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 10 kHz filter was obtained from an article in Electronics Now magazine in February 1995. The...
Other series amplifiers such as the MC3301, MC3401 and LM2900 can be used on this circuit. We found...
This circuit was obtained from an American publication of the 80's. The integrated circuit is of the...