We found this circuit in the March 1999 issue of Electronics Now magazine. The indicator used is an analog type. The values indicated depend on the calibration.
The integrated circuit used is a version close to the 555 manufactured by Motorola. The circuit shown...
The circuit shown is from an American publication from 1970. It produces a tone that attracts fish...
Suggested by General Electric documentation from 1968, this circuit activates a relay after 60...