This circuit found in a 90s Popular Electronics, triggers a huge array of LEDs from the sounds captured by a microphone, thus generating visual effects.
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...