This circuit was obtained in an old Popular Electronics. It makes use of quite common components. The speed of the effect is set to R7. The circuit drives 20 LEDs.
This circuit is from 1995 documentation. The power depends on the transformer, which in this case...
Found in a 90s Electronic Design, this circuit generates harmonics from a sinusoidal input signal....
This simple circuit needs a high gain stage to compensate for losses. It consists of a passive tone...