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Sci.Electronics.Basics -> An "active" device
There are 26 messages in this thread.
You are currently looking at messages 20 to 26.
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Author: Al in DallasDate: 19:00 04-08-07
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On Thu, 02 Aug 2007 21:57:49 -0700, David Harmon <source@netcom.com>
wrote:
>On Fri, 03 Aug 2007 04:35:44 +0100 in sci.electronics.basics, Eeyore
><rabbitsfriendsandrelations@hotmail.com> wrote,
>>
>>Jonathan Kirwan wrote:
>>> Is a diode active or passive under these definitions?
>>
>>A diode is a non-linear resistor and it requires no 'external' power to
>>function. So passive.
>
>How about a tunnel diode?
Is that what we called a Zener diode in Circuits and Electronics 101?
--
Al in St. Lou
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Author: Al in DallasDate: 19:02 04-08-07
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On Fri, 03 Aug 2007 20:19:20 GMT, Rich Grise <rich@example.net> wrote:
>On Fri, 03 Aug 2007 05:04:04 +0000, Michael Black wrote:
>> David Harmon (source@netcom.com) writes:
>>> On Fri, 03 Aug 2007 04:35:44 +0100 in sci.electronics.basics, Eeyore
>>>>Jonathan Kirwan wrote:
>>>>> Is a diode active or passive under these definitions?
>>>>
>>>>A diode is a non-linear resistor and it requires no 'external' power to
>>>>function. So passive.
>>>
>>> How about a tunnel diode?
>>>
>> That's the example I was thinking of that can be both passive
>> and active, depending on useage.
> ^^^^^^
>USAGE!
>
>Misspellings like this really impugn your credibility.
I had a boss who put the word "saute" in his memo. It turned out he
was trying to say "sought." He had a PhD in EE, IIRC.
--
Al in St. Lou
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Author: Al in DallasDate: 19:03 04-08-07
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On Thu, 02 Aug 2007 23:14:49 -0700, Dr. Polemic <nospam@aol.com>
wrote:
>On Fri, 3 Aug 2007 15:01:07 +1000, "Phil Allison"
<philallison@tpg.com.au>
>wrote:
>
>>
>>"David Harmon"
>>
>>>
>>> What exactly is the definition of an "active" device?
>>
>>
>>** The short answer is - there isn't one.
>>
>>The term " active " is a name used to classify strictly electronic
devices
>>as opposed to merely electrical devices and is defined by popular usage,
>>not science.
>>
>>It includes all semiconductors,
>
> Eeyore disagrees with you on this. I think you should insult him.
That was the first civil post I've seen from Mr. Allison. I haven't
been around long.
--
Al in St. Lou
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Author: JeffMDate: 19:26 04-08-07
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Author: Bob MyersDate: 19:28 04-08-07
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"Al in Dallas" <alfargnoli@yahoo.com> wrote in message
news:471ab3leutlon9248vve9rhkpo1b9vlo4v@4ax.com...
>>How about a tunnel diode?
>
> Is that what we called a Zener diode in Circuits and Electronics 101?
No, it isn't.
Tunnel diodes aren't seen all that often any more in more
mainstream products, but they're basically diodes that have
a "negative resistance" region in their forward operation
curve (i.e., a part of the curve in which the forward
current decreases with increasing forward voltage).
They are used for applications requiring extremely fast
switching speeds, and in very high-frequency amplifiers
and oscillators.
A Zener diode, on the other hand, is one which has been
made so as to have a very abrupt reverse breakdown,
and typically one which occurs at a relatively low voltage.
As such, they're useful as voltage references, limiters, etc..
Bob M.
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Author: Al in DallasDate: 23:17 04-08-07
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On Sat, 04 Aug 2007 16:26:22 -0700, JeffM <jeffm_@email.com> wrote:
>David Harmon wrote:
>>>How about a tunnel diode?
>>>
>Al in Dallas wrote:
>>Is that what we called a Zener diode in Circuits and Electronics 101?
>> Al in St. Lou
>
>No.
>http://www.google.com/search?q=cache:bnkhXtHtLf4J:en.wikipedia.org/wiki/Tunnel_diode
+in.the.reverse.direction+501+forward.bias.operation+501+also.occurs+offset.voltage+negati
ve.resistance+extreme.linearity+zero
>(These things are easily Googled.)
Amazing. Thanks.
--
Al in St. Lou
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