Operating at just 1.35 V this circuit was found in a 1969 Electronic Design. The circuit makes use of transistors of the time but can be implemented with current equivalents.
This preamplifier for record players with crystal capsules was found in Radio Electronics magazine...
Modern operations can be used in this circuit that multiplies a capacitance of 10,000 uF for a...
This interesting circuit, found in a 1997 documentation, allows you to view the characteristic curves of...