This circuit from the 80's makes use of two transconductance operationals of the time. Modern equivalents can be used. The circuit does not need to be powered by a symmetrical source.
Two LEDs are used in this TTL circuit. Frequency is given by C1 and C2. Power supply must be a 5 V...
The oscillator shown in the figure generates a rectangular signal with a 50% active cycle (square)...
This circuit was obtained from a Radio Electronics from October 1963. The 4 transistors must be...