In electronics, a diode is a two-terminal electronic component that conducts primarily in one direction; it has low resistance to the flow of current in one direction, and high resistance in the other. A semiconductor diode, the most common type today, is a crystalline piece of semiconductor material with a p–n junction connected to two electrical terminals. A vacuum tube diode has two electrodes, a plate and a heated cathode. Semiconductor 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 selenium or germanium are sometimes used.
This diode is able to detect RF signals and converts it to DC electricity to power a Led the amazing thing about this is that its completely passive and doesn't require any batteries... Gold Plated Slug 1N23B is Vintage U.S. ARMY Military for General Purpose UHF-MW Silicon Mixer. Primarily used in the Allies’ radar systems during World War II.