This article is about historical crystal detectors. For modern crystal detectors, see Diode § Radio demodulation.
Galena cat whisker detector used in early crystal radioPrecision 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 is an obsolete electronic component used in some early 20th century radio receivers that consists of a piece of crystalline mineral which rectifies the alternating current radio signal.[1] It was employed as a detector (demodulator) to extract the audio modulation signal from the modulated carrier, to produce the sound in the earphones.[2] It was the first type of semiconductor diode,[3] and one of the first semiconductor electronic devices.[4] The most common type was the so-called cat's whisker detector, which consisted of a piece of crystalline mineral, usually galena (lead sulfide), with a fine wire touching its surface.[1][4][5]
The "asymmetric conduction" of electric current across electrical contacts between a crystal and a metal was discovered in 1874 by Karl Ferdinand Braun.[6] Crystals were first used as radio wave detectors in 1894 by Jagadish Chandra Bose in his microwave experiments.[7][8] Bose first patented a crystal detector in 1901.[9] The crystal detector was developed into a practical radio component mainly by G. W. Pickard,[4][10][11] who discovered crystal rectification in 1902 and found hundreds of crystalline substances that could be used in forming rectifying junctions.[2][12] The physical principles by which they worked were not understood at the time they were used,[13] but subsequent research into these primitive point contact semiconductor junctions in the 1930s and 1940s led to the development of modern semiconductor electronics.[1][4][14][15]
The unamplified radio receivers that used crystal detectors are called crystal radios.[16] The crystal radio was the first type of radio receiver that was used by the general public,[14] and became the most widely used type of radio until the 1920s.[17] It became obsolete with the development of vacuum tube receivers around 1920,[1][14] but continued to be used until World War II and remains a common educational project today thanks to its simple design.
^ abcdCite error: The named reference Braun was invoked but never defined (see the help page).
^ abCite error: The named reference Sievers1 was invoked but never defined (see the help page).
^Cite error: The named reference Hickman was invoked but never defined (see the help page).
^ abcdLee, Thomas H. (2004). Planar Microwave Engineering: A Practical Guide to Theory, Measurement, and Circuits, Vol. 1. Cambridge University Press. pp. 4–9, 297–300. ISBN 978-0521835268.
^U.S. patent 1,104,073 Greenleaf Whittier Pickard, Detector for Wireless Telegraphy and Telephony, filed: 21 June 1911, granted: 21 July 1914
^Orton, John W. (2004). The Story of Semiconductors. Oxford University Press. pp. 20–23. ISBN 978-0198530831.
^Seitz, Frederick; Einspruch, Norman (4 May 1998). The Tangled History of Silicon in Electronics. Silicon Materials Science and Technology: Proceedings of the Eighth International Symposium on Silicon Materials Science and Technology, Vol. 1. San Diego: The Electrochemical Society. pp. 73–74. ISBN 9781566771931. Retrieved 27 June 2018.
^although at the microwave frequencies he used these detectors did not function as rectifying semiconductor diodes like later crystal detectors, but as a thermal detector called a bolometer. Lee, Thomas H. (2004). Planar Microwave Engineering: A Practical Guide to Theory, Measurement, and Circuits, Vol. 1. Cambridge University Press. pp. 4–5. ISBN 978-0521835268.
^U.S. patent 755,840 Jagadis Chunder Bose, Detector for Electrical Disturbances, filed: 30 September 1901, granted 29 March 1904
^U.S. patent 836,531 Greenleaf Whittier Pickard, Means for Receiving Intelligence Communicated by Electric Waves, filed: 30 August 1906, granted: 20 November 1906
^Pickard, Greenleaf Whittier (August 1919). "How I Invented the Crystal Detector" (PDF). Electrical Experimenter. 7 (4): 325–330, 360. Retrieved 13 June 2016.
^Riordan, Michael; Lillian Hoddeson (1988). Crystal fire: the invention of the transistor and the birth of the information age. USA: W. W. Norton & Company. pp. 19–21, 92. ISBN 978-0-393-31851-7.
^ abcBasalla, George (1988). The Evolution of Technology. UK: Cambridge University Press. pp. 44–45. ISBN 978-0-521-29681-6.
^Winston, Brian (2016). Misunderstanding Media. Routledge. pp. 256–259. ISBN 978-1315512198.
^Sterling, Christopher H.; O'Del, Cary (2010). The Concise Encyclopedia of American Radio. Routledge. pp. 199–201. ISBN 978-1135176846.
^"...crystal detectors have been used [in receivers] in greater numbers than any other [type of detector] since about 1907." Marriott, Robert H. (September 17, 1915). "United States Radio Development". Proceedings of the Institute of Radio Engineers. 5 (3): 184. doi:10.1109/jrproc.1917.217311. S2CID 51644366. Retrieved 2010-01-19.
A crystaldetector is an obsolete electronic component used in some early 20th century radio receivers that consists of a piece of crystalline mineral...
component, a crystaldetector, originally made from a piece of crystalline mineral such as galena. This component is now called a diode. Crystal radios are...
Jagadish Chandra Bose was the first to use a crystal for detecting radio waves in 1894. The crystaldetector was developed into a practical device for wireless...
earlier detectors such as the coherer. The crystaldetector was widely used prior to vacuum tubes becoming available. One popular type of crystaldetector, often...
physicist Ferdinand Braun's crystaldetector in 1874 and Indian physicist Jagadish Chandra Bose's radio crystaldetector in 1901. In the years preceding...
and hence the wavelength of the emitted optical photon. A scintillation detector or scintillation counter is obtained when a scintillator is coupled to...
a rectifying detector such as a crystaldetector or electrolytic detector, along with the radio signal from the antenna. In the detector the two signals...
most famous for the development of the crystaldetector, the earliest type of diode detector. The crystaldetector was the central component in many early...
problematic. Crystal scintillator experiments are a middle ground between cryogenic crystaldetectors and noble gas scintillators, using the crystals of the...
"standard" 3″ x 3″ NaI(Tl) scintillation detector. Crystal growth techniques have since improved, allowing detectors to be manufactured that are as large...
physicist Ferdinand Braun's crystaldetector in 1874 and Indian physicist Jagadish Chandra Bose's radio crystaldetector in 1901. The first silicon semiconductor...
operation of his galena crystaldetector in his lectures. A friend in the US persuaded him to take out a US patent on his detector, but he did not actively...
as a mineral detector in radio receivers, and is still used by crystal radio hobbyists. Until the vacuum tube matured, the crystaldetector was the most...
synthetic zincite crystals are significant for their early use as semiconductor crystaldetectors in the early development of crystal radios before the...
used until about 1913, after which it was superseded by crystaldetectors and vacuum tube detectors such as the Fleming valve and Audion (triode). It was...
over the difficulty of adjustment of the crystaldetector and the susceptibility of the crystaldetector to being dislodged from adjustment by vibration...
1907, when they were replaced by more sensitive electrolytic and crystaldetectors. The behavior of particles or metal filings in the presence of electricity...
detector. There are two key aspects to effective neutron detection: hardware and software. Detection hardware refers to the kind of neutron detector used...
magnetron. Adding to their problems was the lack of a suitable rugged crystaldetector, which was the only system able to reliably detect these high frequency...
A phase detector or phase comparator is a frequency mixer, analog multiplier or logic circuit that generates a signal which represents the difference in...
the point-contact crystaldetector (cat's whisker detector), which was used as a demodulator in the first early radio receivers, crystal radios before powered...
(from Greek: pyr (πυρ), "fire" and electricity) is a property of certain crystals which are naturally electrically polarized and as a result contain large...
obsolete technology, the point contact crystaldetector (cat whisker detector) which was used as a demodulator in crystal radios around the turn of the century...
semiconductor detectors, an electric field is applied to the detector volume. An electron in the semiconductor is fixed in its valence band in the crystal until...
for wireless telegraphy, such as the Fleming valve (1904) and the crystaldetector (1906) also proved able to rectify AM signals, so the technological...
of detectors including coherers, barretters, and crystaldetectors. The most popular crystaldetector consisted of a small piece of galena crystal probed...
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