys. I've designed stuff myself only to find others had beat me to it, and I conversely invented a really neat frequency multiplier which Wenzel and a few others later came up with too. Mine was in mass production years before, but as far as they know they invented it. A year or two ago I thought I'd invented something worthy of a state secret, but Phil spit it out here later as a suggestion like it t'were nuthin... So, I'm always interested to know about those who've gone before me. -- Cheers, James Arthur
From: John Larkin on 8 Jun 2010 18:09 On Tue, 8 Jun 2010 14:53:04 -0700 (PDT), dagmargoodboat(a)yahoo.com wrote: >On Jun 8, 2:09�pm, John Larkin ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >> On Tue, 8 Jun 2010 10:00:55 -0700 (PDT), dagmargoodb...(a)yahoo.com >> wrote: >> >> >> >> >On Jun 8, 10:31 am, Jim Thompson <To-Email-Use-The-Envelope-I...(a)On-My- >> >Web-Site.com> wrote: >> >> On Mon, 07 Jun 2010 20:33:23 -0700, John Larkin<jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >> >> >> [snip] >> >> >> >This is kind of a cute circuit. I first designed it when I needed a >> >> >very frequency and amplitude-stable sine wave to drive a Talyvel >> >> >LVDT-like inclinometer, part of the Boresight Alignment Kit for the >> >> >C5A. We had to measure level to arc-seconds of accuracy. >> >> >> >It's a transformer with a resonant tank in the collector and a >> >> >positive feedback drive winding into the emitter. The emitter feedback >> >> >is just a couple of tenths of a volt p-p. >> >> >> [snip] >> >> >> "designed"?? >> >> >> Quite _exactly_ like you'd find in common AM radios as the LO, once >> >> transistors came upon the scene.... >> >> >>http://www.electronics-tutorials.com/receivers/rec-basic-fig1.gif >> >> >Cute, and familiar, yes, but that one doesn't have John's c-b >> >conduction agc mechanism. �That's a pretty neat feature--have you seen >> >it elsewhere? >> >> He has a pretty inexact definition of "_exactly_" >> >> It seems to mean "not very similar at all." > >Easy boys. I've designed stuff myself only to find others had beat me >to it, and I conversely invented a really neat frequency multiplier >which Wenzel and a few others later came up with too. Mine was in >mass production years before, but as far as they know they invented >it. I never claimed that nobody had done this before; how could I know that? I do claim that I hadn't seen it done before, nor since. And it's cute. Who invented it isn't important; cute is. The old radio thing that JT linked to is nothing like it. It uses a lot more parts and has classic 3-resistor class A biasing, among other differences. If I claimed that there was nitrogen in the air, he and JF would hack a Spice simulation and prove me wrong. Hell, if those old hens ever did come up with sound generator circuits, one would make pecking noises and the other would go "cluck." (How's that, rantwise?) > >A year or two ago I thought I'd invented something worthy of a state >secret, but Phil spit it out here later as a suggestion like it t'were >nuthin... He does that. He's not mortal like us. John
From: dagmargoodboat on 8 Jun 2010 19:04 On Jun 8, 5:09 pm, John Larkin <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > On Tue, 8 Jun 2010 14:53:04 -0700 (PDT), dagmargoodb...(a)yahoo.com > wrote: > > > > >On Jun 8, 2:09 pm, John Larkin > ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > >> On Tue, 8 Jun 2010 10:00:55 -0700 (PDT), dagmargoodb...(a)yahoo.com > >> wrote: > > >> >On Jun 8, 10:31 am, Jim Thompson <To-Email-Use-The-Envelope-I...(a)On-My- > >> >Web-Site.com> wrote: > >> >> On Mon, 07 Jun 2010 20:33:23 -0700, John Larkin<jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > > >> >> [snip] > > >> >> >This is kind of a cute circuit. I first designed it when I needed a > >> >> >very frequency and amplitude-stable sine wave to drive a Talyvel > >> >> >LVDT-like inclinometer, part of the Boresight Alignment Kit for the > >> >> >C5A. We had to measure level to arc-seconds of accuracy. > > >> >> >It's a transformer with a resonant tank in the collector and a > >> >> >positive feedback drive winding into the emitter. The emitter feedback > >> >> >is just a couple of tenths of a volt p-p. > > >> >> [snip] > > >> >> "designed"?? > > >> >> Quite _exactly_ like you'd find in common AM radios as the LO, once > >> >> transistors came upon the scene.... > > >> >>http://www.electronics-tutorials.com/receivers/rec-basic-fig1.gif > > >> >Cute, and familiar, yes, but that one doesn't have John's c-b > >> >conduction agc mechanism. That's a pretty neat feature--have you seen > >> >it elsewhere? > > >> He has a pretty inexact definition of "_exactly_" > > >> It seems to mean "not very similar at all." > > >Easy boys. I've designed stuff myself only to find others had beat me > >to it, and I conversely invented a really neat frequency multiplier > >which Wenzel and a few others later came up with too. Mine was in > >mass production years before, but as far as they know they invented > >it. > > I never claimed that nobody had done this before; how could I know > that? I do claim that I hadn't seen it done before, nor since. And > it's cute. Who invented it isn't important; cute is. > > The old radio thing that JT linked to is nothing like it. It uses a > lot more parts and has classic 3-resistor class A biasing, among other > differences. Yeah yeah, we all get that. The circuits speak for themselves. No need to poke a stick at Jim--he's a good 'ol grizzly bar, just grouchy. The whole country's grouchy, the people ill-at ease. Such are the times. [snip] > >A year or two ago I thought I'd invented something worthy of a state > >secret, but Phil spit it out here later as a suggestion like it t'were > >nuthin... > > He does that. He's not mortal like us. Of course not. He's a physicist. The really good ones don't bathe, either. -- Best regards, James
From: John Larkin on 8 Jun 2010 20:13
On Tue, 8 Jun 2010 16:04:33 -0700 (PDT), dagmargoodboat(a)yahoo.com wrote: >On Jun 8, 5:09�pm, John Larkin ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >> On Tue, 8 Jun 2010 14:53:04 -0700 (PDT), dagmargoodb...(a)yahoo.com >> wrote: >> >> >> >> >On Jun 8, 2:09�pm, John Larkin >> ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >> >> On Tue, 8 Jun 2010 10:00:55 -0700 (PDT), dagmargoodb...(a)yahoo.com >> >> wrote: >> >> >> >On Jun 8, 10:31 am, Jim Thompson <To-Email-Use-The-Envelope-I...(a)On-My- >> >> >Web-Site.com> wrote: >> >> >> On Mon, 07 Jun 2010 20:33:23 -0700, John Larkin<jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >> >> >> >> [snip] >> >> >> >> >This is kind of a cute circuit. I first designed it when I needed a >> >> >> >very frequency and amplitude-stable sine wave to drive a Talyvel >> >> >> >LVDT-like inclinometer, part of the Boresight Alignment Kit for the >> >> >> >C5A. We had to measure level to arc-seconds of accuracy. >> >> >> >> >It's a transformer with a resonant tank in the collector and a >> >> >> >positive feedback drive winding into the emitter. The emitter feedback >> >> >> >is just a couple of tenths of a volt p-p. >> >> >> >> [snip] >> >> >> >> "designed"?? >> >> >> >> Quite _exactly_ like you'd find in common AM radios as the LO, once >> >> >> transistors came upon the scene.... >> >> >> >>http://www.electronics-tutorials.com/receivers/rec-basic-fig1.gif >> >> >> >Cute, and familiar, yes, but that one doesn't have John's c-b >> >> >conduction agc mechanism. �That's a pretty neat feature--have you seen >> >> >it elsewhere? >> >> >> He has a pretty inexact definition of "_exactly_" >> >> >> It seems to mean "not very similar at all." >> >> >Easy boys. �I've designed stuff myself only to find others had beat me >> >to it, and I conversely invented a really neat frequency multiplier >> >which Wenzel and a few others later came up with too. �Mine was in >> >mass production years before, but as far as they know they invented >> >it. >> >> I never claimed that nobody had done this before; how could I know >> that? I do claim that I hadn't seen it done before, nor since. And >> it's cute. Who invented it isn't important; cute is. >> >> The old radio thing that JT linked to is nothing like it. It uses a >> lot more parts and has classic 3-resistor class A biasing, among other >> differences. > >Yeah yeah, we all get that. The circuits speak for themselves. No >need to poke a stick at Jim--he's a good 'ol grizzly bar, just >grouchy. The whole country's grouchy, the people ill-at ease. Such >are the times. Not me. I recently read two articles about getting older: 1. Unless you have dementia, brainpower tends to increase with age. Exercizing your brain, like designing electronics, keeps it healthy. 2. Personal happiness increases up to age 18, declines until about 50, then increases pretty much for the rest of life after that. John |