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 is from a 1968 documentation using one of the first integrated circuits available at the...
This circuit was found in a 1965 General Electric documentation. SCRs and unijunction may be...
This precision circuit can be implemented with other operational ones. We found it in a...