Twin T circuit wanted
in [Design]
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From: John Larkin on 6 Jun 2010 23:24 On Sun, 6 Jun 2010 18:05:57 +0100, "john jardine" <zen177928(a)zen.co.uk> wrote: > >"default" <default(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 10/06/04 www.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. John
From: Phil Hobbs on 7 Jun 2010 00:41 John Larkin wrote: > On Sun, 6 Jun 2010 18:05:57 +0100, "john jardine" > <zen177928(a)zen.co.uk> wrote: > >> "default" <default(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 10/06/04 www.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. Order 10 pairs from Zenni Optical and leave them everywhere. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
From: tm on 7 Jun 2010 00:51 "John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message news:35po06tdq5g8shn21k3n9pto73i5vm3vjf(a)4ax.com... > On Sun, 6 Jun 2010 18:05:57 +0100, "john jardine" > <zen177928(a)zen.co.uk> wrote: > >> >>"default" <default(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 10/06/04 www.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. > > John > > In a like request, how about a GQ alarm? I restored a GQ generator on a WW2 sub that used a geared motor to trigger a damped oscillator with mechanical contacts. Of course it was all tubes. T
From: Jan Panteltje on 7 Jun 2010 06:27 On a sunny day (Sun, 06 Jun 2010 20:24:00 -0700) it happened John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in <35po06tdq5g8shn21k3n9pto73i5vm3vjf(a)4ax.com>: >On Sun, 6 Jun 2010 18:05:57 +0100, "john jardine" ><zen177928(a)zen.co.uk> wrote: > >> >>"default" <default(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 10/06/04 www.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. > >John Record a real bell? hehe Those little modules tha trecord a few seconds are cheap. The sound of those bells may even be available on some sound effect sites for free.
From: John Fields on 7 Jun 2010 07:47
On Sun, 06 Jun 2010 20:24:00 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Sun, 6 Jun 2010 18:05:57 +0100, "john jardine" ><zen177928(a)zen.co.uk> wrote: > >> >>"default" <default(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 10/06/04 www.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 |