This circuit was found in Siliconix documentation from the 1980s. Equivalent operational amplifiers can be used and the output current is very low.
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...