This circuit is intended for underwater communications. Of course, the critical point is the shielding to avoid water. The circuit is from an Electronic Hobbysts Handbook from the 90s.
This simple trigger circuit was found in a 90’s American documentation. The integrated circuit is...
This sensitive circuit was found in the August 1971 issue of Radio Electronics magazine. The SCR...
The varactor or varicap diode tunes the signal for listening to SSB signals on a common receiver. The...