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.
Found in an old neon lamp applications manual, this circuit directly triggers an SCR. R and C...
This 20 MHz bandwidth circuit was suggested by the National Semiconductor in 1970 documentation. Modern...
This circuit cuts out ads between songs, based on the fact that the speech signal has small...