Found in a 1969 documentation, this neon lamp circuit may have the number of steps increased. The power supply is made with high voltage.
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...