On 01/24/2014 03:09 PM, Michael A. Terrell wrote:

Michael Black wrote:

On Fri, 24 Jan 2014, 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. An active
device uses one signal [current, voltage] to control another. As in amplify
or switch. Thermionic valve, transistor, SCR, Triac is what we are going for.


I can't keep track of this argument.

But, that piece of quartz, the output will start decaying in volume almost
immediately. It requires an active device to keep that going.


Dave is as clueless as Allison. He would freak if he saw a 'carbon
amplifier' in operation.


I will cop to "clueless". That's why I look stuff up first. A tube,or a
transistor (any gated device really) is an active device. They control
one current with another. They amplify. They switch. They invert
polarity sometimes.