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Author Topic: Miscellaneous Technical Debates  (Read 49810 times)
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watts, I challenge you to show me any transistor data sheet that shows a "reversing threshold" and especially one that occurs "at certain frequencies".  If you are talking about the base-emitter junction "diode", it is likely that any circuit which repeatedly reverse-biased (base far more negative than emitter for an NPN) that diode until it conducted would just break the part.  Game over.  Your theory is wrong.

See the very last sentence here: http://en.wikipedia.org/wiki/Bipolar_junction_transistor#Vulnerabilities

Reverse breakdown of the B-E junction on a repeated basis just destroys the device and it is not a "certain frequencies" phenomena at all.
First of all, great pains were taken to assure that the circuitry Poynt is testing is exactly the very same one Lawrence tested.  Secondly, I challenge your assertion that varying the frequency of oscillation by a few "kz" would or could, in this circuit, reveal some magic "resonance" that would significantly change the COP.

It's just more silliness.  There are no hi-Q resonant circuits involved here.  Period.  Sorry...theories rejected.

Humbugger

Hum,

You can indeed have a reversed voltage on the base emitter of a transistor as long as the voltage and current is not outside the SOA of that transistor.

In some cases the reverse voltage is desired to fully switch off the transistor fast or to stop the low leakage current to flow from collector to emitter. A
bipolar transistor will not be broken if you design the reversed polarity voltage to be in accordance to the data sheet SOA for the transistor. Take the 2N2222
and the JT. This setup does not have any external protection diode from base to emitter. So the voltage will go each way in polarity from the trigger coil. But since
we have a current limiting resistor in series with the base and since the voltage is less than the break down voltage for the base emitter, then the transistor
will actually do fine.  So for a JT (without an external diode from base to emitter) the transistor will be repeatedly reverse-biased at each oscillation pulse
of the oscillator.

GL.
   
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Hum,

You can indeed have a reversed voltage on the base emitter of a transistor as long as the voltage and current is not outside the SOA of that transistor.
In some cases the reverse voltage is desired to fully switch off the transistor fast or to stop the low leakage current to flow from collector to emitter. A
bipolar transistor will not be broken if you design the reversed polarity voltage to be in accordance to the data sheet SOA for the transistor. Take the 2N2222
and the JT. This setup does not have any external protection diode from base to emitter. So the voltage will go each way in polarity from the trigger coil. But since
we have a current limiting resistor in series with the base and since the voltage is less than the break down voltage for the base emitter, then the transistor
will actually do fine.  So for a JT (without an external diode from base to emitter) the transistor will be repeatedly reverse-biased at each oscillation pulse
of the oscillator.

GL.

I am talking about reverse breakdown, not reverse bias.  Reverse breakdown is when the reverse B-E voltage exceeds the avalanche voltage of the B-E diode junction. Wattsup was implying that the transistor, at certain frequencies, was being driven into reverse breakdown and conducting current ...NOT just being reverse-biased.  There is a huge difference.  

Reverse bias is normal and, as you say, often used to speed up switching by depleting the junction faster.  Reverse breakdown, where the avalanche rating of the B-E junction is exceeded and reverse cconduction occurs will rather quickly destroy a small-signal transistor.

Also, the term SOA (Safe Operating Area) in the context of transistor data sheets is used only to describe the power-handling limits of the C-E or D-S path under forward bias and has little or nothing to do with reverse-bias or reverse breakdown rating of the B-E or G-S structure..

Humbugger
« Last Edit: 2011-02-13, 06:36:16 by humbugger »
   
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Well since when is OU research confined to a safe operating area?

Most of the circuits you have probably seen and worked with in your life work in a linear manner with no way of having energies reversing. They are surrounded by side circuits full of dampening devices and so on. Energy conservation is not your main criteria.

These devices can create harmonics that go way above the frequency ranges you know of. You have a damn transistor with an led across it. That LED is burning juice and creating harmonics that you do not even know about. You won't even see it if your scope is not in the right ranges.

So there is no need for your fat lip with me. I can do the same if you prefer.

My post was addressed to @ponty99 and I know WTF I am talking about. I see it on my bench every damn day so don't try to tell me this or that. Have you ever done something, then tried to replicate it and it does not work again. Ever wonder why? One small difference can make or break the effect ESPECIALLY AT THE mV LEVEL. So just sharpen your knife to slaughter your own rats and leave me alone. If those coils were not wound by a machine in a factory assembly line, then who can say one is identical to the other. GET IT?

wattsup


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Posts: 337
I am talking about reverse breakdown, not reverse bias.  Reverse breakdown is when the reverse B-E voltage exceeds the avalanche voltage of the B-E diode junction. Wattsup was implying that the transistor, at certain frequencies, was being driven into reverse breakdown and conducting current ...NOT just being reverse-biased.  There is a huge difference. 

Reverse bias is normal and, as you say, often used to speed up switching by depleting the junction faster.  Reverse breakdown, where the avalanche rating of the B-E junction is exceeded and reverse cconduction occurs will rather quickly destroy a small-signal transistor.

Also, the term SOA (Safe Operating Area) in the context of transistor data sheets is used only to describe the power-handling limits of the C-E path under forward bias and has nothing to do with reverse-bias or reverse breakdown rating of the B-E junction.

Humbugger

Hum,

No you where not.

Quote: "it is likely that any circuit which repeatedly reverse-biased (base far more negative than emitter for an NPN)"

GL.
   
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Wattsup:

Your theories are still both nonsense.  Do you not get that the same piece of hardware was tested by two different people?  There are not two different transformers here, only one.

You really get upset when your theories are popped, eh?  Sorry, but both of your proposed explanations are just plain wrong in this case.  Better luck next time.   :-*

Humbugger
   
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Hum,

No you where not.

Quote: "it is likely that any circuit which repeatedly reverse-biased (base far more negative than emitter for an NPN)"

GL.

Let's get the quote right please:

Quote
If you are talking about the base-emitter junction "diode", it is likely that any circuit which repeatedly reverse-biased (base far more negative than emitter for an NPN) that diode until it conducted would just break the part.

When you reverse bias until current is conducted you have achieved what?  REVERSE BREAKDOWN.  And why do they call it BREAKDOWN?

Humbugger
   
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Posts: 337
Let's get the quote right please:

When you reverse bias until current is conducted you have achieved what?  REVERSE BREAKDOWN.  And why do they call it BREAKDOWN?

Humbugger

Hum,

English is not my first language and I did miss that "conducting current" part, sorry, yes you are right, if you start to draw current
through a diode in the reversed direction it will certainly break, letting out that magic withe smoke. :-)

GL.
   
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Hum,

English is not my first language and I did miss that "conducting current" part, sorry, yes you are right, if you start to draw current
through a diode in the reversed direction it will certainly break, letting out that magic withe smoke. :-)

GL.

I knew it!  We are all just in a contest to see who gets to make POST #10,000  ;D
   
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Only two to go...
   
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10,000 posts!

Congratulations Poynt and Peter and all whoever runs this joint.  10,000 posts isn't much compared to some of the older forums thst have been around a while but it's the QUALITY of the posts that really counts!   O0

Humbugger
   
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I think Dumped is trying to intimate that he has one of these units on his bench exhibiting COP>1.

Looking forward to seeing your build and the awesome scope measurements of MEAN PI and PO Dumped.  O0

You're welcome.

.99

Oh...my mistake.  I apologize, Dumped.  I thought you were talking about tweaking the Lawrence unit that Poynt now has.  I didn't mean to come across so harsh...sorry.

Regarding below...most posts were moved here:  http://www.overunityresearch.com/index.php?topic=726.msg10699#msg10699

I think I may also owe Wattsup at least a conciliatory explanation if not an apology as well.  Milehigh's proposal that stored charge in the B-E diode could be causal of a 200ns spike as the transistor turns off is quite possible.  I guess I just objected to the way (the terms) you explained it.   The real name of this is simply "turn-off time" or, even more correctly, "reverse recovery time" and it has to do with minority carrier charges taking a brief time to be yanked out of the "just-previously-forward-conducting" B-E junction "diode".  All diodes exhibit this and "fast recovery" diodes including Schottky diodes are optimized for this.

The more current available to take the base negative (NPN) or to zero, the faster the reverse recovery will be.  200ns is a reasonable time, I'm guessing, in this circuit with the 2N2222.  It would depend on the base resistor a lot.

So...it's not really "frequency dependent" exactly and it's not actual breakdown either.  We were both kind of wrong, technically speaking, but I think we may have been talking about the same basic phenomena.  You and Milehigh might have converged on it had I not butted in so fiercely.  

I apologize for jumping on you so hard.  I'm a jerk and an asshole sometimes, in case you hadn't noticed.   :-[

Humbugger
« Last Edit: 2011-02-13, 05:47:08 by humbugger »
   
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Well since when is OU research confined to a safe operating area?
Most of the circuits you have probably seen and worked with in your life work in a linear manner with no way of having energies reversing. They are surrounded by side circuits full of dampening devices and so on. Energy conservation is not your main criteria.

First question answer;  Since OU research started using transistors and MOSFETs, unless you find that toasted ones work better  ???  

And I have worked with and designed many switching circuits and RF amplifiers of various classes that drive VHF/UHF frequency hot plasma loads inside precision-tuned optical-wavelength mirrored resonant chambers and have to deal hugely with forward and reverse energies as central critical features.  How in the world would you be in any position to speculate on what kind of circuits I've worked with, anyway?

Energy conservation and efficiency and low losses and reliability were always my main concerns in every power circuit I ever designed, sir.  Very rarely were any "side circuits" or "dampening devices" ever used except where the shit would hit the fan and toasted semiconductors would appear if certain "radiant events" were not held in check.  You see, my circuits had to actually do what they claimed!  Without breaking.  For years on end, every time.

Quote

These devices can create harmonics that go way above the frequency ranges you know of. You have a damn transistor with an led across it. That LED is burning juice and creating harmonics that you do not even know about. You won't even see it if your scope is not in the right ranges.

Well, if I don't know about them after 45 years of practical design and testing including RF and microwave stuff, just how would I learn?  From you?  Teach on, brother, teach on!  I'm all ears.

Quote

So there is no need for your fat lip with me. I can do the same if you prefer.

My post was addressed to @ponty99 and I know WTF I am talking about. I see it on my bench every damn day so don't try to tell me this or that. Have you ever done something, then tried to replicate it and it does not work again. Ever wonder why? One small difference can make or break the effect ESPECIALLY AT THE mV LEVEL. So just sharpen your knife to slaughter your own rats and leave me alone. If those coils were not wound by a machine in a factory assembly line, then who can say one is identical to the other. GET IT?

wattsup

I have always tried hard to spend enough time and effort studying my circuit designs and making sure the component sensitivities are reasonably low well before I physically build them.  When I first started out, there were lots of times things were fritzy and non-repeatable or just plain blew up.  Later, my designs generally tended to whip straight from the drawing board into full production without a glitch.  And they worked the same every time.  And they still work today.  After tens of thousands or even huindreds of thousands of copies put in the field being used daily all over the world.  Of course, I cheated.  I always knew precisely what I was trying to accomplish before I started fiddling on a design.  So I'm not as brave as you, okay?

Relax, there's no need for war or bitterness here.  I even apologized over in the original thread (it didn't get over here when the posts were moved).  I just think we misunderstood each other's terminology.  Chill, dude!  Peace out.

Humbugger
« Last Edit: 2011-02-13, 06:48:41 by humbugger »
   
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@milehigh

Quite playing your same violin, it is getting tiresome. I said exactly as it stands and no need for both you and @humchuck to give me your crap lessons. If you spend any time on OU research, you would not be talking like this so just try it on someone else.

Both you and @humchuck are a waste of time.

wattsup


---------------------------
   
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Wattsup:

If you are going to contribute to a given thread that other people are on then what you say may become part of the debate so deal with it.  Certainly there can be threads that you are on that I won't be on and I really won't care or be involved in what you say.  On threads where our paths cross you would not want to hear me rebut your points in detail.

An example Wattsup:

Quote
If those coils were not wound by a machine in a factory assembly line, then who can say one is identical to the other. GET IT?

You actually don't get it.  Who cares if the coils are wound by machine or wound by hand, it makes practically no difference at all.  They are basically identical if you ignore the very slight difference in inductance between a machine-wound and a hand wound coil, and that in itself is insignificant.  So perhaps you have some notion in your head about the "uniqueness" of a coil that you wound by hand and your thinking processes are like that for the work you do on your bench.  To me it smells of self-invention.  I can only speculate you have created your own belief system about how certain things work and some parts of your self-invented belief system are dead wrong.  I recall you making a comment during the Mylow affair about the specific arrangements of magnets on the various rotors that Mylow was demonstrating.  You said something like "With so many magnets, how do the magnetic fields produced by all the different magnets know where to go?"  WTF?  I was shocked when I read that, you have got to be kidding!

Saying myself and Humbugger are a waste of time is just sour grapes on your part.  Humbugger has 45 years worth of engineering experience in analog design in the real world.  That's absolutely awesome!

MileHigh
« Last Edit: 2011-02-14, 02:39:52 by MileHigh »
   

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...

Saying myself and Humbugger are a waste of time is just sour grapes on your part.  Humbugger has 45 years worth of engineering experience in analog design in the real world.  That's absolutely awesome!

MileHigh


Yes.  Awesome and commendable.

Hopefully this includes ample experience with the
"rats nest" enigma/paradox.



---------------------------
Treat everyone with kindness and respect. Not because they are nice, but because you are. - Unknown
   

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Well, if I don't know about them after 45 years of practical design and testing including RF and microwave stuff, just how would I learn?  From you?  Teach on, brother, teach on!  I'm all ears.


Humbugger, I thought you said you were Linda Damiani ?  Linda was said to be an undergraduate still studying Electrical Engineering in 2007 how would she (or you) be able to have 45 years of electrical design?  I don't get it are you Linda or not? or am I missing something? Private joke or something? Sorry if this is off topic, you can Pm me back if you want.


---------------------------
"Whatever our resources of primary energy may be in the future, we must, to be rational, obtain it without consumption of any material"  Nicola Tesla

"When bad men combine, the good must associate; else they will fall one by one, an unpitied sacrifice in a contemptible struggle."  Edmund Burke
   
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Linda Damiani was a pseudonym and fictitious person I invented after being banned at EF and OU.com.  the purpose was to get in afew choice last words.  Nothing more.  You see, I wasn't quite done calling Ashtweth's bluff on his lies.  I thought I thoroughly explained all that.   ;)

Humbugger
   
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I must agree with wattsup in this debate.

We have been using transistor junctions as zener diodes for decades in both discreet and integrated circuit design. There are product lines that have been developed that specifically take advantage of this phenomenon.

http://www.diodes.com/datasheets/ZTX415.pdf

http://en.wikipedia.org/wiki/Avalanche_transistor

http://www.freepatentsonline.com/3786443.html

But even some general purpose transistors can be used in this way. This really isn't new information and I am a bit surprised that some of our members here would debate the issue.  :P
   
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Harvey,

None of those references or applications have anything to do with reverse breakdown of the base-emitter junction, which is what the argument was about,,,sorry.

Humbugger

P.S.  I take it as a compliment and a reinforcement of my position when folks have to resort to "straw man" and "red herring" arguments against my position.  Changing what I said and arguing against that or inserting a completely different argument that has similar words in it but has nothing to do with the position I've taken seem to be the only hope of those who would argue against my position, so far.  But do keep trying...when I'm actually wrong, I'll admit it and thank you for correcting me  O0
« Last Edit: 2011-02-18, 13:13:28 by humbugger »
   
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From the post that opened this thread:
Quote from: humbugger
watts, I challenge you to show me any transistor data sheet that shows a "reversing threshold" and especially one that occurs "at certain frequencies".  If you are talking about the base-emitter junction "diode", it is likely that any circuit which repeatedly reverse-biased (base far more negative than emitter for an NPN) that diode until it conducted would just break the part.

The ZTX415 Datasheet provided clearly shows:
Current in Second Breakdown (Pulsed) 15A
with a "Reversing Threshold" (Emitter-Base Breakdown Voltage) V(BR)EBO 6 V IE=10mA
and Transition Frequency fT 40 MHz

It also boasts up to 60A Peak Avalanche current for 20ns

From the Wikipedia link I provided:


Notice the battery polarity in this configuration. Very clearly reversed biased or in your words quoted above "(base far more negative than emitter for an NPN)"

As the moderator of the technical debates I must declare Wattsup the winner in this debate.

Sorry humbugger, whether you accept it or not, you lose this one.  ;)


   
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Quote
watts, I challenge you to show me any transistor data sheet that shows a "reversing threshold" and especially one that occurs "at certain frequencies".  If you are talking about the base-emitter junction "diode", it is likely that any circuit which repeatedly reverse-biased (base far more negative than emitter for an NPN) that diode until it conducted would just break the part.

From the post that opened this thread:
The ZTX415 Datasheet provided clearly shows:
Current in Second Breakdown (Pulsed) 15A
with a "Reversing Threshold" (Emitter-Base Breakdown Voltage) V(BR)EBO 6 V IE=10mA
and Transition Frequency fT 40 MHz

It also boasts up to 60A Peak Avalanche current for 20ns

From the Wikipedia link I provided:


Notice the battery polarity in this configuration. Very clearly reversed biased or in your words quoted above "(base far more negative than emitter for an NPN)"

As the moderator of the technical debates I must declare Wattsup the winner in this debate.

Sorry humbugger, whether you accept it or not, you lose this one.  ;)




Your valiant attempts to nurse Wattsup's bruised ego are commendable, however misguided.  I do not see any reference to the bogus term "reversing threshold" in any of your references.  The Ft (transition frequency) specification and the reverse breakdown voltage for B-E junction are entirley unrelated and appear on every transistor data sheet.  Citing a diagram showing a reverse-biased transistor is not a proof that pounding a B-E junction repeatedly into reverse breakdown will not have a destructive effect, as was my point.  Note that the reverse breakdown is rated at 10 micro-amps, not 10mA as you state.  The reason is simple: If the current into the reversed B-E junction is not limited to a very low level, the junction is destroyed.  Poof!

More straw men fishing for red herrings... ;)  All you have proven is that you don't understand the specifications on transistor data sheets or how they relate (or don't relate) to each other.  Try it!  Get yourself one of those avalanche transistors and pound the B-E junction with 10mA reverse-bias beyond the breakdown voltage pulses repeatedly.  Then come back and tell me what happened.

Humbugger

P.S.  Regarding your quoting me about reverse bias, that little snippet, taken out of context and misrepresented is the classic example of a fallacious straw man argument.  Not only that, but the exact same misquote had been discussed and addressed in this thread when another poster tried the same straw-man argument.

See here: http://www.overunityresearch.com/index.php?topic=726.msg10709#msg10709
« Last Edit: 2011-02-18, 12:52:25 by humbugger »
   
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Furthermore...Harvey,

Here is the Zetex application note for the avalanche transistor you use to prove your and Wattsup's ABSOLUTELY WRONG and PATENTLY SILLY argument that running the B-E junction repeatedly into reverse breakdown with heavy current flow is perfectly normal and done all the time.  Read the app note carefully.  Look at the diagrams.  In no instance is reverse breakdown (or even reverse bias) of the B-E junction ever mentioned, recommended, shown or discussed.  All of the avalanching they are talking about occurs in the C-E path.  Why do you suppose that is?

IT'S BECAUSE THE OPERATION OF THESE TRANSISTORS HAS NOTHING TO DO WITH REVERSE BREAKDOWN OF THE B-E JUNCTION, A CONDITION THAT IS CLEARLY AND ALWAYS AVOIDED IN ALL TRANSISTOR APPLICATIONS with the possible exception of using the B-E reverse breakdown avalanche as a noise source at extremely low micro-amp DC currents.  Show us an app note or a transistor data sheet that encourages reverse-breakdown operation of any bipolar transistor BASE-EMITTER JUNCTION before you go off half-cocked and start awarding prizes for winning debates, PLEASE!

http://www.diodes.com/_files/products_appnote_pdfs/zetex/an8.pdf

Humbugger
« Last Edit: 2011-02-18, 13:12:34 by humbugger »
   

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It's not as complicated as it may seem...
Harvey,

The breakdown occurs in the B-C junction, not the B-E junction.

VBB is implemented only to bias the B-C junction that much closer to breakdown. It just so happens that the B-E junction remains reversed-biased (not the same as avalanched) in this mode of operation, until avalanche occurs, when it then becomes rapidly forward-biased.

On that basis, and on what the debate is apparently about, you may want to reconsider your position.

.99
   
Group: Guest
When debating, it is not fair nor productive to misrepresent the opponent's position and then argue against your own misrepresentation.  You guys are arguing against me as if I had said:

1.  You can never put a reverse bias voltage on a transistor base without blowing it up. OR
2.  No circuit reliably uses the avalanche effect OR
3.  The words "frequency" and "breakdown" and "avalanche" can never appear on the same transistor data sheet OR
4.  Some other unrelated incorrect nonsense.

The specific arguments are, as I understand them:

Wattsup's position is that driving a transistor's base into reverse breakdown without extreme measures to limit the current is perfectly fine, non-destructive and is a mode used all the time in commonly-known circuits.  Furthermore, he states that the reverse breakdown Base-Emitter characteristics are frequency dependent.  He coins the term "reversing threshold" as being this frequency dependent and quite useful trait of operating transistor Base-Emitter junctions in the reverse-breakdown mode..

My position is that none of those assertions are true or valid.  My position is that the reverse breakdown rating of a transistor B-E junction is not frequency dependant and also that repeatedly forcing B-E junctions into reverse breakdown wherein reverse current flows will degade or destroy the transistor unless the current is externally limited to a very low level.

Thus far, I have seen nor heard any evidence or argument that supports Wattsup's position nor any that tends to disprove my position.  The straw-man arguments being posed multiple times, in fact, tends to indicate that there is no valid argument against my position.

Humbugger
   
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