This simple Morse Code oscillator was found in a 1980s American documentation. The power supply should be powered with 5V and the integrated can be the 7400.
This anti-ringing circuit was found in an English documentation from 1996. The integrated circuit is...
The figure shows how to increase the gain of the amplifier stage of the previous circuit. The...
This circuit uses unusual operational amplifiers, but equivalents can be tried. FETs can also be...