This circuit that draws 1 out of 8 LEDs was found in an 80's American documentation. The circuit can also work with an astable using the 555 instead of the 4046 which is not a common component today.
This oscillator for various frequencies was obtained from a 1980s telecom documentation. The...
This audio stage can be used in siren circuits, sound effects and others to excite a few watts...
This circuit was found in the August 1992 issue of Radio Electronics magazine. The circuit can be...