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John Woodgate
electronics forum Guru
Joined: 24 Mar 2005
Posts: 1546
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 Posted: Thu Oct 13, 2005 9:23 pm Post subject:
Re: Driver for IGBT? (-ve off and +ve on from CMOS)
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I read in sci.electronics.design that Ignoramus13229
<ignoramus13229@NOSPAM.13229.invalid> wrote (in
<dimhnh$klc$1@pita.alt.net>) about 'Driver for IGBT? (-ve off and +ve on
from CMOS)', on Thu, 13 Oct 2005:
| Quote: | That's for sure. On the other hand, I am not doing it completely alone,
there is plenty of people who already showed their ability to set me on
the straight and narrow.
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They are good at explaining how you walk a tightrope. But it will be you
that is 50ft up without a safety net.
--
Regards, John Woodgate, OOO - Own Opinions Only.
If everything has been designed, a god designed evolution by natural selection.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk |
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Glen Walpert
electronics forum Guru Wannabe
Joined: 04 May 2005
Posts: 134
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| Posted: Thu Oct 13, 2005 9:24 pm Post subject:
Re: Driver for IGBT? (-ve off and +ve on from CMOS)
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On 13 Oct 2005 11:47:16 -0700, Winfield Hill
<Winfield_member@newsguy.com> wrote:
| Quote: | Glen Walpert wrote...
Well at least he should be well under a kJ. Although I previously
guessed that his inductor was on the order of 10 uH, that was a typo,
I meant 10 mH. I see that Hobart uses the classic 6 phase double-Y
connection with interphase transformer, so the SCRs fire 6 times per
cycle or every 2.8 ms, and if the inductor is sized to allow current
decay of 5 amps at 20 volts in 2.5 msec then the inductor would be 20
volts / 2000 volt/sec = 10 mH. They might easily have designed for
less ripple but probably not less than 1 amp, for a 50 mH reactor.
So with a short circuit current of say 400 amps he only has 20 joules
to dump somewhere unless I screwed up again  .
20J? E = 0.5 LI^2 = 0.5 0.01 400A^2 = 800J. With 50mH, 4000J.
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<blush> I hope i is paying closer attention than I am! And I hope he
wears good protective gear, sooner or later those IGBTs are bound to
try to shut off at high current. |
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Ignoramus25589
electronics forum beginner
Joined: 13 Oct 2005
Posts: 13
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| Posted: Thu Oct 13, 2005 11:37 pm Post subject:
Re: Driver for IGBT? (-ve off and +ve on from CMOS)
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On Thu, 13 Oct 2005 20:28:18 GMT, Rich Grise <rich@example.net> wrote:
| Quote: |
I'm sorry if I sound harsh or condescending here, but if you can take
a DC welder and an H-bridge and get AC to come out of it without
dramatically hacking the welder itself, then more power to you, and
I'd really like to see it. Don't forget - when you're DCEN, your
whole welder and workpiece are positive ground. When you're DCEP,
your whole welder and workpiece are negative ground. So you not
only have to run AC to the electrode, you have to have the whole
welder and workpiece going from negative to positive at your pulse
rate.
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That's actually incorrect. I verified it with an ohmmeter. The work
terminal is not connected to equipment body/equipment ground.
There is infinite resistance between both work and stick terminals and
the welder.
I can flip flop the polarity all I want, without affecting the
welder's grounding in any way.
I kind of expected that to be the case, for obvious safety reasons.
i |
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Rich, Under the Affluence
electronics forum Guru Wannabe
Joined: 17 Sep 2005
Posts: 197
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| Posted: Fri Oct 14, 2005 12:44 am Post subject:
Re: Driver for IGBT? (-ve off and +ve on from CMOS)
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On Thu, 13 Oct 2005 22:23:37 +0100, John Woodgate wrote:
| Quote: | I read in sci.electronics.design that Ignoramus13229
ignoramus13229@NOSPAM.13229.invalid> wrote (in
dimhnh$klc$1@pita.alt.net>) about 'Driver for IGBT? (-ve off and +ve on
from CMOS)', on Thu, 13 Oct 2005:
That's for sure. On the other hand, I am not doing it completely alone,
there is plenty of people who already showed their ability to set me on
the straight and narrow.
They are good at explaining how you walk a tightrope. But it will be you
that is 50ft up without a safety net.
|
Vaguely reminiscent of sky-diving ground school - the instructor is
taking you through the training, while you're hanging on the harness,
and he says, "Malfunction!" You look at the instructor, like "WTF?"
and he says, "Don't look at me! When you're up there, there's nobody
to talk to but God, and he don't talk to skydivers, 'cause he thinks
we're crazy."
Cheers!
Rich |
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Ignoramus25589
electronics forum beginner
Joined: 13 Oct 2005
Posts: 13
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| Posted: Fri Oct 14, 2005 2:30 am Post subject:
Re: Driver for IGBT? (-ve off and +ve on from CMOS)
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On Fri, 14 Oct 2005 00:44:14 GMT, Rich, Under the Affluence <nevermind@example.net> wrote:
| Quote: | On Thu, 13 Oct 2005 22:23:37 +0100, John Woodgate wrote:
I read in sci.electronics.design that Ignoramus13229
ignoramus13229@NOSPAM.13229.invalid> wrote (in
dimhnh$klc$1@pita.alt.net>) about 'Driver for IGBT? (-ve off and +ve on
from CMOS)', on Thu, 13 Oct 2005:
That's for sure. On the other hand, I am not doing it completely alone,
there is plenty of people who already showed their ability to set me on
the straight and narrow.
They are good at explaining how you walk a tightrope. But it will be you
that is 50ft up without a safety net.
Vaguely reminiscent of sky-diving ground school - the instructor is
taking you through the training, while you're hanging on the harness,
and he says, "Malfunction!" You look at the instructor, like "WTF?"
and he says, "Don't look at me! When you're up there, there's nobody
to talk to but God, and he don't talk to skydivers, 'cause he thinks
we're crazy."
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I skydived once, it ws quite a harrowing experience. Well worth $75.
i |
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Ignoramus25589
electronics forum beginner
Joined: 13 Oct 2005
Posts: 13
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| Posted: Fri Oct 14, 2005 2:43 am Post subject:
Re: Driver for IGBT? (-ve off and +ve on from CMOS)
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On Thu, 13 Oct 2005 22:46:44 -0400, Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> wrote:
| Quote: | On Fri, 14 Oct 2005 02:30:50 GMT, the renowned Ignoramus25589
ignoramus25589@NOSPAM.25589.invalid> wrote:
On Fri, 14 Oct 2005 00:44:14 GMT, Rich, Under the Affluence <nevermind@example.net> wrote:
On Thu, 13 Oct 2005 22:23:37 +0100, John Woodgate wrote:
I read in sci.electronics.design that Ignoramus13229
ignoramus13229@NOSPAM.13229.invalid> wrote (in
dimhnh$klc$1@pita.alt.net>) about 'Driver for IGBT? (-ve off and +ve on
from CMOS)', on Thu, 13 Oct 2005:
That's for sure. On the other hand, I am not doing it completely alone,
there is plenty of people who already showed their ability to set me on
the straight and narrow.
They are good at explaining how you walk a tightrope. But it will be you
that is 50ft up without a safety net.
Vaguely reminiscent of sky-diving ground school - the instructor is
taking you through the training, while you're hanging on the harness,
and he says, "Malfunction!" You look at the instructor, like "WTF?"
and he says, "Don't look at me! When you're up there, there's nobody
to talk to but God, and he don't talk to skydivers, 'cause he thinks
we're crazy."
I skydived once, it ws quite a harrowing experience. Well worth $75.
i
Enough with the TIG-- I'd rather spend the $10K to fly a MIG.
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Let's come up with a way to weaponize IGBTs...
i |
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Spehro Pefhany
electronics forum Guru
Joined: 01 May 2005
Posts: 2326
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| Posted: Fri Oct 14, 2005 2:46 am Post subject:
Re: Driver for IGBT? (-ve off and +ve on from CMOS)
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On Fri, 14 Oct 2005 02:30:50 GMT, the renowned Ignoramus25589
<ignoramus25589@NOSPAM.25589.invalid> wrote:
| Quote: | On Fri, 14 Oct 2005 00:44:14 GMT, Rich, Under the Affluence <nevermind@example.net> wrote:
On Thu, 13 Oct 2005 22:23:37 +0100, John Woodgate wrote:
I read in sci.electronics.design that Ignoramus13229
ignoramus13229@NOSPAM.13229.invalid> wrote (in
dimhnh$klc$1@pita.alt.net>) about 'Driver for IGBT? (-ve off and +ve on
from CMOS)', on Thu, 13 Oct 2005:
That's for sure. On the other hand, I am not doing it completely alone,
there is plenty of people who already showed their ability to set me on
the straight and narrow.
They are good at explaining how you walk a tightrope. But it will be you
that is 50ft up without a safety net.
Vaguely reminiscent of sky-diving ground school - the instructor is
taking you through the training, while you're hanging on the harness,
and he says, "Malfunction!" You look at the instructor, like "WTF?"
and he says, "Don't look at me! When you're up there, there's nobody
to talk to but God, and he don't talk to skydivers, 'cause he thinks
we're crazy."
I skydived once, it ws quite a harrowing experience. Well worth $75.
i
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Enough with the TIG-- I'd rather spend the $10K to fly a MIG.
Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com |
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Robert Latest
electronics forum Guru
Joined: 09 May 2005
Posts: 304
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| Posted: Fri Oct 14, 2005 8:31 am Post subject:
Re: Driver for IGBT? (-ve off and +ve on from CMOS)
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On Fri, 14 Oct 2005 02:43:19 GMT,
Ignoramus25589 <ignoramus25589@NOSPAM.25589.invalid> wrote
in Msg. <bXE3f.6$%T1.3@fe37.usenetserver.com>
| Quote: | Let's come up with a way to weaponize IGBTs...
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Your TIG project will be a good start ;-)
robert |
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Rich the Newsgroup Wacko
electronics forum addict
Joined: 21 May 2005
Posts: 51
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| Posted: Fri Oct 14, 2005 3:31 pm Post subject:
Re: Driver for IGBT? (-ve off and +ve on from CMOS)
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On Fri, 14 Oct 2005 02:43:19 +0000, Ignoramus25589 wrote:
| Quote: | On Thu, 13 Oct 2005 22:46:44 -0400, Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> wrote:
On Fri, 14 Oct 2005 02:30:50 GMT, the renowned Ignoramus25589
On Fri, 14 Oct 2005 00:44:14 GMT, Rich, Under the Affluence <nevermind@example.net> wrote:
On Thu, 13 Oct 2005 22:23:37 +0100, John Woodgate wrote:
I read in sci.electronics.design that Ignoramus13229
That's for sure. On the other hand, I am not doing it completely alone,
there is plenty of people who already showed their ability to set me on
the straight and narrow.
They are good at explaining how you walk a tightrope. But it will be you
that is 50ft up without a safety net.
Vaguely reminiscent of sky-diving ground school - the instructor is
taking you through the training, while you're hanging on the harness,
and he says, "Malfunction!" You look at the instructor, like "WTF?"
and he says, "Don't look at me! When you're up there, there's nobody
to talk to but God, and he don't talk to skydivers, 'cause he thinks
we're crazy."
I skydived once, it ws quite a harrowing experience. Well worth $75.
Enough with the TIG-- I'd rather spend the $10K to fly a MIG.
|
$10K for a MIG? Heck, go FCAW, you don't need the argon. 
http://www.millerwelds.com/products/mig/
| Quote: | Let's come up with a way to weaponize IGBTs...
|
Remember when they invented the ICBM? Everybody thought it was the
latest and greatest, until some congressman from Alaska said, "What's
the big deal? The Eskimos have been having ICBMs for years!"
--
Cheers!
Rich
------
"There was a young fellow named Blaine,
And he screwed some disgusting old jane.
She was ugly and smelly
With an awful pot-belly,
But... well, they were caught in the rain." |
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John Woodgate
electronics forum Guru
Joined: 24 Mar 2005
Posts: 1546
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| Posted: Fri Oct 14, 2005 3:59 pm Post subject:
Re: Driver for IGBT? (-ve off and +ve on from CMOS)
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I read in sci.electronics.design that Rich the Newsgroup Wacko
<gfy@example.net> wrote (in
<pan.2005.10.14.15.35.02.848673@example.net>) about 'Driver for IGBT?
(-ve off and +ve on from CMOS)', on Fri, 14 Oct 2005:
| Quote: | Remember when they invented the ICBM? Everybody thought it was the
latest and greatest, until some congressman from Alaska said, "What's
the big deal? The Eskimos have been having ICBMs for years!"
|
Must have been a Republican; he said 'Eskimo'. Very non-PC.(
--
Regards, John Woodgate, OOO - Own Opinions Only.
If everything has been designed, a god designed evolution by natural selection.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk |
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lima-sz
electronics forum beginner
Joined: 06 Dec 2007
Posts: 4
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| Posted: Thu Dec 06, 2007 4:44 am Post subject:
〓what is semiconductor?〓
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〓what is semiconductor?〓
Overview
Semiconductors are very similar to insulators. The two categories of solids differ primarily in that insulators have larger band gaps — energies that electrons must acquire to be free to flow. In semiconductors at room temperature, just as in insulators, very few electrons gain enough thermal energy to leap the band gap, which is necessary for conduction. For this reason, pure semiconductors and insulators, in the absence of applied fields, have roughly similar electrical properties. The smaller bandgaps of semiconductors, however, allow for many other means besides temperature to control their electrical properties.
Semiconductors' intrinsic electrical properties are very often permanently modified by introducing impurities, in a process known as doping. Usually it is reasonable to approximate that each impurity atom adds one electron or one "hole" (a concept to be discussed later) that may flow freely. Upon the addition of a sufficiently large proportion of dopants, semiconductors conduct electricity nearly as well as metals. The junctions between regions of semiconductors that are doped with different impurities contain built-in electric fields, which are critical to semiconductor device operation.
In addition to permanent modification through doping, the electrical properties of semiconductors are often dynamically modified by applying electric fields. The ability to control conductivity in small and well-defined regions of semiconductor material, statically through doping and dynamically through the application of electric fields, has led to the development of a broad array of semiconductor devices, like transistors. Semiconductor devices with dynamically controlled conductivity are the building blocks of integrated circuits, like the microprocessor. These "active" semiconductor devices are combined with simpler passive components, such as semiconductor capacitors and resistors, to produce a variety of electronic devices.
In certain semiconductors, when electrons fall from the conduction band to the valence band (the energy levels above and below the band gap), they often emit light. This photoemission process underlies the light-emitting diode (LED) and the semiconductor laser, both of which are tremendously important commercially. Conversely, semiconductor absorption of light in photodetectors excites electrons from the valence band to the conduction band, facilitating reception of fiber optic communications, and providing the basis for energy from solar cells.
Semiconductors may be elemental materials, such as silicon, compound semiconductors such as gallium arsenide, or alloys, such as silicon germanium or aluminium gallium arsenide.
Energy-momentum dispersion
In the preceding description an important fact is ignored for the sake of simplicity: the dispersion of the energy. The reason that the energies of the states are broadened into a band is that the energy depends on the value of the wave vector, or k-vector, of the electron. The k-vector, in quantum mechanics, is the representation of the momentum of a particle. The E-k relationship varies from material to material.
The effective mass is important as it effects many of the electrical properties of the semiconductor, such as the electron or hole mobility, which in turn influences the diffusivity of the charge carriers and the electrical conductivity of the semiconductor.
Typically the effective mass of electrons and holes are different. This affects the relative performance of p-channel and n-channel IGFETs, for example (Muller & Kamins 1986:427).
The top of the valence band and the bottom of the conduction band might not occur at that same value of k. Materials with this situation, such as silicon and germanium, are known as indirect bandgap materials. Materials in which the band extrema are aligned in k, for example gallium arsenide, are called direct bandgap semiconductors. Direct gap semiconductors are particularly important in optoelectronics because they are much more efficient as light emitters than indirect gap materials.
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