This two-tone decoder has a bandwidth of 24%. The circuit is from a 1994 Electronics Now. The components without the value determine the recognized frequency.
This circuit uses the Linear Technology LT6505 and was found in a 2005 manual. The circuit is for 24 V...
This circuit uses components from the time it was published. The circuit is from the 80's. The...
This sophisticated logic probe for 5 to 12 V circuits (CMOS and TTL) was found in a 1980s...