This circuit for the very low frequency range was found in the Radio Electronics magazine of February 1983. The components are according to the frequency range to be amplified.
This circuit is from a 1998 Electronics Now and can be easily assembled since it uses a common...
We find this circuit in an American 80's documentation. No further information about the...
With this circuit, an external circuit can be controlled by turning it on or off and reversing it (if...