This circuit uses a resonant reed relay to recognize the frequency of an input signal. Adaptations can be made to obtain functioning as a shield. The circuit is from 1965 documentation.
This circuit generates voltages of tens of thousands of volts for projects such as electrostatic filters...
This circuit was found in an old American documentation. The operational used is of the...
Rechargeable Nicad batteries type AA, C or D can be recharged with this circuit, which is nothing...