This is an example of the first useful kind of radio detector (invented in the late 1800s) - a "coherer". It consists of a pair of electrodes separated by a loose pile of iron filings. When activated by a strong radio signal (in this case generated by a spark gap transmitter) the resistance of the coherer changes from high to low. This state persists until the device is physically shaken.
@The1JTA Fe is iron
coilsinamotor 1 year ago
Since names are being mentioned - I've seen this cited to Edouard Branly - 1890
Have you tried Ni and Fe?
The1JTA 2 years ago
it was invented by the italian physicist Temistocle Calzecchi Onesti and used by Guglielmo Marconi
Eumolpo89 2 years ago
I'm sure doctor Lodge would be proud.
Probewitch 3 years ago
cool!
SCIFIaction 3 years ago