This circuit was found in an 80's Electronic Engineering. The power supply must be symmetrical. The no value components are calculated for the desired frequency.
This powerful amplifier was part of commercial sound circuits from the 90s. The integrated circuit...
This circuit generates a control tone that serves to adjust amplifiers, check audio cables. The...
This circuit locks when the sensors are opened. The relay can be 6 or 12 V depending on the power...