This circuit is for old telephones with analog lines. It was found in the May 1988 Radio Electronics magazine. The circuit is powered by the line signal voltaje.
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...