This third-order Butterworth filter was found in American documentation from the 1980s. Formulas for component calculations are attached to the diagram.
Found in a 1965 Radio Shack documentation this oscillator can be used with modern general purpose...
In the figure we have a voltage / frequency converter circuit that can be used as a transducer interface...
This small stereo amplifier for headphones was found in a documentation on integrated circuits from...