High pressure: such as the metal halide, high pressure sodium and mercury vapor lamps ... frequencies of around 20 kHz. The neon lamp in the circuit does not conduct until the voltage of the ...

It was as though someone said “Fiat lux sulfurea—“Let there be light ... of sodium streetlights is documented in NASA night photographs from space: New York City and Los Angeles are circuit ...

Whenever the circuit was closed both D lines were seen ... It thus appears very probable that the period of sodium light is altered in the magnetic field. It is remarkable that Faraday, as early ...