Theo, fellow philosophers,
Sorry, I know this is getting even further afield, but way too much physics
content in Theo's posting for me not to comment. Theo's comment about a
hole being a "theoretical construct" got me questioning if a hole is really
any less "real" than an electron. Certainly the electron has a bit more
status being a recognized subatomic particle in the lepton family. But has
anyone actually ever seen one? And their behavior is very peculiar;
sometimes they act like tiny particles and sometimes like waves spread out
in space. All of these behaviors are mathematical constructs as well. I
think the real story is that we have become very familiar with "electrons",
and with familiarity comes the illusion of understanding. The idea of a
"hole" is just a little less familiar, but probably really no more
mysterious or less real than the electron. Meanwhile, physicists on the
growing edge of science still debate the meaning of some of the seeming
paradoxes in the behavior of electrons while engineers keep finding more
interesting ways to use them for our amusement and amazement.
Bob
At 08:30 AM 1/29/99 -0700, Theo Smit wrote:
>This is only slightly related to the original topic, and 'way off the deep end
>in terms of how relevant it is to everyday life, but... In semiconductor
>physics, a 'hole' is a theoretical construct used to calculate transistor (or
>diode, or FET) performance. As many of you no doubt know. transistors are
>commonly available in 'NPN' or 'PNP' types. In NPN transistors electrons are
>largely responsible for the current flow and gain characteristics, while in a
>PNP transistor, the 'holes' determine the current and gain. The interesting
>thing (if you're an electro-geek like me) is that electron mobility is about
>three times as large as hole mobility, which means that a PNP (or for similar
>reasons, a P-channel MOSFET) transistor has to be significantly larger than an
>NPN type to give equivalent performance.
>
>The circuits in which NPN transistors are used typically use the most negative
>potential as the 'common' between the various portions of the circuit, but the
>switch to negative ground in automobiles predates the use of electronics by
>about a decade.
>
>Theo Smit
>tsmit@novatel.ca
>B382002705
>> -----Original Message-----
>> From: Steve Laifman [SMTP:laifman@flash.net]
>> Sent: Thursday, January 28, 1999 8:59 PM
>> To: Mark Rudnicki
>> Cc: tigers@autox.team.net
>> Subject: Re: Positive and/or negative earth: Why on earth?
>>
>>
>>
>> Mark Rudnicki wrote:
>>
>> > Someone once told me that there is actually something that does flow
>> > from the positive to the negative side of a circuit, and that is a
>> > "hole", or a positively charged particle that somehow shows up when an
>> > electron gets moved. ........ But I digress...
>> >
>> > Mark Rudnicki
>>
>> The 'something' that moves from the 'positive' to the 'negative' terminal
>> is called 'current' (or 'amps').
>>
>> Electrons, not caring what man's inaccurate understanding of it's nature
>> is, merrily flows from the abundance at the negative pole 'downhill' to the
>> 'sink', or positive pole.
>>
>> It really doesn't matter, except in some instances of galvanic corrosion in
>> pipes, but not on our rubber tired cars. Unless, of course, you use the
>> wrong component. Then all the smoke leaks out.
>> --
>> Steve Laifman < One first kiss, >
>> B9472289 < one first love, and >
>> < one first win, is all >
>> < you get in this life. >
>>
>>
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>>
Robert L. Palmer
Dept. of AMES, Univ. of Calif., San Diego
rpalmer@ames.ucsd.edu
rpalmer@cts.com
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