Using the CMOS IC 4046 we found this VCO in the November 1984 Radio Electronics magazine. The center frequency is given by the capacitor. The maximum frequency is around a few megahertz.
This circuit is from a 1991 publication, but it can be assembled with more modern components. We...
This circuit provides a current given by the components calculated according to the formula next...
Published in Radio Electronics in October 1963, this circuit increases the audio output of a small...