This unijunction transistor circuit is a frequency divider synchronized to 100 kHz. The circuit was found in a Radio Electronics from July 1968. The adjustment of R4 is important.
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...