This crowbar circuit for alternating current causes a quick fuse to blow when the load current exceeds a certain value. The circuit is from an American 80's documentation.
This circuit was found in a NASA documentation from the 1980s. The components used are of the time...
This is a traditional version of electroscope with FET. We found it at Popular Electronics. The...
This circuit tests the grounding of a three-pin outlet. We found it in a Popular Electronics from the 80s....