This circuit can be used as an amplifier for musical instruments or even with your cell phone. The circuit is old and was found in the 1990 edition of Radio Electronics Experimenter magazine.
This TTL circuit uses LED indicators and must be powered by a voltage of 5 V. The capacitor...
Low power RF transistors such as the BF494 or BF495 and even those in the BC series can oscillate well...
This switched power supply was found in a 70s documentation. The basic components are from that...