This circuit from the 90s, found in an Electronic Engineering can be used as a shield since its control is digital with TTL logic of 5 V. The components used are still common today.
This normally open, two-terminal, high-sensitivity circuit was found in General Electric's...
Bubba's oscillator, shown in the figure, is another type of phase shift oscillator, but it takes...
This sensitive electroscope uses a MOSFET 3N128 and can detect electrostatic charges of objects....