This circuit has a sensitivity of 2uW. We found it in documentation from the 1980s. The integrated circuit is from that time. Equivalents can be tried.
We found this circuit in a 1976 documentation, but it can still be easily assembled using BC548...
This circuit of an old publication produces the insect-like noise that drives them away. The...
This circuit aims to increase the selectivity of receivers whose FI is 455 kHz. The circuit is...