Twin T circuit wanted
in [Basics]
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From: dagmargoodboat on 7 Jun 2010 20:06 On Jun 7, 12:29 pm, Jim Thompson <To-Email-Use-The-Envelope-I...(a)On-My- Web-Site.com> wrote: > On Mon, 07 Jun 2010 11:50:25 -0500, John Fields > > > > <jfie...(a)austininstruments.com> wrote: > >On Mon, 07 Jun 2010 06:47:45 -0700, John Larkin > ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > > >>On Mon, 07 Jun 2010 06:47:07 -0500, John Fields > >><jfie...(a)austininstruments.com> wrote: > > >>>On Sun, 06 Jun 2010 20:24:00 -0700, John Larkin > >>><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > > >>>>On Sun, 6 Jun 2010 18:05:57 +0100, "john jardine" > >>>><zen177...(a)zen.co.uk> wrote: > > >>>>>"default" <defa...(a)defaulter.net> wrote in message > >>>>>news:9dhk06dltvk703cdpri3dt91bvjnbjr6cf(a)4ax.com... > >>>>>> Can someone supply a single transistor circuit that will give a damped > >>>>>> sine wave when a pulse is applied? to emulate a bell sound > >>>>>> -- > > >>>>> ,---------, > >>>>> | |5V > >>>>> .-. - > >>>>> | | --- > >>>>> | |4k7 | > >>>>> '-' === > >>>>> | GND > >>>>> ,-----------------------------o-----o > >>>>> | | | Damped Sine > >>>>> | .-.1M o-------o Out > >>>>> | | | | -> ~1Vpp > >>>>> | | | | > >>>>> | 10k 10k '-' | > >>>>> | ___ ___ || | |/ > >>>>> o---|___|---o--|___|--o--||---o---| BC547 > >>>>> | | | || |> > >>>>> | --- | 10u | > >>>>> | ---100n | o------ > >>>>> | | | | | > >>>>> | === | | --- > >>>>> | || || | | --- 10u > >>>>> '----||-----o----||---' | | > >>>>> || | || .-. | > >>>>> 10n .-. 10n | | .-."Q"Pot > >>>>> | | | | | |<-. > >>>>> | | '-' | | |220 > >>>>> '-'1k 1k | '-' | > >>>>> -> | | | | > >>>>> PIC o------------' === === === > >>>>> Narrow Pulse GND GND GND > >>>>> to Ring > > >>>>>(created by AACircuit v1.28 beta 10/06/04www.tech-chat.de) > > >>>>Here's my ship's fog bell generator, as I remember it. The decay was > >>>>set by tapering off the supply voltage to 4 or maybe 5 LC oscillators, > >>>>so Q didn't matter. It sounded pretty good. > > >>>>ftp://jjlarkin.lmi.net/Ships_Bell.JPG > > >>>>A refinement would be to have a separate decay rate for each > >>>>oscillator, since some harmonics of a real bell fade at different > >>>>rates from others. > > >>>>Yikes, I remember thousands of schematics but can never recall where I > >>>>left my glasses. > > >>>--- > >>>Apparently, since what he asked for was a: "single transistor > >>>circuit". ;) > > >>>JF > > >>This is a discussion group, > > >--- > >Excellent! > > >I see that your usual remarkable grasp of the obvious is still flying > >unfettered. > >--- > > >>and the subject was circuits that simulate > >>bells. > > >--- > >Sorry, but no. > > >The subject was: "Twin T circuit wanted", while the body of the > >message read: "Can someone supply a single transistor circuit that > >will give a damped sine wave when a pulse is applied? to emulate a > >bell sound". > > >You posted neither a twin tee circuit nor a single transistor circuit, > >but rather something so that you could pat yourself on the back > >regardless of the OP's request. > >--- > > >>You posted none. Why is that? > > >--- > >I chose not to, but to criticise you instead. > >--- > > >>A single-oscillator version of my thing doesn't sound as good, but it > >>is sort of bell-like. > > >--- > >OK, but then there's still the question of the two-transistor > >capacitor charger-upper and whether or not it's part of the circuit, > >but I'm sure you'll get around that somehow. > > >Then, of course, the poor OP's got to figure out the transformers and > >the values of all the components, but that's OK since you're just > >throwing out ideas, not designs, eh? > >--- > > >>It's a cinch you're not going to simulate 5 > >>damped oscillation modes with one trensistor. [1] > > >>Show us your single-transistor bell simulator circuit. > > >--- > >All in due course, if I choose to, but it seems that John Jardine has > >already done a nice job of it, so why should I accept your invitation > >to a sissing contest? > >--- > > >>John > > >>[1] the original touch-tone telephone managed to make > >>controlled-amplitude DTMF tone pairs from a single transistor, sort of > >>defying conventional wisdom about oscillator modes. > > >--- > >All well and good, but what does that have to do with generating > >bell-like tones? > > Larkin believes he can dig himself out of a hole with a shovel :-) I don't get all the sniping. John posted a circuit--it was cute. Single-transistor (if that mattered) for a single resonant mode, plus extra optional modes if you want to simulate a real bell's complexities. Not exactly what the OP asked for, but that's how he (the OP) discovers choices and alternatives. He may not've known about the extra modes' importance to realistic bell sounds. If the OP's dead set on a twin-tee, he'll say so. There are bigger, more important things going on in the country than picking on John. -- Cheers, James Arthur
From: Jim Thompson on 8 Jun 2010 11:31 On Mon, 07 Jun 2010 20:33:23 -0700, John Larkin <jjlarkin(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 First one I hit upon surfing. I'll look for _my_ first radio that used CK760's :-) ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | The only thing bipartisan in this country is hypocrisy
From: dagmargoodboat on 8 Jun 2010 13:00 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 > > First one I hit upon surfing. I'll look for _my_ first radio that > used CK760's :-) 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? -- Cheers, James Arthur
From: John Larkin on 8 Jun 2010 15:09 On Tue, 8 Jun 2010 10:00:55 -0700 (PDT), dagmargoodboat(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." John
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. -- |