Using a capacitor as a sensor, this circuit was found in the 1989 Radio Electronics Experimenter magazine. The circuit must be assembled in a shielded box.
This circuit was published in a 1979 magazine, but it can still be easily assembled as the...
The integrated circuit of this amplifier is not very common today. The output transistors can be...
Found in an old documentation about neon lamps, this circuit has the frequency basically...