Search results
Results from the WOW.Com Content Network
Galena cat whisker detector used in early crystal radio Precision crystal detector with iron pyrite crystal, used in commercial wireless stations, 1914. The crystal is inside the metal capsule under the vertical needle (right). The leaf springs and thumbscrew allow fine adjustment of the pressure of the needle on the crystal.
A crystal detector includes a crystal, usually a thin wire or metal probe that contacts the crystal, and the stand or enclosure that holds those components in place. The most common crystal used is a small piece of galena ; pyrite was also often used, as it was a more easily adjusted and stable mineral, and quite sufficient for urban signal ...
Until the vacuum tube matured, the crystal detector was the most sensitive and dependable detector available—with considerable variation between mineral types and even individual samples within a particular type of mineral. Pyrite detectors occupied a midway point between galena detectors and the more mechanically complicated perikon mineral ...
While not the earliest discoverer of the rectifying properties of contact between certain solid materials, he was largely responsible and most famous for the development of the crystal detector, the earliest type of diode detector. [2] The crystal detector was the central component in many early radio receivers from around 1906 until about 1920 ...
Galena with baryte and pyrite from Cerro de Pasco, Peru; 5.8 cm × 4.8 cm × 4.4 cm (2.3 in × 1.9 in × 1.7 in) Galena is the main ore of lead, used since ancient times, [6] since lead can be smelted from galena in an ordinary wood fire. [7]
The use of crystal detectors in wavemeters is an interesting fact and should be in the article. But it doesn't change the definition of a crystal detector as a demodulator used in radio receivers to extract the information-bearing audio signal from the radio wave. A wavemeter is a radio receiver, a calibrated receiver used to tune up ...
This is the pyroelectric effect. All polar crystals are pyroelectric, so the 10 polar crystal classes are sometimes referred to as the pyroelectric classes. Pyroelectric materials can be used as infrared and millimeter wavelength radiation detectors. An electret is the electrical equivalent of a permanent magnet.
The pyrite group of minerals is a set of cubic crystal system minerals with diploidal structure. Each metallic element is bonded to six "dumbbell" pairs of non-metallic elements and each "dumbbell" pair is bonded to six metal atoms.