This circuit switches power loads with audio signals. The circuit is from a Popular Electronics from the 90s. The components can be changed depending on the signal used.
This conventional series reducer circuit reduces the voltage of a 12 V battery to the selected value...
In the figure we have a converter that generates a negative voltage from a positive voltage...
This circuit covers the bands from 1.8 to 150 MHz, with plug-in coils whose characteristics are...