This circuit was found in Raytheon's 1967 documentation. The circuit uses an operating of the era, but the configuration can be applied to modern operational amplifiers.
This circuit is from an 80's documentation, applying to ordinary comparators. The source does not...
This circuit produces an intermittent ring tone being triggered directly by the telephone line. However,...
This loop antenna was found in a 1990s documentation. The circuit includes a field strength meter. The...