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, from the 90's, is intended for operation with vinyl record players of the time, as...
Using a zener diode it is possible to change the linearity of the scale of an analog instrument by...
Found in American documentation from the 1980s, this circuit prolongs the ringing of a doorbell or chime...