Circuit Project Electronic

This circuit is a octave shifting that is used for electric guitar is done by rectifying the original signal, just like AC to DC conversion inside your AC-DC power supply adapter. This circuit is use single supply instead of symmetric power supply. This is the figure of the circuit.
The rectifying is done by four 1N4148 [...]

A simple sound generator IC that can produce four sound effects. Designed for use in toys, the effects are selected by varying the connections to pins1 and 6 as follows.
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Source: http://www.next.gr/inside-circuits/
Sound-effects-generator-UM3561-l5863.html

This be Basic Tone Generator by UJT Transistor 2N4891 numbers. By it s can give with small-sized loudspeaker s have a voice electric loud bell moderately. The value of C1 be valuable a little for enhance the speed in the package and disgorge to load. In each round (Cycle) [...]