This circuit simulates a resistor controlled by digital signals. We found it in American documentation from the 90s. The basic component is a CMOS 4016 or 4066 digital switch.
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...