Page "Diode" Paragraph 7

Diodes were the first semiconductor electronic devices.

The discovery of crystals ' rectifying abilities was made by German physicist Ferdinand Braun in 1874.

The first semiconductor diodes, called cat's whisker diodes, developed around 1906, were made of mineral crystals such as galena.

Today most diodes are made of silicon, but other semiconductors such as germanium are sometimes used.