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Re: Twin T circuit wanted

>> 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
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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

Reply to
John Larkin
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Order 10 pairs from Zenni Optical and leave them everywhere.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal
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Reply to
Phil Hobbs

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
Reply to
tm

On a sunny day (Sun, 06 Jun 2010 20:24:00 -0700) it happened John Larkin wrote in :

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.

Reply to
Jan Panteltje 

--
Apparently, since what he asked for was a: "single transistor
circuit". ;)
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Reply to
John Fields

This is a discussion group, and the subject was circuits that simulate bells. You posted none. Why is that?

A single-oscillator version of my thing doesn't sound as good, but it is sort of bell-like. 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.

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.
Reply to
John Larkin

The fog bell circuit I did replaced a Henschel unit that actually whacked a metal bar with a solenoid and picked up the result with a magnetic pickup coil. It sounded pretty ratty.

John

Reply to
John Larkin

Years and years ago I did an analog "Warning Chime/CPU Monitor for Automotive Applications", which provided CPU POR functions and chime/alarm sounds in GM products. The chime sound was cleaner than the original bar "clacker". ...Jim Thompson

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| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
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Reply to
Jim Thompson

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

This is the one I repaired many years ago. Others now keep it working.

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I'd like to have it as a ring tone somehow.

Tom

Reply to
tm 

--
Excellent!

I see that your usual remarkable grasp of the obvious is still flying
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Reply to
John Fields

Larkin believes he can dig himself out of a hole with a shovel :-) ...Jim Thompson

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| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
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Reply to
Jim Thompson

You'd fit better in a whining group. I think some exist.

Sure, use your best skills: if you can't do electronics, and never have ideas, bitch about people who can and do. JT and Sloman will assist.

Best to avoid actual circuits and numbers, since you're usually wrong.

John

Reply to
John Larkin 

--
I fail to see where attacking you constitutes whining, so perhaps what
you really meant was that you'd like me to stop because you can't come
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Reply to
John Fields

Looks to me like you're trying to out-Slowman Slowman... but you're not even competent at that :-) ...Jim Thompson

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| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
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Reply to
Jim Thompson

Defense against what? You rarely talk electronics, and then you're usually wrong. If you want to get picky about dictionary definitions and such, go for it.

This is an electronics group.

I could have sworn he wanted a circuit to emulate a bell sound.

We'll have to take your word for that, like we do for Sloman's "expertise" and "educated palate."

What do you want, a BOM and dimensioned fab drawings? Send me a PO first.

I drew this from memory, and I don't remember the values. I designed it about 35 years ago. It worked. We sold a bunch of them.

The point of this circuit is that

A. Multiple decaying sines sound more bell-like and

B. A separate RC can control the decay envelope, as opposed to a potentially tricky Q adjustment. It takes very little gain change to go from a Q of 500 to 100, or continuous oscillation.

What are your technical opinions on the subject?

In this group, that's pretty much what they do. They tell us how smart they are (or used to be), abuse other people for being dumb, and contribute not much content.

I wonder if they have any good bell circuits.

How about your charge pump stuff?

John

Reply to
John Larkin

[snip]
[snip]

As a matter of fact I have a _really_good_ bell circuit, but I'm waiting for you to firmly bury you shoe in the cow patty before I reveal it ;-)

You really do need to review your "capabilities"... you're not even very good at emulating a horse's ass :-) ...Jim Thompson

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| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
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Reply to
Jim Thompson

mped

=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0,---------,

=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0| =A0 =A0 =A0 =A0 |5V

=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 .-. =A0 =A0 =A0 =A0-

=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 | | =A0 =A0 =A0 ---

=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 | |4k7 =A0 =A0 |

=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 '-' =A0 =A0 =A0 =3D=3D=3D

=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0| =A0 =A0 =A0 =A0GND

----o

=A0 =A0 =A0 =A0 =A0 =A0 =A0 | =A0 =A0 | =A0 =A0Damped Sine

=A0 =A0 =A0 =A0 =A0 =A0 =A0.-.1M =A0o-------o Out

=A0 =A0 =A0 =A0 =A0 =A0 =A0| | =A0 =A0| =A0 =A0-> =A0 ~1Vpp

=A0 =A0 =A0 =A0 =A0 =A0 =A0| | =A0 =A0|

=A0 =A0 =A0 =A0 =A0'-' =A0 =A0|

=A0 =A0 =A0|| =A0 | =A0 |/

--| BC547

=A0 =A0 | =A0|| =A0 =A0 =A0 |>

=A0 =A0| =A010u =A0 =A0 =A0 =A0|

=A0| =A0 =A0 =A0 =A0 =A0 =A0 o------

=A0 =A0 | =A0 =A0 =A0 =A0 =A0 =A0 | =A0 =A0 |

=A0 =A0 =A0 =A0| =A0 =A0 =A0 =A0 =A0 =A0 | =A0 =A0---

| =A0 | =A0 =A0 =A0 =A0 =A0 =A0 | =A0 =A0--- 10u

=A0 =A0 =A0 =A0 | =A0 =A0 |

=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0.-. =A0 =A0|

=A0 =A0 =A0 =A0 =A0 =A0 =A0| | =A0 .-."Q"Pot

=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 | | =A0 | | >>>>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 | | =A0 =A0= =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 '-' =A0 | | =A0|220

=A0 =A0 =A0 =A0 =A0 =A0 =A0 1k | =A0 =A0'-' =A0|

=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 | =A0 =A0 | =A0 |

=A0 =A0 =A0 =A0 =A0=3D=3D=3D =A0 =3D=3D=3D =3D=3D=3D

=A0 =A0 =A0 =A0 =A0 =A0 =A0GND =A0 GND GND

,
I

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

Reply to
dagmargoodboat

I loved your bell circuit John! I didn't quite get how the inductor was working. But still I got the idea. Thanks.

George H.

Reply to
George Herold

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.

The cool thing is that the collector swing is almost exactly 2xVcc peak-to-peak. As the amplitude builds up, at the negative swing peak the emitter goes a little bit negative, to get out of the way, and the collector swings to just about ground. That forward-biases the c-b junction and discharges the base cap, reducing transistor base current hence gain. So it has a built-in peak detecting AGC amplitude levelling loop with close to zero TC. All from 5 parts. Or sometimes six.

I tested the system on a 55 gallon drum full of sand, with a huge steel plate on top. We built a platform that pivoted on ball bearings and we moved a long lever arm with a micrometer, to tweak the sensor angle. I had to tell people not to walk nearby, because their weight would flex the concrete slab of the building.

I learned a bunch on this project: HeNe laser power supplies, synchronous detectors, optics. I've always sort of liked this oscillator.

John

Reply to
John Larkin

ftp://jjlarkin.lmi.net/Ships_Bell.JPG

With your explanation, the oscillator is much more attractive. Some folks can't stomach magnetics, perhaps that's part of the criticism. Anyway, ignore JF and JT when they get bitchy, it must be something they ate, or is age catching up with 'em?

Our old friend, Tony Williams, R.I.P., would have been pleased.

. John Larkin's LC oscillator, supply-V sets amplitude . _________________ . | | | . | _|_C E || L . Rb --- E || . | | E || . | | * | || . | +-----' || . | | || . | C gnd || . +- B | || . _|_ E E || . --- | * | || . | +-----' || . gnd | . '--- out

Tell us more about the inductor / transformer, turns ratio, etc. Did I get the winding polarities right? I suppose you have to keep the emitter's reverse-voltage under say 5V breakdown, so 10Vpp max output? What are the prospects for making this into a high-power oscillator? Drive a speaker directly?

--
 Thanks,
    - Win
Reply to
Winfield Hill

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