Tonewheel
A tonewheel or tone wheel is a simple electromechanical apparatus for generating electronic musical notes in electromechanical organ instruments such as the Hammond B-3. It was invented around 1910 by Rudolph Goldschmidt and was first used in pre vacuum tube radio receivers as a beat frequency oscillator (BFO) to make continuous wave radiotelegraphy (Morse code) signals audible.
Description
The tonewheel assembly consists of a synchronous AC motor and an associated gearbox that drives a series of rotating disks. Each disk has a given number of smooth bumps at the rim; these generate a specific frequency as the disk rotates close to a pickup assembly that consists of a magnet and electromagnetic coil.
As each bump in the wheel approaches the pickup, it temporarily concentrates the magnetic field near it, and thus strengthens the magnetic field that passes through the coil, inducing a current in the coil by the process of Electromagnetic induction. As the bump moves past, this concentrating effect is reduced again, the magnetic field weakens slightly, and an opposite current is induced in the coil. Thus, the frequency of the current in the coil depends on the speed of rotation of the disk and the number of bumps.
Podcasts:
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by Danni Leigh
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by Danni Leigh
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by Danni Leigh
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by Danni Leigh
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by Danni Leigh
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by Danni Leigh
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by Danni Leigh
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by Denali
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Mixed Up Mess of a Heart
by: Danni LeighOh, you poor, broke, mixed up mess of a heart
You let a little bitty man go and tear you all apart
I warned you a thousand times
You wouldn't listen, paid me no mind
You poor, broke, mixed up mess of a heart
I watched him buy his ticket in Charlotte, North Carolina
I heard him say, "One way, please to Denver"
He's goin' to meet that other girl
Won't do us no good to cry
'Cause she's wearin' his ring on her finger
Oh, you poor, broke, mixed up mess of a heart
You let a little bitty man go and tear you all apart
I warned you a thousand times
You wouldn't listen, paid me no mind
You poor, broke, mixed up mess of a heart
I watched him tip the porter
As he stepped aboard that midnight train
Bound to take him far away forever
I watched the tail light fade away
Knowin' he was gone to stay
I just wish this broken heart was with him
Oh, you poor, broke, mixed up mess of a heart
You let a little bitty man go and tear you all apart
I warned you a thousand times
You wouldn't listen, paid me no mind
You poor, broke, mixed up mess of a heart
Oh, you poor, broke, mixed up mess of a heart
You let a little bitty man go and tear you all apart
I warned you a thousand times
You wouldn't listen, paid me no mind
You poor, broke, mixed up mess of a heart