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Re: Tube watts & volts

sorry, listees. We were holding out on a little off-list correspondance,
while threads spawned of similar stuff were running. 

Grayson

On Sat, 3 Jul 1999 23:16:19 EDT Parpp807-at-aol-dot-com writes:
>In a message dated 7/3/99 10:10:39 PM Central Daylight Time, Par pp 
>807 
>writes:
>
><< Subj:	Re: Tube watts & volts
> Date:	7/3/99 10:10:39 PM Central Daylight Time
> From:	Par pp 807
> To:	electrofire-at-juno-dot-com
> 
> In a message dated 7/2/99 11:38:15 PM Central Daylight Time, 
>electrofire-at-juno-dot-com writes:
> 
> << Thanks, I think I understand what you're trying to explain, up to 
>the
> >> point of delta. (snip)
> >> I know it is dealt with in power systems, (big snip)
> 
<snip>

> Some of the other postings were helpful. A few, I thought, 
>misunderstood 
>your question but perhaps I am misunderstanding. Several answers 
>explained 
>about the DC and static ratings. About the only other way to put it is 
>that 
>plate dissipation is
> the difference (P out - P in) where P in is the plate dissipation and 
>P out 
>is the power
> delivered the load like I 'splained last time.

Okay, so plate dissipation is a loss of power in heat form?

> 
> Sorry about the delta.  A delta sign means small change so that delta 
>Ip=Ip2 
>- Ip1.

Oh, yeah! NOW I remember, sort of looks like a triangle, used a lot in
chemical equations. Means, "change in", and is paired with a variable.

> See how ascii is impossible for teaching purposes. I need a 
>blackboard! The 
>FAX
> is far superior to this. Does that help? 

'fraid not. Unless a certain friend nearby...  ..let me get back to you
on that. 

>How old are you? 

17. Seven months down and counting...
>  
<snip>
> There is no zero = zero. The zero is an arbitary reference point 
>called the 
>bias point
> or bias voltage. Think of the grid voltage as a fulcrum point. If the 
>
>fulcrum (bias voltage) is set at a minus 10 V, A sinusoidal signal may 
>swing 
>above and below the 
> bias voltage to -5 V to -15 V. But that's a +5 to -5 or a 10 V change 
>in Eg 
>which
> produces a change in Ip. That's the delta Ip and it is what produces 
>the Eg 
>Ip curves
> for the particular tube. That small change in the grid voltage causes 
>a 
>similar change in the plate current. See previous mailing.  
>
So, delta Ip is proportional to delta Eg?

The Ip is formed into a sine wave, but usually never reaches cutoff,
unless the Eg becomes negative enough.../(bias being set to so so?)
  
>  >>Oops, just re-read your message. The tube controls current, not 
>voltage.
>  >>An increasingly negative grid decreases current till it reaches 
>the point
>  >>of cutoff, where the tube doen't conduct.<<
> 
> Yes, that is correct! A+!. I'll never forget how thrilled I was when 
>I first 
>saw the
> plate-current (Ip) meter swing back and forth as I talked into the 
>microphone. Then,
> see it on an oscilloscope and the mystery is solved, because the name 
>of the 
>game
> is voltage regulation and the need to keep the voltage constant under 
>
>varying load.
> That's why we built expensive power supplies.

I think we're edging towards an area not entirely concrete with me. The
input voltage would drop because--? drawing too much current?

 So if the voltage 
>remains 
>constant
> while Ip follows the swings of Eg, you have controlled the high input 
>power 
>of Ep x Ip to transfer an even larger output power to the load because 
>the 
>delta Ip increases
> the power. Doesn't it?

Just to be sure, are you saying that along with the power of Ep x Ip, the
rise in Ip increases the output power additionally?

> 
I know some of my questions are naive, but I'm just asking to be sure,
since I know little, and am trying to grasp what you are saying. I'd hate
to need extra explanations of old concepts along the line when I suddenly
realize that I'm lost.

> >> ? If I try to see this(tube
> >> output) as a sine wave, it would be composed of entirely postive 
>values,
> >> except for the cutoff, which would touch the x-axis. right?
> 
> Maybe you wanna think about what you are saying here. We need 
>diagrams.
> ascii sucks!!!

I was trying to visualize the sinusoidal nature of Ip. I see now that the
troughs don't neccesarily have to reach "zero", and the amplitude is
equal to max Ip - min Ip. ??
> 

The tube is driving an oscillator... if it controls only the current, and
doesn't ever conduct in the opposite polarity, what functions to change
the polarity of the voltage all those cycles?


> >> The 811-A will give off 65 watts of heat, unchanging, when the 
>plate is
> >> continuously as positive as it would dare be made? The value of 65 
>will
> >> become negative?<<  No, no. The heat radiated must increase with
> increased power. 

sorry-- that's what i get for late-night reading and responding. I know
watts can't be negative... 

> 
> Power (watts) has no polarity. It is not a vector. Do you know about 
>vectors?
 
I probably know about them, just not by name. 

> >>Is this the tube conducting in the opposite direction?<<
> 
> Never happens. Conduction is from the negative cathode to the 
>positive anode.
>  
<snip>

<snip>

  
>  <snip>
>  >
>  >Who is Brent Turner? Book title?
>  
>  Tesla Coiler, author of, I believe, "The Tesla Coil Book, What They 
>Are
>  and How They Are Built"
>  ex-listee, mentored by Bill Wysock, participated in 1992 Tesla 
>Symposium
>  in Colorado Springs in helping Bill demonstrate his twin system. His 
>book
>  is available via him, with an add in his website.<<<<<<<<<<<<
> 
> I would like to check that out. URL, please.  

http://www.apc-dot-net/bturner/t-page_2.htm

that might not be right, since It's old, and not checked, but it probably
will take you to somewhere in his site.

>  >
>  >Grayson,
>  >The plate voltage and current are the static no-signal values.
>  
>  So, 1500Vpeak, to be safe. ?
>  
>  Back in 
>  >the 
>  >days when the FCC kept its paws off of my phone bill, Ep x Ip was 
>  >known as 
>  >the input power. The plate
>  >dissipation in watts is the heat produced by the plate as it 
>catches 
>  >all the 
>  >electrons
>  >flowing from the filament. It is a static value. These values swing 
>
>  >plus and 
>  >minus when a
>  >signal is applied to the grid. A negative grid decreases Ip, a + 
>grid 
>  >increases Ip. This plate
>  >current flows thru the primary of a transformer-iron core for audio 
>
>  >and air 
>  >for RF. As the signal changes, (usually a sine wave) the plate 
>current 
>  >can 
>  >increase so that the delta Ip
>  >has instantaneous values reaching 200% of the static, no-signal 
>value. 
>  >The 
>  >output power
>  >and the efficiency increase as the Eg drives positive and the plate 
>
>  >current 
>  >(Ip) increases.
>  >This explanation sucks badly because of the lack of diagrams. Also, 
>I 
>  >don't 
>  >know where you are at on the math thing.  I never learned ASCII 
>math. 
>  >It 
>  >sucks. 
>  
>  Yeah, I've tried writing a few formulas with ASCII, for list 
>newbies, and
>  the insane amount of ([{}]) needed makes it nearly impossible to
>  decipher. Along with the absence of mathematical symbols and
>  notations..., and subscripts or superscripts...
>  
>  >
>  >This stuff is impossible to explain under the constraints of ASCII. 
>I 
>  >suggest 
>  >you get hold of a copy of the RCA Tube Manual, Terman's, Henny  
>and/or 
>  >the 
>  >ARRL Handbook, all from
>  >around 1950-1960. Try the ham fleamarkets and eBay. You have to 
>study 
>  >about 
>  >tube bias.
>  
>  I've been thinkingf about the possibilty of finding an old copy of 
>the
>  ARRL handbook for a while now. Several other people have suggested I 
>do
>  so. >>>>>>>>>>>>>>
> 
> Lots of goodies at the Dayton Hamfest next spring.
> Also check Antique Electronics in Tempe, Ariz.
> I am beginning to pickup vibes that you are interested in VTTC's. Is 
>that 
>why you keep asking about operation at or near cutoff? One of my many 
>projects now is
> more work on a VTTC. I built one with a schematic from a 1942 issue 
>of 
>Popular
> Science. More if you are interested. John Freau is the expert on tube 
>coils.
> 
> Please be very careful with that 500 mA transformer. Plate 
>transformers are
> totally unforgiving.

Which transformer? I'm unaware of the current capabilities of the MOT's I
was thinking of using. BUt I suppose that 500 ma is as good an estimate
as any. Could use the core size, the chart in the back of the 1992 ARRL
handbook, and Vout to find this a little more accurately.

BTW, one of the MOT's has been used to charge two 2kv 500uF (but it says
mF, ~!!!-at-#$%#) which are used to explode wires. Can crusher in the
future... 

> 
> Good Sam Adams to ya,
> Ralph Zekelman
> Bloomington, Indiana 
>  
>  >I thought it best to send you this off-list because the topic is 
>off 
>  >the TC 
>  >subject. 
>  
>  I dunno... I'm asking since I want to build a tube-driven TC ;-)
>  
>  Maybe someone else will give you a better explanation. Feel 
>  >free to 
>  >ask any questions.
>  
>  well, you offerred!
>  
>  >It's pool time :-))
>  >Cheers,
>  >
>  >Ralph Zekelman >>
>  >>

'tanks again, Ralph. 


-The Electrophile-
Grayson Dietrich,  Medina, OH
See my HV Haven (it does NOT do jusctice!)
www.geocities-dot-com/WestHollywood/Stonewall/2509/index.html

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