Matches in DBpedia 2016-04 for { <http://dbpedia.org/resource/Crystal_radio> ?p ?o }
- Crystal_radio abstract "A crystal radio receiver, also called a crystal set or cat's whisker receiver, is a very simple radio receiver, popular in the early days of radio. It needs no other power source but that received solely from the power of radio waves received by a wire antenna. It gets its name from its most important component, known as a crystal detector, originally made from a piece of crystalline mineral such as galena. This component is now called a diode.Crystal radios are the simplest type of radio receiver and can be made with a few inexpensive parts, such as a wire for an antenna, a coil of copper wire for adjustment, a capacitor, a crystal detector, and earphones. They are distinct from ordinary radios as they are passive receivers, while other radios use a separate source of electric power such as a battery or the mains power to amplify the weak radio signal so as to make it louder. Thus, crystal sets produce rather weak sound and must be listened to with sensitive earphones, and can only receive stations within a limited range.The rectifying property of crystals was discovered in 1874 by Karl Ferdinand Braun, and crystal detectors were developed and applied to radio receivers in 1904 by Jagadish Chandra Bose, G. W. Pickard and others.Crystal radios were the first widely used type of radio receiver, and the main type used during the wireless telegraphy era. Sold and homemade by the millions, the inexpensive and reliable crystal radio was a major driving force in the introduction of radio to the public, contributing to the development of radio as an entertainment medium around 1920.After about 1920, crystal sets were superseded by the first amplifying receivers, which used vacuum tubes (Audions), and became obsolete for commercial use. They continued to be built by hobbyists, youth groups, and the Boy Scouts however, as a way of learning about the technology of radio. Today they are still sold as educational devices, and there are groups of enthusiasts devoted to their construction who hold competitions comparing the performance of their home-built designs.Crystal radios receive amplitude modulated (AM) signals, and can be designed to receive almost any radio frequency band, but most receive the AM broadcast band. A few receive shortwave bands, but strong signals are required. The first crystal sets received wireless telegraphy signals broadcast by spark-gap transmitters at frequencies as low as 20 kHz.".
- Crystal_radio thumbnail Crystal_radio_enthusiast.JPG?width=300.
- Crystal_radio wikiPageExternalLink books?id=k8Wpg2wxDLcC.
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- Crystal_radio wikiPageExternalLink xtal.htm.
- Crystal_radio wikiPageExternalLink cristadyne.html.
- Crystal_radio wikiPageExternalLink www.bentongue.com.
- Crystal_radio wikiPageExternalLink cats-whisker-crystal-types.php.
- Crystal_radio wikiPageExternalLink crystalradio.htm.
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- Crystal_radio wikiPageExternalLink www.vcomp.co.uk.
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- Crystal_radio wikiPageRevisionID "707898008".
- Crystal_radio wikiPageWikiLink AM_broadcasting.
- Crystal_radio wikiPageWikiLink Alexanderson_alternator.
- Crystal_radio wikiPageWikiLink Allies_of_World_War_II.
- Crystal_radio wikiPageWikiLink Alternating_current.
- Crystal_radio wikiPageWikiLink Amateur_radio_operator.
- Crystal_radio wikiPageWikiLink Amplifier.
- Crystal_radio wikiPageWikiLink Amplitude_modulation.
- Crystal_radio wikiPageWikiLink Antenna_(radio).
- Crystal_radio wikiPageWikiLink Antenna_tuner.
- Crystal_radio wikiPageWikiLink Anzio.
- Crystal_radio wikiPageWikiLink Arc_converter.
- Crystal_radio wikiPageWikiLink Audio_signal.
- Crystal_radio wikiPageWikiLink Audion.
- Crystal_radio wikiPageWikiLink Autotransformer.
- Crystal_radio wikiPageWikiLink BBC.
- Crystal_radio wikiPageWikiLink Band-pass_filter.
- Crystal_radio wikiPageWikiLink Bandwidth_(signal_processing).
- Crystal_radio wikiPageWikiLink Barbed_wire.
- Crystal_radio wikiPageWikiLink Battery_(electricity).
- Crystal_radio wikiPageWikiLink Batteryless_radio.
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- Crystal_radio wikiPageWikiLink Boy_Scouts_of_America.
- Crystal_radio wikiPageWikiLink Broadcasting.
- Crystal_radio wikiPageWikiLink Buzzer.
- Crystal_radio wikiPageWikiLink Camille_Tissot.
- Crystal_radio wikiPageWikiLink Capacitance.
- Crystal_radio wikiPageWikiLink Capacitor.
- Crystal_radio wikiPageWikiLink Carbon_microphone.
- Crystal_radio wikiPageWikiLink Carrier_wave.
- Crystal_radio wikiPageWikiLink Category:Amateur_radio_receivers.
- Crystal_radio wikiPageWikiLink Category:Electronic_design.
- Crystal_radio wikiPageWikiLink Category:History_of_radio.
- Crystal_radio wikiPageWikiLink Category:Radio_electronics.
- Crystal_radio wikiPageWikiLink Category:Receiver_(radio).
- Crystal_radio wikiPageWikiLink Category:Types_of_radios.
- Crystal_radio wikiPageWikiLink Cats-whisker_detector.
- Crystal_radio wikiPageWikiLink Coherer.
- Crystal_radio wikiPageWikiLink Competition.
- Crystal_radio wikiPageWikiLink Counterpoise_(ground_system).
- Crystal_radio wikiPageWikiLink Crystal_earpiece.
- Crystal_radio wikiPageWikiLink Current–voltage_characteristic.
- Crystal_radio wikiPageWikiLink DXing.
- Crystal_radio wikiPageWikiLink Decoupling_capacitor.
- Crystal_radio wikiPageWikiLink Demodulation.
- Crystal_radio wikiPageWikiLink Detector_(radio).
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- Crystal_radio wikiPageWikiLink Direct_current.
- Crystal_radio wikiPageWikiLink Electric_current.
- Crystal_radio wikiPageWikiLink Electric_power.
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- Crystal_radio wikiPageWikiLink Electrolytic_detector.
- Crystal_radio wikiPageWikiLink Electromagnet.
- Crystal_radio wikiPageWikiLink Fad.
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- Crystal_radio wikiPageWikiLink File:GWP-836531Patent.png.
- Crystal_radio wikiPageWikiLink File:NBS_120_Set.jpg.
- Crystal_radio wikiPageWikiLink Fire_escape.
- Crystal_radio wikiPageWikiLink Folklore.
- Crystal_radio wikiPageWikiLink Foxhole_radio.
- Crystal_radio wikiPageWikiLink Frequency.
- Crystal_radio wikiPageWikiLink Galena.
- Crystal_radio wikiPageWikiLink Greenleaf_Whittier_Pickard.
- Crystal_radio wikiPageWikiLink Ground_(electricity).
- Crystal_radio wikiPageWikiLink Headphones.
- Crystal_radio wikiPageWikiLink Hearing.
- Crystal_radio wikiPageWikiLink Hearing_aid.
- Crystal_radio wikiPageWikiLink High_fidelity.
- Crystal_radio wikiPageWikiLink History_of_radio.
- Crystal_radio wikiPageWikiLink Hobby.
- Crystal_radio wikiPageWikiLink Impedance_matching.
- Crystal_radio wikiPageWikiLink Inductance.
- Crystal_radio wikiPageWikiLink Inductor.
- Crystal_radio wikiPageWikiLink Input_impedance.
- Crystal_radio wikiPageWikiLink Jagadish_Chandra_Bose.
- Crystal_radio wikiPageWikiLink KDKA_(AM).
- Crystal_radio wikiPageWikiLink Karl_Ferdinand_Braun.
- Crystal_radio wikiPageWikiLink LC_circuit.