Found in a magazine 73 for radio amateurs of the 90s, this circuit converts a continuous voltage and another continuous voltage, but with insulation between the circuits.
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...