This 80's circuit can be implemented with modern equivalent FETs with lower on resistance. The attenuation is 80 dB at 100MHz.
Found in a 1980s American documentation, this circuit has a current consumption of only 1 mA. The...
This audio millivoltmeter was found in a 1992 publication. It can still be assembled, as the...
This very simple continuity tester uses a small 1.5 V lamp (type used in flashlights). Can be...