Using the LM170 integrated circuit, this circuit was found in the May 1970 Radio Electronics magazine. The transistor is general-purpose, and the potentiometer adjusts the gain.
We found this circuit in the Linear Applications Handbook of the National Semiconductor of 1994....
This circuit was obtained from a 90sLinear Technology documentation. It is a current source that...
This is a possible circuit for the receiver of the previous circuit. Other circuits can be found...