File:Marconi's Coherer Receiver at Oxford Museum History of Science (cropped).jpg
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DescriptionMarconi's Coherer Receiver at Oxford Museum History of Science (cropped).jpg |
English: One of the first radio receivers, constructed by Italian radio inventor Guglielmo Marconi in 1896, on display in the Oxford Museum of the History of Science, UK. It used a coherer, a tube of metal filings, as a radio wave detector, connected to a wire antenna. The coherer is the glass tube on the right. When it detected a radio signal the resistance of the coherer would drop, and DC current from a battery would flow through it and turn on the relay in the cylindrical container at right, ringing a bell. This receiver was used by Marconi in his famous 1896 "black box" demonstration of radio communication at Toynbee hall, London. Caption on card: "Coherer receiver by Guglielmo Marconi, 1896: Marconi used this device for a famous public demonstration of wireless in London's Toynbee Hall in 1896. At a public lecture by William Preece, chief engineer of the General Post Office, whenever Preece switched a transmitter and created an electric spark, a bell rang in a box Marconi took to any part of the lecture room. There was no visible connection between the two. The demonstration caused a sensation and made Marconi a celebrity." |
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Other versions | Marconi's Coherer Receiver at Oxford Museum History of Science.jpg is uncropped version that includes part of transmitter |
Camera location | 51° 45′ 15″ N, 1° 15′ 19″ W | View this and other nearby images on: OpenStreetMap | 51.754167; -1.255278 |
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current | 03:32, 15 December 2015 | 1,671 × 1,806 (395 KB) | Chetvorno (talk | contribs) | User created page with UploadWizard |
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Camera manufacturer | Nokia |
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Camera model | N85 |
Exposure time | 1/20 sec (0.05) |
F-number | f/2.8 |
ISO speed rating | 187 |
Date and time of data generation | 14:42, 28 June 2009 |
Lens focal length | 5.4 mm |
Latitude | 51° 45′ 15″ N |
Longitude | 1° 15′ 19″ W |
Altitude | 100 meters above sea level |
Orientation | Normal |
Horizontal resolution | 72 dpi |
Vertical resolution | 72 dpi |
Y and C positioning | Centered |
Exif version | 2.2 |
Date and time of digitizing | 14:42, 28 June 2009 |
Meaning of each component |
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APEX shutter speed | 4.321 |
APEX aperture | 2.97 |
Light source | Unknown |
Flash | Flash did not fire, compulsory flash suppression |
Supported Flashpix version | 1 |
Color space | sRGB |
Custom image processing | Normal process |
Exposure mode | Auto exposure |
White balance | Auto white balance |
Digital zoom ratio | 1 |
Scene capture type | Standard |
Scene control | Low gain up |
GPS tag version | 0.0.2.2 |