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.
This simple window comparator based on the well-known LM339 was found in the June 1998 issue of...
This circuit makes use of a transconductance operational amplifier. It generates signals with TTL...
This circuit has a traditional configuration often found on this site. The transistor must be...