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.
This circuit keeps the neon lamp on for a moment when it receives a pulse. The turn on time...
This circuit was found in General Electric's 1965 documentation. It appears elsewhere on the site....
This configuration was found in a 1990s documentation. Modern operational amplifiers can be used...