This nice analog indicator circuit was found in the January 1974 issue of Radio Electronics magazine. The circuit has 8 scales with individual adjustments. The instrument is rated at 50 uA.
The circuit shown is from an old European publication. In it we have the way to activate a relay...
We found this circuit in a European publication from the 1990s. Transistors are still common types...
This circuit was found in an American documentation and can be added to common amplifiers of any...