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Various Transistors Tested for Ic and Vce(sat)

In article , snipped-for-privacy@invalid.invalid mentioned...

As for a hacker, I seriously hope so. After seeing what you guys are saying in the other Spice thread, better you than me.

Forced beta? As I said in the other followup, as the transistor goes into saturation, the base to collector junction becomes forward biased, and the beta is reduced as more of the base current gets diverted to the collector.

Revert to fundamentals? Well, what am I doing above when I put pencil to paper? Isn't that fundamentals? Seriously! Guessing at what?

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Watson A.Name - "Watt Sun, Dar
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In article , snipped-for-privacy@invalid.invalid mentioned...

For what current? There has to be some limit to the current, like a load resistor, or the transistor will 'let the smoke out' as some hav fondly put it.

Congrats! I'm patting myself on the back. I put my hand on the copy machine, made a copy, thumbtacked it to the wall, and now I can lean up against it!

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Watson A.Name - "Watt Sun, Dar

In article , snipped-for-privacy@invalid.invalid mentioned...

"the 2N3904 has a lower beta than the ZTX651" at a given current. I assume that at some small current, maybe less than a mA, the ZTX651 has lower beta than the 2N3904. IIRC the data sheets use beta holdup. I assume that this term is used to mean that the beta doesn't drop off as quickly as current increases. But the beta tends to peak at some optimum point depending on the transistor.

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Reply to
Watson A.Name - "Watt Sun, Dar

[snip]

The ZTX651 has slower drop in beta versus current since it is physically larger and less subject to current crowding out to the edge of the emitter.

You would expect that the ZTX651 beta *would* be lower than the 2N3904 at low currents, but the model says no.

Since this fall-off at low currents is leakage-related, I would guess that the ZTX651 has a higher voltage rating? (I don't have a data sheet available.)

...Jim Thompson

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|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
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Reply to
Jim Thompson

Current crowding causes beta to fall, so there often is a limit before "smoke".

LOL!

...Jim Thompson

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|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
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Reply to
Jim Thompson

And thank you very much for that.

Unfortunately, when people don't understand what I do, they seem less willing to pay for it!

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Reply to
John Todd

Customers don't need to understand "why", just that it works and passes worst-case analysis.

...Jim Thompson

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|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.
Reply to
Jim Thompson

[snip]

H'mm. My experience is the same a John Todd's. You HAVE to give an explanation. It may be that it doesn't apply to the insides of ICs; they may be deemed 'magic'.

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John Woodgate

Yep, Particularly when I tell 'em it's all done with mirrors ;-)

...Jim Thompson

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|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.
Reply to
Jim Thompson

In article , snipped-for-privacy@invalid.invalid mentioned...

All the BC338s I've measured for beta have betas of typically 300 to

400, and at least 240. So if they were used in your example chart, the blue line would be at the very top, or off the chart.

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My email address is whitelisted. *All* email sent to it goes directly to the trash unless you add NOSPAM in the Subject: line with other stuff. alondra101 hotmail.com Don't be ripped off by the big book dealers. Go to the URL that will give you a choice and save you money(up to half).
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You'll be glad you did! Just when you thought you had all this figured out, the gov't changed it:
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Reply to
Watson A.Name - "Watt Sun, Dar

On Wed, 07 Jan 2004 08:44:06 -0700, the highly esteemed Jim Thompson enlightened us with these pearls of wisdom:

Allow me:

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Greg Pierce

In article , snipped-for-privacy@invalid.invalid mentioned...

Using the National die specs as a reference, the 2N3904 has a die size of 13 by 13 mils, or 169 square mils. In contrast, the 2N4401 has a die of 18 by 18 mils or a 324 square mils, almost double the area. So it seems that size does matter.

The model? Does Zetex publish this, or is it something from a supposedly "authoritative source"? But then why should I care, since I'm using the real thing, not tne model.

Seems that the more-than-1A transistors usually have a low Vceo, but the ZTX651 is not as low as the others.

Data sheet at

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and take the lame reverse Turing Test, etc.

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###Got a Question about ELECTRONICS?   Check HERE First:###
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My email address is whitelisted.  *All* email sent to it 
goes directly to the trash unless you add NOSPAM in the 
Subject: line with other stuff.  alondra101  hotmail.com
Don't be ripped off by the big book dealers.  Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com  You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
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Watson A.Name - "Watt Sun, Dar

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