Suggested by Siliconix in documentation from the 90s, this circuit can present gains of digitally selected by the input going from 1 to 1000. The circuit can be adapted to work as a shield.
Found in old documentation about neon lamps, this circuit shows how to add a simple blown fuse...
This circuit was found in a 1980s documentation. It triggers a relay when liquid from a reservoir...
For counting to values higher than 16, many 4520 can be cascaded as shown in Figure . The EN...