This be Mini Trombone Sound generator circuit. By using integrated circuit the number LM3909 of NS. In using loudspeaker 25 Ohm sizes work by use voltage from AA 1.5V battery. In sound occurrence that resemble with trombone.
It have the work depends on the principle uses voltage, which the generator by the occurrence Resonance of sound coil of a loudspeaker is feeding gets back to the way adds to give with integrated that circuit was set up in large-sized box,which there is the capacity about 64 inch cubic which one side of a box has can to move in and out resemble a cylinder a position of a piston.
The work of switch press will cause the tone of voice that resemble very integrated loudspeaker circuit and battery touch set up on a piston , which there are 5 size inch pipes. For be born air push reaches and go out while a piston moves by don’t affect to build the frequency Resonance. The frequency of origin frequency circuit will begin to equal to the frequency Resonance of a box.
source: elecfree.com
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