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 portable transceiver circuit for the 11 meter or 27 MHz band was found in a 1991...
This circuit was found in an American 1980s documentation. It makes use of an unusual MOSFET today...
This circuit was found in an old Linear Technology documentation. The working principle can be...