We found this circuit in a 1982 documentation. It uses a CA3140 or equivalent operational amplifier and does not require a symmetrical source. The output is 1 Vpp wide.
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...