This circuit has a 100 dB dynamic We found it in a Popular Electronics from the 90s. Equivalent operational can be used.
This circuit is based on a regulator component that consists of a transistor and zener in the same...
We found this conventional circuit with the 555 in a documentation from the 70s. Several similar or...
This amplifier with gain control was obtained in a documentation from Signetics of the 80's....