This circuit with a bargraph scale was found in a 90s Popular Electronics. The circuit measures the intensity of a sound in three scales. R14 works as a sensitivity adjustment.
This sensor circuit was found in an American 1980s documentation. Modern operational amplifiers can...
August 2017 - Mouser Electronics already has to supply the new Darlington MAAM-011206 Broadband...
This circuit was suggested by General Electric in a 1965 documentation. The circuit can be...