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?
-- Anyone wanting to run for any political office in the US should have to have a DD214, and a honorable discharge.
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.
Michael
Dave is as clueless as Allison. He would freak if he saw a 'carbon amplifier' in operation.
-- Anyone wanting to run for any political office in the US should have to have a DD214, and a honorable discharge.
No, it will crush the quartz, resulting in one spike as it breaks up.
Like a 'Carbon Amplifier'?
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.
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.
-- Anyone wanting to run for any political office in the US should have to have a DD214, and a honorable discharge.
So a relay is an active device?
"Jerry Peters"
** Trying to define a word or term *out of context* is doomed to failure.A relay is not an *electronics* device - it is an electro mechanical one that predates "electronics" by about 100 years.
The invention of the vacuum tube triode kicked it off but the word "electronics" was not applied until the late 1940s - to cover the fields of radio, radar, computers and TV.
It had a previous life as the name of a branch of physics
FYI: if yo want to buy a diode, I suggest you do not waste time looking it up in an electronics catalogue under the heading of "passive components".
.... Phil
There ya go. Forget wiki, Webster's and all that, ask Digikey !
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.
Oscillators do not use one signal to control another. A Gunn diode is a lot like a neon lamp meets quartz crystal. Not a switch. Not an amplifier.
It's a relatively stupid minor point. I looked it up. I am not going to be convinced with silliness like "carbon amplifiers".
A relay is a solenoid (no) and a switch (no).
Sigh. Study that technology, rather than make a fool of yourself. The proper bias creates a negative resistance, which provides gain.
A neon has hysteresis, not gain. They require a current limiting resistor, or they will explode. They turn on at a higher voltage than they turn off so a capacitor across the neon will charge, until the lamp fires. The cap discharges to the extinguishing point, and repeats the cycle. We built sirens with a couple neons, a 35W4 and a 50C5 tube back in the '60s
It's not silly. They were used to provide gain in early days of electronics. It was a carbon mic, coupled do a earpiece. They had plenty of gain. Find an old 500 series desk phone and pull the cotton wadding out of the handle. You'll get feedback. Then there are Magnetic Amplifiers. There is a whole world of electronics you've never seen. How about 'Electrolytic Rectifiers'? They were one of the first crude, but useable ways to convert AC to DC without using a motor/generator set.
But it controls one signal with another.
What about a PIN diode, or even an ordinary switching diode. They've been commonly used to switch an small ac signal with a dc voltage for
*years*.
Or the PIN diode, commonly used to switch rf with a dc voltage.
To get oscillation you need to provide gain to overcome the circuit losses, so you have some type of amplification happening, which implies an active device.
Dave doesn't seem to understand any of this, he just keeps parroting the same words repeatedly.
We should probably apply the "active" or "passive" designation to circuits rather than devices. When we say that a device is active, it means that the only sensible way of using it is in the role where it provides an active circuit.
A passive circuit is one in which the energy source for driving the output signals is derived from the input signals, rather than from some auxiliary power supply.
Anything else is an active circuit.
Because the energy for driving outputs is derived from inputs in a passive device, a passive device can never amplify power; though if it contains inductors, it can step voltage up or down and thereby modify impedance.
A logic inverter circuit built on a relay is definitely active. Justification: the device produces an output which is based on the input, but which does not draw energy from the input at all to power the output. Power is applied to the switch, in series with a load resistor. This energy source is not considered an input signal.
If the relay's switch is used to pass through or cut off a signal (say as part of a multiplexer), then we can regard it as passive. When the signal passes through the relay, it does so without amplification: the output is powered by the input. The next and previous device are not isolated from each other's impedances in any way by the relay; it is transparent. Moreover, the relay's coil is powered by *its* input: the switching mechanism itself does not have its own source of power.
(Note that by the same logic, we could argue that a FET used for signal switching also gives rise to a passive circuit.)
"Jerry Peters"
** I figured you were being facetious.But YOU failed to see the discussion is only about "electronic devices" .
Which relays are not.
.... Phil
?"But YOU failed to see the discussion is only about "electronic devices" .
Which relays are not. "
Why, because they have no silicon or PN junction ? then you rule out tubes/valvs. If the exception is made because of a filament and thermionic emission, then what about gas fired tubes/valves like a 0Z4 or whatever ?
Sometimes the process of elimination is useful. What is NOT an activ device ?
Capacitor Resistor Inductor Switch
That would mean then that a relay is not an active electronic device because the two main compnents are not active.
However, in a transistor....
If a diode is not active, why ? You can modulate with it. You can switch with it. This can be done with solid state diodes or otherwise.
So does the addition of the second junction in a bipolar transistor make it active ? does the addition of a grid in a tube/valve make it active ?
All of this, no matter how useless an argument (nobody has any work to do ?), is coming down to the point where a diode is an active device.
A diode is not active by itself, because it's a two-port circuit. There is no way for it to have an input which controls an output.
No; you also need a circuit to make it active. The minimum active circuit you can make with a three-port device is a three-port current source. Two terminals of the device are placed into a power circuit, and the third terminal controls the flow of current.
Using a three-port transistor or tube triode device, plus some additional components, like at least one resistor, we can make a four-port active circuit based on voltages: something that takes an input voltage on one port, produces an output on another port, and has a third port where power is supplied, so that the input isn't driving the output.
The rule of thumb is: if inputs can control the flow of energy from the outputs, without supplying most of that energy, then the situation is active.
If the output energy is derived from the inputs, then it is passive.
To apply this ide, we have to identify what is an energy source, what are inputs, and what is the output (and in what form).
Example of an active device: power steering in a car. The input is you, turning the wheel, which requires little force because of an energy source within the power steering which actually turns the wheels.
Unpowered steering is passive: all of the energy to move the wheels comes from you, turning the wheel.
(The rack and pinion gives you a mechanical advantage. We have such a passive transmission in electricity also, namely the transformer. Though the transformer adapts impedance and changes voltages and currents, all of the output power comes from the input, so it is passive.)
"Jerry Peters"
** No fooling ?** Out of context again.
Device = single component here.
"Electronic component " is broad church too, it includes anything electronic in nature that is intended to be used to create an electronic device.
Active devices do NOT have to be able to amplify signals - that IS what most of them do but is not the defining issue.
BTW:
I see you are an incorrigible context shifter and a bullshit artist.
Fuck off.
... Phil
s no way for it to have an input which controls an output. "
So your contention then is that tunnel diodes, Gunn diodes and Zener diodes are not active devices.
If that is so, then a magnetron is also passive. It is technically a diode with an indirectly heated cathode unless you consider the magnet an element . Also, what of the case of a Hall effct device ? Nothing electronic contro ls it, only a magnetic field. Other devices can have more than two termina ls aqnd be passive, so where does the Hall effect fit in there ?
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