Based on the 4017 integrated circuit, this circuit of a European 303 Circuits from the 90s, generates a pulse train in a relay that mimics the dialing of a telephone.
Found in Popular Electronics this circuit will trigger a buzzer if the ignition key is removed...
Found in Popular Electronics, this sophisticated short-wave receiver requires a lot of skill from...
This circuit is from an old American documentation using LEDs in the rectification. The circuit...