This circuit was found in a Modern Transistor Workbook from 1965. The circuit sends signals from a small record player to a medium-wave radio placed nearby.
In figures 1 and 2 we have two current drains that can be made with operational amplifiers and...
Great sensitivity for the circuit can be obtained with a Darlington amplification step for the...
The used diode is an unusual component today. We found this 12 V regulator in documentation from the...