This circuit was found in 1980's Radio Electronics. The circuit produces a 1500 Hz modulate 35 kHz. The components used are still common.
This circuit was obtained from a 1965 magazine, but can still be assembled if we use a modern 6 V...
This circuit is nothing more than a turn signal for two alternating LEDs that can decorate a robot...
This circuit was found in a 90s Popular Electronics. It produces a muted tone similar to that...