The four-layer diode, also known as a Shockley Diode, is a crystal made of alternating layers of N- and P- type semiconductors. By putting in four layers, instead of the three used in transistors ...

A crystal radio is basically a high Q resonator tied to an antenna and an envelope detector. These days the envelope detector is a point contact diode such as a 1N34 Germanium diode. The resonant ...

Perhaps the simplest radio one can build is the crystal radio. Using a diode as a detector, the design generally uses less than 10 components and no battery, getting its power to run from the ...