The sound of drums can be obtained with these two touch-triggered double-T oscillators. The circuit is from a Radio Electronics Special projects from 1993.
Using a 4046 PLL this circuit recognizes a 1.6 to 1.8 kHz tone by driving an output LED. The...
This battery charger circuit was found in ancient American documentation. The components are...
This circuit is of great use today, when solar energy is becoming increasingly important. The...