The circuit shown in the figure below is from the 1993 Linear Technology Applications. The operational ones used are uncommon and the use of equivalents can be analyzed.
This circuit is from the Radio Electronics magazine of May 1984. With it, it is possible to...
A VCO or voltage-controlled oscillator, which uses only two of the LM3900 amplifiers, is shown in the...
This is one of the many versions of amplifiers with LM386. This was achieved in an old publication (1981). The...