This circuit was found in a 90s Popular Electronics. The sensors can be common speakers that reach from 15k to 25 kHz, such as piezoelectric tweeters.
The figure shows how to use the LM3914 bargraph with expanded scale. The circuit has two...
November 2016 - Mouser Electronics is indicating in its inventories the new NXP Kinetis L MCUs....
This circuit was found on a Radio Elettronica (Italy) from April 1974. The circuit can be easily...