This circuit triggers in 100 microseconds in case of excess voltage. The adjustment is made in the pot. The circuit was found in 1969 documentation.
This traditional doubler configuration with the 555 IC can be found in other articles on the...
This circuit is from an 80's component manual. The components are from the time, but the circuit...
This circuit for the 3.5 MHz band (80 meters) was found in an old radio amateur documentation. The circuit...