This simple circuit has good gain and can be implemented with any general-purpose transistor. The circuit is from Electronics Now, June 1997. The coil determines the frequency range.
This stage for JFETs was found in a 1965 US publication, but is valid for modern components. |...
This traditional configuration of bandpass or bandpass filter with operational 741 was found in a...
With 3 flip-flops (which correspond to 1 integrated and a half) we can also make a divider by 8,...