This timer was found in English documentation from the 80's. The integrated circuit is common nowadays and the MOSFET admits equivalent according to the controlled load.
Found in Radio Electronics from the 90s, this circuit can vary the frequency in small values...
This circuit was found in the August 1994 issue of Electronics Now magazine. The 4046 is uncommon...
This circuit is based on an operational amplifier that is no longer common today but can be...