dave wrote:

On 01/23/2014 06:05 PM, Michael A. Terrell wrote:

dave wrote:

On 01/23/2014 06:45 AM, Michael A. Terrell wrote:


It is not a switch or a valve.


It's a solid state diode that oscillates. DC in, and ~10 GHZ out.
Search on Gunnplexer. You see them on automatic doors in almost every
store. A microwave mixer diode takes a sample from the Gunn diode and
compares it to any reflected signals. This results in a low frequency
signal that is detected, amplified and signals the door to open. How
can a passive diode do that?


Like I said. You can hit a piece of quartz with a hammer and it will
oscillate; that doesn't mean it's considered and active device.


No, it will crush the quartz, resulting in one spike as it breaks up.


An active device uses one signal [current, voltage] to control another.


Like a 'Carbon Amplifier'?


As in amplify or switch. Thermionic valve, transistor, SCR, Triac is
what we are going for.


A rectifier is a switch. Diodes are used as mixers, and the
rectifiers a poorly designed power supply can generate RF that is
coupled into the power line.


Sigh. Small minds like yours will never learn anything.

http://en.wikipedia.org/wiki/Gunn_diode


The Gunn diode is based on the Gunn effect, and both are named for the
physicist J. B. Gunn who, at IBM in 1962, discovered the effect because
he refused to accept inconsistent experimental results in gallium
arsenide as "noise", and tracked down the cause. Alan Chynoweth, of Bell
Telephone Laboratories, showed in June 1965 that only a
transferred-electron mechanism could explain the experimental
results.[3] The interpretation refers to the Ridley-Watkins-Hilsum
theory.

The Gunn effect, and its relation to the Watkins-Ridley-Hilsum effect
entered the monograph literature in the early 1970s, e.g. in books on
transferred electron devices[4] and, more recently on nonlinear wave
methods for charge transport.[5] Several other books that provided the
same coverage were published in the intervening years, and can be found
by searching library and bookseller catalogues on Gunn effect.




http://en.wikipedia.org/wiki/Esaki_diode AKA Tunnel diode was invented
in 1958. It was used as a 14 GHz amplifier in Intelsat V satellite
receiver.


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