We found this circuit with duty cycle adjustment in the May 1988 Radio Electronics magazine. The source must be symmetrical, and the frequency given by R3 and C1.
This circuit was originally designed for the practice of Morse code, something common in 1966, the year...
This is a circuit that appears several times in this section and in articles. It is a preamplifier for...
Using the 723 integrated circuit, this circuit was obtained from an article in the August 1971...