This circuit, with printed circuit board, is from an article in Radio Electronics magazine from May 1971. The circuit uses the C106 which was already a common component at the time.
This circuit was obtained from an old American documentation having a limited adjustment range....
The movement of the LEDs in this circuit mimics the back-and-forth movement of a pendulum, making it...
This circuit is from a 1967 documentation. It makes use of varicap and diode tunnel in addition to...