Heinrich Hertz ( 1887 ) experimentally demonstrated the resonance phenomena by building two resonant circuits , one of which was driven by a generator .
The other was tunable and only coupled to the first electromagnetically ( i.e. , no circuit connection ) .
Heinrich Hertz ( 1887 ) experimentally demonstrated the resonance phenomena by building two resonant circuits , one of which was driven by a generator and the other was tunable and only coupled to the first electromagnetically ( i.e. , no circuit connection ) .