Suggested by a 90s Popular Electronics this circuit is intended to receive volleys or whistles from thunderstorms in the wave range below 20 kHz. The coil consists of 300 turns of wire 26 in a ferrite rod.
This circuit, from a publication from the 1970s, can be implemented with more modern transistors and 6 or...
This circuit switches off a load in case of excess current acting as a fuse. The circuit is from a...
This circuit was obtained from a manual of the integrated circuit itself, but can be applied to...