Diodes
A cat's-whisker detector (sometimes called a crystal detector) is an antique electronic component consisting of a thin wire that lightly touches a crystal of semiconducting mineral
(usually galena) to make a crude point-contact rectifier. Developed by early radio researchers Henry
H. C. Dunwoody, G. W. Pickard and others, this device was used as the detector in early crystal radios, from about 1906 through the Second World War, and gave this type of radio receiver its name. Crystal radios were the most popular type of radio until the mid 1920s. The cat's whisker detector was the first type of semiconductor diode, and in fact, the first semiconductor electronic device. Cat's whisker detectors are obsolete and are now only used in antique or antiquereproduction radios, and for educational purposes.
Tunnel diode
From Wikipedia, the free encyclopedia
Tunnel diode schematic symbol
1N3716 tunnel diode (with 0.1" jumper for scale)
10mA germanium tunnel diode mounted in test fixture of Tektronix 571 curve tracer
A tunnel diode or Esaki diode is a type of semiconductor that is capable of very fast operation, well into the microwave frequencyregion, made possible by the use of the quantum mechanical effect called tunneling.
It was invented in August 1957 by Leo Esaki when he was with Tokyo Tsushin Kogyo, now known as Sony. In 1973 he received theNobel Prize in Physics, jointly with Brian Josephson, for discovering the electron tunneling effect used in these diodes. Robert Noyceindependently came up with the idea of a tunnel diode while working for William Shockley, but was discouraged from pursuing it.[1]
These diodes have a heavily doped p–n junction only some 10 nm (100 Å) wide. The heavy doping results in a broken bandgap, whereconduction band electron states on the n-side are more or less aligned with valence band hole states on the p-side
Tunnel diodes were first manufactured by Sony in 1957[2] followed by General Electric and other companies from about 1960, and
(usually galena) to make a crude point-contact rectifier. Developed by early radio researchers Henry
H. C. Dunwoody, G. W. Pickard and others, this device was used as the detector in early crystal radios, from about 1906 through the Second World War, and gave this type of radio receiver its name. Crystal radios were the most popular type of radio until the mid 1920s. The cat's whisker detector was the first type of semiconductor diode, and in fact, the first semiconductor electronic device. Cat's whisker detectors are obsolete and are now only used in antique or antiquereproduction radios, and for educational purposes.
Tunnel diode
From Wikipedia, the free encyclopedia
Tunnel diode schematic symbol
1N3716 tunnel diode (with 0.1" jumper for scale)
10mA germanium tunnel diode mounted in test fixture of Tektronix 571 curve tracer
A tunnel diode or Esaki diode is a type of semiconductor that is capable of very fast operation, well into the microwave frequencyregion, made possible by the use of the quantum mechanical effect called tunneling.
It was invented in August 1957 by Leo Esaki when he was with Tokyo Tsushin Kogyo, now known as Sony. In 1973 he received theNobel Prize in Physics, jointly with Brian Josephson, for discovering the electron tunneling effect used in these diodes. Robert Noyceindependently came up with the idea of a tunnel diode while working for William Shockley, but was discouraged from pursuing it.[1]
These diodes have a heavily doped p–n junction only some 10 nm (100 Å) wide. The heavy doping results in a broken bandgap, whereconduction band electron states on the n-side are more or less aligned with valence band hole states on the p-side
Tunnel diodes were first manufactured by Sony in 1957[2] followed by General Electric and other companies from about 1960, and