This circuit also detects IR, providing LED indication. The circuit is used to indicate humidity in bench tests. We found it in the Radio Electronics magazine of February 1990.
We found this circuit in an 80's Electronic Design. It makes use of couplers of the time that can...
Found in a 1965 Electronic Design the purpose of this circuit is to control the gain of a stage by...
Employing the XR2206 IC, this circuit was found in the May 1977 issue of Radio Electronics...