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Old 18th January 2003, 08:19 PM   #11
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Talking NOTHING

Quote:
Originally posted by dimitri
Hey guys, may be it will be good idea to start new Forums named halojoy and Elso Kwak, where you can put your opinions on nothing and compete with the number of posts? Are all the pubs closed in your city? No girls to piffle with?
Hi Dimitri, Halojoy is the clear winner with over 1000 posts. I am just over 500. I am too old to piffle with girls.

And from a other thread with halojoy, Dimitri,
"I know nothing, I am from Barcelona, I know noooothing!"
[joke]
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Old 18th January 2003, 08:25 PM   #12
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Lightbulb Full complementary amplifier

Quote:
Originally posted by kevin gilmore
quote

Fully complementary, symmetric amplifiers do not exist.
Not with todays transistors.


I totally disagree. A fully complementary amp can be built
as long as it is fully balanced input and fully balanced
(i.e. H bridge) output.

Every signal ends up going thru the exact same amount
of pnp and npn transistors. The resulting rise and fall
slew rates are absolutely identical.
Hi kevin,
I agree with you. You mean something like Ampzilla III?. Full bridged amplifier. Still asking myself if the Ampzilla 2000 is using this scheme. Mr Bongiorno is very reluctant in giving circuit details.
http://home.kimo.com.tw/skychutw/amp...llaIII_sch.gif
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Old 19th January 2003, 01:32 PM   #13
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elso_kwak, your ampzilla link does not work...

Here is what i'm talking about

http://gilmore.chem.northwestern.edu/uberpage5.jpg

also most of the rest of it
http://gilmore.chem.northwestern.edu/uberpage1.jpg
http://gilmore.chem.northwestern.edu/uberpage2.jpg
http://gilmore.chem.northwestern.edu/uberpage3.jpg
http://gilmore.chem.northwestern.edu/uberpage4.jpg
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Old 19th January 2003, 02:23 PM   #14
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Red face Ampzilla schematics

Hi Kevin,
I am sorry the link did not get through.
Just try
http://home.kimo.com.tw/skychutw/ampzilla/
and click on schematics of Ampzilla III for the balanced amplifier and on Son of Ampzilla for a simple example of a amplifier with PNP & NPN inputtransistors. I have downloaded your uberpages and have a look at it.
My first impression is your scheme is the same general picture as the Ampzilla III. Quite a achievement Kevin! Did you actually build the amplifier in the uberpages?
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Old 12th March 2004, 06:23 AM   #15
thanh is offline thanh  Viet Nam
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full complemetary amp,i built a amp like that.I use SLone's topo but i used resistor collector load instead of current mirror.I intend to build a amp which use X-topo
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Old 12th March 2004, 06:35 AM   #16
thanh is offline thanh  Viet Nam
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kevin!Where do DC adjust go?
bye!
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Old 12th March 2004, 11:51 PM   #17
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Folks, complementary symmetry is NOT perfect, because the comp. input devices are not perfectly matched, BUT look at the alternative. Single differential designs are OK on their input, BUT what about the drive for the second stage? Comp. Differential gives you almost perfect push-pull drive for the output stage. This criticism of the lack of perfect mirror image is lost in the advantage of one drive device turning on, while its complement is turning off from the opposite rail. This is invariably better as far as open loop distortion is concerned.
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Old 13th March 2004, 12:50 AM   #18
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I aggree, complementary symmetry is NOT perfect, because the comp. input devices are not perfectly matched.

However, Can I get my 2 cents in on part of the original question
"PNP" vs "NPN" ??

The origins of Transisitors, PNP was a very easy latice structure to acheive, the P doped portion then the N, then another P doped section, "Tada!" PNP, HOWEVER, NPN, ain't so easy to make (not then, and still is harder than pnp now) see, the bonding junction wants to be P biased, therefor the process we must use is WAY more complex to build an N bonding junction (Something to do with atomic latice or something) anyhow, so back in the beginnings PNP prevailed simply because they where a cheaper transistor to mass produce (VHS vs BETAMAX ???) since these where what everybody used back in those days, the progress continued on the prefection of the PNP junction, because NPN is needed in medical equipment (don't go there) the progress on manufacture of them has kept pace to a lesser degree, but NPN units rivial the cost of their PNP counterparts nowdays. but are still percived by "the old hands" in designing power sections, as being a "poor transistor" simply by design.

Some guys might say "P to N to P, that's the same as N to P to N ??? (NO it's not, as the N becomes the substrate, instead of P).
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Old 13th March 2004, 01:04 AM   #19
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Quote:
Originally posted by a31_ford
because NPN is needed in medical equipment (don't go there)

I am curious on this. Why would that be?
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Old 13th March 2004, 02:00 AM   #20
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Yes, in many cases, PNP transistors and N channel fets have an advantage. Why, because of the difference in mobility between holes and electrons. PNP has N in the base (sensitive region), and N channel fets use it for the channel. This is why, I am told. However, SOME NPN transistors have very high betas, better than pnps for the most part, and there must be some reason for this. The usual difference that can be easily measured between devices is the rbb' or intrinsic base resistivity. PNP's usually have about 1/2 the resistance compared to NPN's.
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