This very low frequency amplifier has a gain of 1,000 and was found in a 1967 documentation. The circuit is suitable for detecting explosions, distant echoes and seismic vibrations.
Found in a 1980s documentation, this amplifier uses an integrated circuit of the era. The RLC...
This interesting experimental and didactic configuration was found in a 1977 Radio Shack...
This circuit for a frequency of 40 kHz was found in an old Electronic Design. There were no...