This circuit was found in a Popular Electronics documentation from the 90s. It is possible to switch the frequency of an oscillator by voltage. The circuit can act as a shield.
This useful power supply was found in an 1985 Italian publication, but can still be assembled...
This dimmer for 12 V incandescent lamps was found in a 1966 General Electric documentation. The circuit has...
With this circuit any number of 4017 integrated circuits can be connected in series. The circuit is...