This circuit was found in the July 1990 Radio Electronics magazine. It is based on the 3-digit indicator ICs CA3161 and CA3162.
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...