Found in a 1966 Electronics World, this circuit applies to the protection of any analog instrument. The diodes can be of any general-purpose type.
This configuration was found in the January 1992 Radio Electronics magazine. The frequency is set...
The microwave sensor of this circuit is a common ceramic capacitor. The circuit is from an 80's...
This sensor circuit for a small robot was found in a Popular Electronics from the 90s. The circuit...