This bargraph circuit is from an ancient American documentation. It indicates the charge state of a set of 4 batteries from 9.6 to 5.2 V.
This circuit makes the RIAA equalization for signals obtained from a turntable for signal recovery in other...
This circuit also detects IR, providing LED indication. The circuit is used to indicate humidity in...
The circuit shown is a suggestion by National Semiconductor in its 1994 Linear Applications...