This high input impedance tone control circuit was found in American documentation from the 1980s. Equivalent operational amplifiers and FTEs can be used.
With this circuit, a relay can be activated from an alternating signal with frequency up to a few...
With this circuit the visually impaired can easily locate important places inside the house, such...
In the figure we have the way to use the transistors of an old-paired pair as a trigger circuit. The...