bipolar (bjt) transistor families for audio power output stages
 User Name Stay logged in? Password
 Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read Search

 Solid State Talk all about solid state amplification.

 Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Bigun
diyAudio Member

Join Date: Jan 2009
Location: Waterloo, ON or Herefordshire
Quote:
 Originally Posted by Lumba Ogir I use feedback and it punishes me mercilessly too,
your pain explains the strange posts of yours
__________________
"The test of the machine is the satisfaction it gives you. There isn't any other test. If the machine produces tranquility it's right. If it disturbs you it's wrong until either the machine or your mind is changed." Robert M Pirsig.

Piercarlo
diyAudio Member

Join Date: Nov 2006
Quote:
 Originally Posted by tiefbassuebertr Lumba has to do professionally with "Heisenberg uncertainty principle"?
No he has quite to do with Sokal's mock. As mocked of course.

Piercarlo

Lumba Ogir
Banned

Join Date: Apr 2005
Location: Stockholm
SQLGuy,
Quote:
 This is another ridiculous statement. Heisenberg uncertainty and Planck values describe the minimum of what can be measured in the universe. Period.
It would be exceedingly distressing to use a period denoting full stop after that confused statement. More relevantly, it states that two variables cannot be calculated simultaneously (anywhere in the universe). What to expect from an analysis where linearity and time are mathematical constants and highly influential parameters have ideal values?

 13th January 2010, 10:01 AM #684 traderbam   diyAudio Member     Join Date: Jan 2002 Location: Earth Quiz: Which is faster? a) BJT with fT=10MHz and beta=100 b) BJT with fT=10MHz and beta=10 __________________ “Simplicity is the ultimate sophistication.” Leonardo da Vinci
Claude Abraham
diyAudio Member

Join Date: Apr 2003
Location: NE Ohio
Quote:
 Originally Posted by traderbam Quiz: Which is faster? a) BJT with fT=10MHz and beta=100 b) BJT with fT=10MHz and beta=10
I choose b), and that's my final answer.
__________________
"We wish to reach the moon, not because it is easy, but because it is hard."
John F. Kennedy, 1917-1963, US President

orjan
diyAudio Member

Join Date: Mar 2005
Location: Stockholm
Quote:
 Originally Posted by Lumba Ogir SQLGuy, linearity and time are mathematical constants
Could you explain a bit more about time and linearity being a constants.

/örjan

megajocke
diyAudio Member

Join Date: Jan 2003
Quote:
 Originally Posted by traderbam Quiz: Which is faster? a) BJT with fT=10MHz and beta=100 b) BJT with fT=10MHz and beta=10
None. Both lack proper propulsion means so they will be having a hard time getting any speed whatsovever.

Seriously, "faster" isn't well defined enough to make much sense. The beta=10 sure has a higher turnover frequency, but the beta=100 has higer or equal current gain at all frequencies. It depends on the application.

 13th January 2010, 01:11 PM #688 Lumba Ogir   Banned   Join Date: Apr 2005 Location: Stockholm Howdy, funny question. Which is higher 10MHz or 10MHz?
SQLGuy
diyAudio Member

Join Date: Jan 2009
Quote:
 Originally Posted by Lumba Ogir SQLGuy, It would be exceedingly distressing to use a period denoting full stop after that confused statement. More relevantly, it states that two variables cannot be calculated simultaneously (anywhere in the universe). What to expect from an analysis where linearity and time are mathematical constants and highly influential parameters have ideal values?
Sorry. It's called emphasis. It's something we do in English. I didn't realize it would be confusing.

You misunderstand what Heisenberg's principle says. It says that, due to the effects of measurement, e.g. the bombardment of electrons that it would take to illuminate and measure the position of a particle, the very act of measurement disturbs the item being measured. More specifically, it states that you cannot know with pefect precision BOTH the position and velocity of a very small particle. You can know one or the other, but not both. As you increase the precision of one measurement, you reduce the precision of the other.

However, this principle doesn't just define the limits of what can be measured; as far a current modern physics can tell, it defines the limits of what actually exists. In other words, unobserved quantum particles, like electrons, are not point objects, but smears of probability. When observed, the electron will collapse to some point within the space defined by the Schroedinger probability equation. It will probably show up at the point of highest probability, but it could show up anywhere within the "smear." This is how tunneling works. In a tunnel diode, for instance, there is an insulating layer through which electrons cannot pass; but, since the probability fields of the electrons extend beyond this barrier (probability field shapes are not at all influenced by external objects or pressures), some electrons will appear on the other side of the barrier.

The biggest thing to keep in mind, and that I think you are missing, is that this all applies only to VERY SMALL things or VERY SHORT periods of time. Planck discovered and calculated the applications of Heisenberg's principle to define the minimums of things that could be measured. A Planck length, for example, the minimum length that can be measured, is 1.616252×10−35 meters.

Please explain, now, how any of this is going to affect any of LTSpice's very macro analyses.

Thanks,
Paul

Last edited by SQLGuy; 13th January 2010 at 01:52 PM. Reason: typo

syn08
Account disabled at member's request

Join Date: Aug 2005
Location: Toronto
Quote:
 Originally Posted by traderbam Quiz: Which is faster? a) BJT with fT=10MHz and beta=100 b) BJT with fT=10MHz and beta=10
If that helps, alpha=1-Tr/Tn where Tr is the transit time through the base and Tn is the minority carrier lifetime in the quasineutral base. Recall beta = alpha/(1-alpha) and, of course, low Tr means high Ft.

Now you draw the conclusion. Whatever that is, I'll tell you in advance it's wrong for at least two good reasons:

- The base concentration grading is essential for defining Tr. As such, this is way more important than the simple Tr to alpha relationship, and can easily reverse the conclusion.

- While Ft is a small signal related number, where the device models are already linearized, "speed" is usually related to the large signal model where the nonlinear charge injection and transport mechanisms are dominant.

Comparing Ft with the "speed" and correlating to beta is at best as correct as comparing small signal and large signal slew rates in an amp. A relationship may exist, but it doesn't always hold for all topologies and is ultimately largely irrelevant.

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is Off Forum Rules
 Forum Jump User Control Panel Private Messages Subscriptions Who's Online Search Forums Forums Home Site     Site Announcements     Forum Problems Amplifiers     Solid State     Pass Labs     Tubes / Valves     Chip Amps     Class D     Power Supplies     Headphone Systems Source & Line     Analogue Source     Analog Line Level     Digital Source     Digital Line Level     PC Based Loudspeakers     Multi-Way     Full Range     Subwoofers     Planars & Exotics Live Sound     PA Systems     Instruments and Amps Design & Build     Parts     Equipment & Tools     Construction Tips     Software Tools General Interest     Car Audio     diyAudio.com Articles     Music     Everything Else Member Areas     Introductions     The Lounge     Clubs & Events     In Memoriam The Moving Image Commercial Sector     Swap Meet     Group Buys     The diyAudio Store     Vendor Forums         Vendor's Bazaar         Sonic Craft         Apex Jr         Audio Sector         Acoustic Fun         Chipamp         DIY HiFi Supply         Elekit         Elektor         Mains Cables R Us         Parts Connexion         Planet 10 hifi         Quanghao Audio Design         Siliconray Online Electronics Store         Tubelab     Manufacturers         AKSA         Audio Poutine         Musicaltech         Aussie Amplifiers         CSS         exaDevices         Feastrex         GedLee         Head 'n' HiFi - Walter         Heatsink USA         miniDSP         SITO Audio         Twin Audio         Twisted Pear         Wild Burro Audio

 Similar Threads Thread Thread Starter Forum Replies Last Post nigelwright7557 Solid State 11 26th May 2008 01:55 PM aldovan Solid State 7 31st August 2007 01:31 PM mtlin12 Solid State 5 1st April 2005 06:55 AM hienrich Solid State 3 26th December 2004 07:18 AM

 New To Site? Need Help?

All times are GMT. The time now is 04:58 PM.