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.
This circuit was obtained in a documentation for radio amateurs from 1975. With it we can use a...
Only for reference this is a circuito f a commercial receiver of the year 1958. The circuit uses...
This circuit is from an old American publication. The indicated transistor is oversized as the 15 V...