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nuckollsr(at)cox.net
Guest

Posted: Thu Oct 26, 2006 6:16 pm Post subject: "Electronics" is 100 years old this year

One of my favorite fun reads in the business is "Nuts and Volts"

magazine:



http://www.nutsvolts.com/



The latest issue features an article about the birth of the

triode vacuum tube where for the first time, a relatively

unspectacular control of electrons crossing the evacuated space

between cathode and anode enclosed in a vacuum was accomplished.



The device had GAIN. This meant it could amplify and oscillate.

Radio, long distance telephones and talking movies would rise

quickly to great heights on this invention that also planted seeds

for the amazing feats of function and miniaturization that we

enjoy today.



Every week I get journals in the mail that speak of whizzy new

devices cast in silicon . . . Unfortunately, we're so busy

certifying airplanes these days, we don't have time to engineer

them any more.



I have hopes of rectifying that where I work but the odds are

long and the time ever shorter. In the mean time, the things you

folks are building, buying and incorporating into your airplanes has

become the leading edge of the future. There's no stigma

associated with calling ones self "amateur" . . . obviously

EVERY new idea was conceived and promulgated by amateurs.



Anyone interested in a little light reading and a short trip

back in time is encouraged to peek at a series of historical

images at:



http://www.cedmagic.com/history/deforest-audion.html



also:



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



http://mixonline.com/TECnology-Hall-of-Fame/leedeforest-triode-vacuum-090106/



http://chem.ch.huji.ac.il/~eugeniik/history/deforest.htm



http://www.ee.umd.edu/~taylor/Electrons3.htm



        Bob . . .

      ---------------------------------------------------------

      < What is so wonderful about scientific truth...is that >

      < the authority which determines whether there can be   >

      < debate or not does not reside in some fraternity of   >

      < scientists; nor is it divine. The authority rests     >

      < with experiment.                                      >

      <                            --Lawrence M. Krauss       >

      ---------------------------------------------------------

sportav8r(at)gmail.com
Guest

Posted: Thu Oct 26, 2006 7:02 pm Post subject: "Electronics" is 100 years old this year

 	  Quote: 	
		  From the Mixonline link:


	


 	  Quote: 	
		  >In this case, a fairly minute signal (voltage) at the grid would

result in huge changes in the plate voltage, and the first
	


amplification device was born.<<



Um, that would be huge changes in the plate _current_, wouldn't it?

Voltage doesn't sag much with a well-regulated plate supply.



Voltage changes occur across the plate _load R_, true...



Be careful what you read on the 'net, right?



-Bill B



<should get my Hyundai and the old alternator back tomorrow>



On 10/26/06, Robert L. Nuckolls, III <nuckollsr(at)cox.net> wrote:

 	  Quote: 	
		   



 One of my favorite fun reads in the business is "Nuts and Volts"

 magazine:



 http://www.nutsvolts.com/



 The latest issue features an article about the birth of the

 triode vacuum tube where for the first time, a relatively

 unspectacular control of electrons crossing the evacuated space

 between cathode and anode enclosed in a vacuum was accomplished.



 The device had GAIN. This meant it could amplify and oscillate.

 Radio, long distance telephones and talking movies would rise

 quickly to great heights on this invention that also planted seeds

 for the amazing feats of function and miniaturization that we

 enjoy today.



 Every week I get journals in the mail that speak of whizzy new

 devices cast in silicon . . . Unfortunately, we're so busy

 certifying airplanes these days, we don't have time to engineer

 them any more.



 I have hopes of rectifying that where I work but the odds are

 long and the time ever shorter. In the mean time, the things you

 folks are building, buying and incorporating into your airplanes has

 become the leading edge of the future. There's no stigma

 associated with calling ones self "amateur" . . . obviously

 EVERY new idea was conceived and promulgated by amateurs.



 Anyone interested in a little light reading and a short trip

 back in time is encouraged to peek at a series of historical

 images at:



 http://www.cedmagic.com/history/deforest-audion.html



 also:



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



 http://mixonline.com/TECnology-Hall-of-Fame/leedeforest-triode-vacuum-090106/



 http://chem.ch.huji.ac.il/~eugeniik/history/deforest.htm



 http://www.ee.umd.edu/~taylor/Electrons3.htm



         Bob . . .

       ---------------------------------------------------------

       < What is so wonderful about scientific truth...is that >

       < the authority which determines whether there can be   >

       < debate or not does not reside in some fraternity of   >

       < scientists; nor is it divine. The authority rests     >

       < with experiment.                                      >

       <                            --Lawrence M. Krauss       >

       ---------------------------------------------------------

bob(at)bob-white.com
Guest

Posted: Thu Oct 26, 2006 8:02 pm Post subject: "Electronics" is 100 years old this year

Hi Bill,



The description is OK.  Increased current thru the vacuum tube causes

an increased voltage drop across the plate load.  Plate voltage is the

supply voltage minus the load resistor voltage, so an increased current

results in a reduced plate voltage and vice versa.



Bob W.

On Thu, 26 Oct 2006 23:01:22 -0400

"Bill Boyd" <sportav8r(at)gmail.com> wrote:



 	  Quote: 	
		   

 

 >From the Mixonline link:

 

 >>In this case, a fairly minute signal (voltage) at the grid would

 result in huge changes in the plate voltage, and the first

 amplification device was born.<<

 

 Um, that would be huge changes in the plate _current_, wouldn't it?

 Voltage doesn't sag much with a well-regulated plate supply.

 

 Voltage changes occur across the plate _load R_, true...

 

 Be careful what you read on the 'net, right?

 

 -Bill B

 

 <should get my Hyundai and the old alternator back tomorrow>

 

 On 10/26/06, Robert L. Nuckolls, III <nuckollsr(at)cox.net> wrote:

 > 

 >

 > One of my favorite fun reads in the business is "Nuts and Volts"

 > magazine:

 >

 > http://www.nutsvolts.com/

 >

 > The latest issue features an article about the birth of the

 > triode vacuum tube where for the first time, a relatively

 > unspectacular control of electrons crossing the evacuated space

 > between cathode and anode enclosed in a vacuum was accomplished.

 >

 > The device had GAIN. This meant it could amplify and oscillate.

 > Radio, long distance telephones and talking movies would rise

 > quickly to great heights on this invention that also planted seeds

 > for the amazing feats of function and miniaturization that we

 > enjoy today.

 >

 > Every week I get journals in the mail that speak of whizzy new

 > devices cast in silicon . . . Unfortunately, we're so busy

 > certifying airplanes these days, we don't have time to engineer

 > them any more.

 >

 > I have hopes of rectifying that where I work but the odds are

 > long and the time ever shorter. In the mean time, the things you

 > folks are building, buying and incorporating into your airplanes has

 > become the leading edge of the future. There's no stigma

 > associated with calling ones self "amateur" . . . obviously

 > EVERY new idea was conceived and promulgated by amateurs.

 >

 > Anyone interested in a little light reading and a short trip

 > back in time is encouraged to peek at a series of historical

 > images at:

 >

 > http://www.cedmagic.com/history/deforest-audion.html

 >

 > also:

 >

 > http://en.wikipedia.org/wiki/Vacuum_tube

 >

 > http://mixonline.com/TECnology-Hall-of-Fame/leedeforest-triode-vacuum-090106/

 >

 > http://chem.ch.huji.ac.il/~eugeniik/history/deforest.htm

 >

 > http://www.ee.umd.edu/~taylor/Electrons3.htm

 >

 >

 >

 >

 >

 >         Bob . . .

 >

 >

 >       ---------------------------------------------------------

 >       < What is so wonderful about scientific truth...is that >

 >       < the authority which determines whether there can be   >

 >       < debate or not does not reside in some fraternity of   >

 >       < scientists; nor is it divine. The authority rests     >

 >       < with experiment.                                      >

 >       <                            --Lawrence M. Krauss       >

 >       ---------------------------------------------------------

 >

 >

 >

 >

 >

 >

 

 

 

 


	




-- 

N93BD - Rotary Powered BD-4 - http://www.bob-white.com

First engine start 1/7/06 - Special Airworthiness Certificate 10/1/06

Cables for your rotary installation - http://www.roblinphoto.com/shop/

Jim Baker

Joined: 30 Mar 2006
Posts: 181
Location: Sayre, PA

Posted: Thu Oct 26, 2006 8:15 pm Post subject: "Electronics" is 100 years old this year

 	  Quote: 	
		   http://chem.ch.huji.ac.il/~eugeniik/history/deforest.htm


	


This is in no way intended to demean or diminish De Forest's 

accomplishments, however......



"To place a man in a multi-stage rocket and project him into the 

controlling gravitational field of the moon.... I am bold enough to 

say that such a man-made voyage will never occur regardless of 

all future advances."



- Dr. Lee De Forest, famous engineer, 1957



I would add that perhaps one should stick to topics they know 

well. Dr. De Forest obviously understood the electron's basic 

uses far better than he did the future use of those same 

"particles" and the devices they would spawn, enabling the very 

thing he predicted would not happen to become possible.  It's 

always a point of some amazement to me just how limited a 

capacity most people have in understanding what the future 

holds. As for me, I wish I knew something......anything......

Jim Baker

580.788.2779

Elmore City, OK

N6030X(at)DaveMorris.com
Guest

Posted: Thu Oct 26, 2006 8:41 pm Post subject: "Electronics" is 100 years old this year

Yeah, and Bill Gates once said "640K will be enough for ANY program".



Dave Morris

At 11:14 PM 10/26/2006, you wrote:

 	  Quote: 	
		  



 > http://chem.ch.huji.ac.il/~eugeniik/history/deforest.htm



This is in no way intended to demean or diminish De Forest's

accomplishments, however......



"To place a man in a multi-stage rocket and project him into the

controlling gravitational field of the moon.... I am bold enough to

say that such a man-made voyage will never occur regardless of

all future advances."



- Dr. Lee De Forest, famous engineer, 1957



I would add that perhaps one should stick to topics they know

well. Dr. De Forest obviously understood the electron's basic

uses far better than he did the future use of those same

"particles" and the devices they would spawn, enabling the very

thing he predicted would not happen to become possible.  It's

always a point of some amazement to me just how limited a

capacity most people have in understanding what the future

holds. As for me, I wish I knew something......anything......

Jim Baker

580.788.2779

Elmore City, OK

nuckollsr(at)cox.net
Guest

Posted: Fri Oct 27, 2006 5:22 am Post subject: "Electronics" is 100 years old this year

At 11:01 PM 10/26/2006 -0400, you wrote:



 	  Quote: 	
		  



 From the Mixonline link:



>>In this case, a fairly minute signal (voltage) at the grid would

result in huge changes in the plate voltage, and the first

amplification device was born.<<



Um, that would be huge changes in the plate _current_, wouldn't it?

Voltage doesn't sag much with a well-regulated plate supply.


	


    Yes . . . let's hope the writer stuck that in to see

    if you were really reading and understanding the

    words and the physics they described . . .

 	  Quote: 	
		  Voltage changes occur across the plate _load R_, true...



Be careful what you read on the 'net, right?


	


    EVERYTHING ANYONE WRITES is fair game for critical

    review. Mistakes of gross error and misunderstanding

    happen all the time. I think I've offered here on

    the List, my own perceptions and appreciation for

    standing at the front of the room in a good critical

    review. It's win-win: either my design and ideas are

    validated . . . or a bad idea is prevented from going

    to production.



    I'm working on a white paper for my managers that

    describes the functional IR&D effort. Too many folks

    with decision making responsibility view the IR&D

    FACILITY as a collection of plant, tools, inventory,

    and a budget . . . they're really proud of an air-

    conditioned, well lit room full of shiny tools and

    bins full of parts. I'm attempting to help them understand

    that real IR&D happens in a community of individuals

    who INHABIT such a facility. It's a cross-fertilization

    of ideas filtered though the skills and understanding

    of several individuals that makes the magic of IR&D

    really happen. The facility is useful (and can even

    be tracked on the balance sheet), but the real value

    resides in an intangible collection of skill and a

    willingness of individuals to use it that makes the

    IR&D effort live or die. There's an audio track I'll

    invite you to listen to at:



http://www.aeroelectric.com/Temp/Virgil_Elings-Look_at_the_Big_Picture.mp3



    I would LOVE to work for and with this guy. When it

    comes to getting past the BS and doing real science

    that leads to useful production, he's "da man!".



    We're all doing IR&D here. The 'net is a huge resource

    of data, a great deal of which is intended to entertain

    or convince you to buy something. And yes, even attempts

    at good teaching will have errors. But it's the

    COMMUNITY of researchers here on the List that provides

    the necessary filtering and perspective to discover

    simple-ideas for assembly into new inventions based on

    a common understanding.



    Bill, you get the gold star for the day in catching

    the writer's error and bringing it to the attention

    of interested individuals. Good catch!



    Bob . . .

nuckollsr(at)cox.net
Guest

Posted: Fri Oct 27, 2006 5:40 am Post subject: "Electronics" is 100 years old this year

At 11:14 PM 10/26/2006 -0500, you wrote:



 	  Quote: 	
		  



 > http://chem.ch.huji.ac.il/~eugeniik/history/deforest.htm



This is in no way intended to demean or diminish De Forest's

accomplishments, however......



"To place a man in a multi-stage rocket and project him into the

controlling gravitational field of the moon.... I am bold enough to

say that such a man-made voyage will never occur regardless of

all future advances."



- Dr. Lee De Forest, famous engineer, 1957



I would add that perhaps one should stick to topics they know

well. Dr. De Forest obviously understood the electron's basic

uses far better than he did the future use of those same

"particles" and the devices they would spawn, enabling the very

thing he predicted would not happen to become possible.  It's

always a point of some amazement to me just how limited a

capacity most people have in understanding what the future

holds. As for me, I wish I knew something......anything......


	


    Your observation serves to illustrate one of the

    points in my IR&D White Paper. The most talented

    among us are still subject to the foibles of the

    human condition. Another example:



"In science there is only physics; all the rest is stamp collecting."



[If a ball, say of water or glass] "as large as a football, were

to be magnified up to the size of the earth, each constituent

molecule being magnified in the same proportion, the magnified

structure would be more coarse-grained than a heap of shot, but

probably less coarse-grained than a heap of footballs."



and



"If you can not measure it, you can not improve it."



    These ideas were offered by Lord Kelvin in the late

    1800's. He made huge contributions to the understanding

    of physics. But the same individual was observed to

    say,



"X-rays will prove to be a hoax."



"Wireless [telegraphy] is all very well but I'd rather send

a message by a boy on a pony!"



"Radio has no future."



and when Writing to Niagara Falls Power Company he said,

"Trust you will avoid the gigantic mistake of alternating current."



    As a society we are too willing to brush aside

    the talents and contributions of very willing and

    able individuals based on some past transgression

    or ill-conceived utterance. But then, few in society

    have understanding or ability to participate in

    an "IR&D community". Were it not for those few

    individuals in our history, we would not be

    convening here on this List to discover and share

    better ways to build airplanes . . . indeed, there would

    be no Internet upon which we might convene anything.



    Bob . . .

bob(at)bob-white.com
Guest

Posted: Fri Oct 27, 2006 6:22 am Post subject: "Electronics" is 100 years old this year

On Fri, 27 Oct 2006 08:21:46 -0500

"Robert L. Nuckolls, III" <nuckollsr(at)cox.net> wrote:



 	  Quote: 	
		   

 

 At 11:01 PM 10/26/2006 -0400, you wrote:

 

 >

 >

 > From the Mixonline link:

 >

 >>>In this case, a fairly minute signal (voltage) at the grid would

 >result in huge changes in the plate voltage, and the first

 >amplification device was born.<<

 >

 >Um, that would be huge changes in the plate _current_, wouldn't it?

 >Voltage doesn't sag much with a well-regulated plate supply.

 

     Yes . . . let's hope the writer stuck that in to see

     if you were really reading and understanding the

     words and the physics they described . . .

 

 

 >Voltage changes occur across the plate _load R_, true...

 >

 >Be careful what you read on the 'net, right?

 

     EVERYTHING ANYONE WRITES is fair game for critical

     review. Mistakes of gross error and misunderstanding

     happen all the time. I think I've offered here on

     the List, my own perceptions and appreciation for

     standing at the front of the room in a good critical

     review. It's win-win: either my design and ideas are

     validated . . . or a bad idea is prevented from going

     to production.

 

<snip>
	




 	  Quote: 	
		   

     Bill, you get the gold star for the day in catching

     the writer's error and bringing it to the attention

     of interested individuals. Good catch!

 

     Bob . . .

 

 

I think you guys are mixing up plate supply with plate voltage.  The
	


load resistor is between the supply and the plate.  When the current

increases, the voltage across the load resistor increases. Therefore

the plate voltage goes down.  There isn't anything wrong with the

original description.



Bob W.



-- 

N93BD - Rotary Powered BD-4 - http://www.bob-white.com

First engine start 1/7/06 - Special Airworthiness Certificate 10/1/06

Cables for your rotary installation - http://www.roblinphoto.com/shop/

nuckollsr(at)cox.net
Guest

Posted: Mon Oct 30, 2006 7:52 am Post subject: "Electronics" is 100 years old this year

At 08:21 AM 10/27/2006 -0600, you wrote:

 	  Quote: 	

 >

 >     Bill, you get the gold star for the day in catching

 >     the writer's error and bringing it to the attention

 >     of interested individuals. Good catch!

 >

 >     Bob . . .

 >

 >

I think you guys are mixing up plate supply with plate voltage.  The

load resistor is between the supply and the plate.  When the current

increases, the voltage across the load resistor increases. Therefore

the plate voltage goes down.  There isn't anything wrong with the

original description.

    Good for you sir. Bill, bend over. I'm going to peel off

    your gold star and stick it on Bob . . .

    This, ladies and gents is what good critical review is all

    about. It's exceedingly east to get our tongues wrapped

    around our eyeteeth so we can't see what we're saying.

    Bob . . .

sportav8r(at)gmail.com
Guest

Posted: Mon Oct 30, 2006 10:26 am Post subject: "Electronics" is 100 years old this year

Okay, okay, I'll cede the point.  But conceptually, the grid is

controlling the current of electrons across the vacuum, and only

indirectly is it manipulating the voltage on the plate in the process.

 High enough grid signal voltage can actually make the electron

current reverse course and return to the cathode.  What does the plate

voltage do in that brief moment when the Edison effect cloud

collapses... I'm not sure.



Next, I suppose someone is going to say that we should model

transistors based on the voltages rather than the currents in the b-e

junction and the collector circuit.  I'll be really lost then.



Once in ages past, I learned some long-since forgotten lore about

vacuum tube transconductance, in units I think they called mhos, and

it was something like mu=I/E, which I'm sure must be where I got that

fuzzy notion that we were concerned with the effect of grid voltage on

plate current.  Well, I'm 50 now, and there's been alot of

(solid-state-derrived) RF radiated way too close to my head since

those days, so I guess I'm not a gold star-level ham anymore.  I will

take it in stride     Bending over...



-Bill B  /  rice box appliance operator, but I once fooled with

12AX7's, 6L6's etc.



Anymore I finds airplanes is easier to understand but less funs to mess up 



do not archive



On 10/30/06, Robert L. Nuckolls, III <nuckollsr(at)cox.net> wrote:

 	  Quote: 	
		   



 At 08:21 AM 10/27/2006 -0600, you wrote:



 >

 >

 >

 >

 > >

 > >     Bill, you get the gold star for the day in catching

 > >     the writer's error and bringing it to the attention

 > >     of interested individuals. Good catch!

 > >

 > >     Bob . . .

 > >

 > >

 >I think you guys are mixing up plate supply with plate voltage.  The

 >load resistor is between the supply and the plate.  When the current

 >increases, the voltage across the load resistor increases. Therefore

 >the plate voltage goes down.  There isn't anything wrong with the

 >original description.



     Good for you sir. Bill, bend over. I'm going to peel off

     your gold star and stick it on Bob . . .



     This, ladies and gents is what good critical review is all

     about. It's exceedingly east to get our tongues wrapped

     around our eyeteeth so we can't see what we're saying.



     Bob . . .

bob(at)bob-white.com
Guest

Posted: Mon Oct 30, 2006 5:52 pm Post subject: "Electronics" is 100 years old this year

On Mon, 30 Oct 2006 09:51:18 -0600

"Robert L. Nuckolls, III" <nuckollsr(at)cox.net> wrote:



 	  Quote: 	
		   

 

 At 08:21 AM 10/27/2006 -0600, you wrote:

 

 >

 >

 >

 >

 > >

 > >     Bill, you get the gold star for the day in catching

 > >     the writer's error and bringing it to the attention

 > >     of interested individuals. Good catch!

 > >

 > >     Bob . . .

 > >

 > >

 >I think you guys are mixing up plate supply with plate voltage.  The

 >load resistor is between the supply and the plate.  When the current

 >increases, the voltage across the load resistor increases. Therefore

 >the plate voltage goes down.  There isn't anything wrong with the

 >original description.

 

     Good for you sir. Bill, bend over. I'm going to peel off

     your gold star and stick it on Bob . . .

 

     This, ladies and gents is what good critical review is all

     about. It's exceedingly east to get our tongues wrapped

     around our eyeteeth so we can't see what we're saying.

 

     Bob . . .

 



 
	


Thanks Bob, but if I have to bend over I may not want that star. 



Bob W.



-- 

N93BD - Rotary Powered BD-4 - http://www.bob-white.com

First engine start 1/7/06 - Special Airworthiness Certificate 10/1/06

Cables for your rotary installation - http://www.roblinphoto.com/shop/

bob(at)bob-white.com
Guest

Posted: Mon Oct 30, 2006 5:52 pm Post subject: "Electronics" is 100 years old this year

Hi Bill,

Your thought process is exactly correct.  the transfer function is

voltage in current out.  If the grid is negative enough to cut off the

current flow, the plate voltage would equal the supply voltage.  You

would never have current flowing from the plate to the cathode.  And yes

the transfer function for a transistor is current in current out.  The

FET also has a voltage to current transfer function but in general the

shape of the function is closer to a pentode than a triode.  The trick

is to take whatever function you have and figure out how to build what

you need, which more often than not is a voltage in voltage out

amplifier.

I'm about 10 years older than you, and when I went thru tech school I

spent months learning about tubes, how they worked and how to design

with them. They were still in use when I entered the work force, but I

don't think I ever designed anything with them.  I remember building an

intercom when I was a teenager, but it hummed a lot because all my

filter capacitors came from old TV sets. 

Ah, yes!  The good old 6L6.  I think that was often used in the design

classes.

Bob W.

do not archive

On Mon, 30 Oct 2006 13:24:08 -0500

"Bill Boyd" <sportav8r(at)gmail.com> wrote:

 	  Quote: 	

 Okay, okay, I'll cede the point.  But conceptually, the grid is

 controlling the current of electrons across the vacuum, and only

 indirectly is it manipulating the voltage on the plate in the process.

  High enough grid signal voltage can actually make the electron

 current reverse course and return to the cathode.  What does the plate

 voltage do in that brief moment when the Edison effect cloud

 collapses... I'm not sure.

 Next, I suppose someone is going to say that we should model

 transistors based on the voltages rather than the currents in the b-e

 junction and the collector circuit.  I'll be really lost then.

 Once in ages past, I learned some long-since forgotten lore about

 vacuum tube transconductance, in units I think they called mhos, and

 it was something like mu=I/E, which I'm sure must be where I got that

 fuzzy notion that we were concerned with the effect of grid voltage on

 plate current.  Well, I'm 50 now, and there's been alot of

 (solid-state-derrived) RF radiated way too close to my head since

 those days, so I guess I'm not a gold star-level ham anymore.  I will

 take it in stride     Bending over...

 -Bill B  /  rice box appliance operator, but I once fooled with

 12AX7's, 6L6's etc.

 Anymore I finds airplanes is easier to understand but less funs to mess up 

 do not archive

 On 10/30/06, Robert L. Nuckolls, III <nuckollsr(at)cox.net> wrote:

 > 

 >

 > At 08:21 AM 10/27/2006 -0600, you wrote:

 >

 > >

 > >

 > >

 > >

 > > >

 > > >     Bill, you get the gold star for the day in catching

 > > >     the writer's error and bringing it to the attention

 > > >     of interested individuals. Good catch!

 > > >

 > > >     Bob . . .

 > > >

 > > >

 > >I think you guys are mixing up plate supply with plate voltage.  The

 > >load resistor is between the supply and the plate.  When the current

 > >increases, the voltage across the load resistor increases. Therefore

 > >the plate voltage goes down.  There isn't anything wrong with the

 > >original description.

 >

 >     Good for you sir. Bill, bend over. I'm going to peel off

 >     your gold star and stick it on Bob . . .

 >

 >     This, ladies and gents is what good critical review is all

 >     about. It's exceedingly east to get our tongues wrapped

 >     around our eyeteeth so we can't see what we're saying.

 >

 >     Bob . . .

 >

 >

 >

 >

 >

 >

-- 

N93BD - Rotary Powered BD-4 - http://www.bob-white.com

First engine start 1/7/06 - Special Airworthiness Certificate 10/1/06

Cables for your rotary installation - http://www.roblinphoto.com/shop/

nuckollsr(at)cox.net
Guest

Posted: Mon Oct 30, 2006 7:28 pm Post subject: "Electronics" is 100 years old this year

At 01:24 PM 10/30/2006 -0500, you wrote:



 	  Quote: 	
		  



Okay, okay, I'll cede the point.  But conceptually, the grid is

controlling the current of electrons across the vacuum, and only

indirectly is it manipulating the voltage on the plate in the process.


	


   Sure . . . and transistors do that too. The cause is a delta-I

   in a base or delta-E on a grid both of which effect a delta-I

   in the collector/plate. Whether or not there is a resulting

   delta-E in the output depends on source impedance of the supply

   such that if it's very low ohms, lots of current modulation can

   be go'n on with no discernable change in voltage.



 	  Quote: 	
		  High enough grid signal voltage can actually make the electron

current reverse course and return to the cathode.  What does the plate

voltage do in that brief moment when the Edison effect cloud

collapses... I'm not sure.


	


   Hmmm . . . don't recall taking it that far. I could go to

   the bench and try it. Yeah, I still have vacuum tubes laying

   around . . . and high voltage power supplies. I like to use

   vacuum tubes to teach elementary electronics. You can take them

   apart and TOUCH and SEE the things that make them work. Not

   so with the silicon.



 	  Quote: 	
		  Next, I suppose someone is going to say that we should model

transistors based on the voltages rather than the currents in the b-e

junction and the collector circuit.  I'll be really lost then.


	


   Doubt that. Whether you like with H-parameters, S-parameters,

   etc., the physics of the transistor doesn't change and external

   source impedances are readily accounted for in the performance

   predictions. Base delta-I still translates to collector delta-I.

 	  Quote: 	
		  Once in ages past, I learned some long-since forgotten lore about

vacuum tube transconductance, in units I think they called mhos, and

it was something like mu=I/E, which I'm sure must be where I got that

fuzzy notion that we were concerned with the effect of grid voltage on

plate current.  Well, I'm 50 now, and there's been alot of

(solid-state-derrived) RF radiated way too close to my head since

those days, so I guess I'm not a gold star-level ham anymore.  I will

take it in stride     Bending over...


	


   Awww shucks . . . you can keep the star. We're all friends here

   and I'm not sure Bob wants a 'used' one anyhow.

 	  Quote: 	
		  -Bill B  /  rice box appliance operator, but I once fooled with

12AX7's, 6L6's etc.


	


   The first RF I put on the air was from a 1-tube, 117L7 transmitter

   good for about 5w out. The receiver was a 6SN7 regen + one stage

   of audio. Used this combination for several months with reasonable

   success considering the equipment. Somebody gave me the functional guts

   of an SX25 sans case. Had to make dials but at least I had a REAL

   receiver. It was downhill from there! The next transmitter was

   a 6V6 driving an 807 . . . real flamethrower. That was the spring

   of '56. Been up to my eyeballs in electrons ever since.



   Bob . . .

sportav8r(at)gmail.com
Guest

Posted: Tue Oct 31, 2006 6:36 am Post subject: "Electronics" is 100 years old this year

 	  Quote: 	
		  

 >High enough grid signal voltage can actually make the electron

 >current reverse course and return to the cathode.  What does the plate

 >voltage do in that brief moment when the Edison effect cloud

 >collapses... I'm not sure.



    Hmmm . . . don't recall taking it that far. I could go to

    the bench and try it. Yeah, I still have vacuum tubes laying

    around . . . and high voltage power supplies. I like to use

    vacuum tubes to teach elementary electronics. You can take them

    apart and TOUCH and SEE the things that make them work. Not

    so with the silicon.



Isn't that what happens in a diode rectifier tube, and also a class-C
	


triode amplifier (and maybe for a brief % of the duty cycle in

everything from class AB on down), this biasing to cutoff?  That's

what I was referring to, but perhaps incorrectly.

 	  Quote: 	
		  

    The first RF I put on the air was from a 1-tube, 117L7 transmitter

    good for about 5w out. The receiver was a 6SN7 regen + one stage

    of audio. Used this combination for several months with reasonable

    success considering the equipment. Somebody gave me the functional guts

    of an SX25 sans case. Had to make dials but at least I had a REAL

    receiver. It was downhill from there! The next transmitter was

    a 6V6 driving an 807 . . . real flamethrower. That was the spring

    of '56. Been up to my eyeballs in electrons ever since.



    Bob . . .

You, sir, are _old_.  Spring of '56, playing with electrons, when I
	


was still in the womb...



It's been a fun thread.  BTW, the new Hyundai alternator isn't in yet;

it appears to be a "special order" item.  Perhaps it has a special

voodoo regulator inside   I'll check back with the mechanic today;

he promised me to save the core.



-Bill B

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