This circuit uses a Motorola component from the 90's and is suitable for the diode-transistor logic of the time. The circuit can be adapted to use more modern equivalent logic.
To use the instrument for AC measurement, the tips are A and B. For CC use tips A or B for...
The interesting circuit shown in the figure, can have its gain digitally controlled and present two...
This simple MW radio was found in a 1975 publication, but it can be mounted with BC548...