The movement of the LEDs in this circuit mimics the back-and-forth movement of a pendulum, making it suitable for clock projects. The circuit is from a Radio Electronics magazine from May 1978.
This code switch only activates a relay when the right sequence of buttons is pressed. The circuit...
This current-limited variable power supply was found in 1977 book. The diodes are according to...
This circuit for measuring bridges was found in American documentation from the 60's. Transistors are...