On Jun 3, 8:14*pm, Richard Clark wrote:
On Thu, 3 Jun 2010 12:08:42 -0700 (PDT), walt wrote:
Data from Terman’s example on Page 449 of Radio Engineers Handbook:

(1) Eb = DC Source Voltage = 1000 v.

From your own data
Eb = DC Source Voltage = 800 v.(2) Emin = Eb - EL = 1000 - 850 = 150 v. [See Terman, Figs 76(a) &
76(b)]

You do not supply context for me to apply to your data.(3) Idc = DC Plate Current = 75.l ma. 0.0751a.
Idc = 260mA
(4) EL = Eb - Emin = 1000 -150 = 850 v. = Peak Fundamental AC Plate
Voltage

You do not supply your minimum nor maximum plate voltage swing.(5) I1 = Peak Fundamental AC Plate Current = 132.7 ma. 0.1327 a.

You do not supply your peak AC Plate current.(6) Pin = Eb x Idc = DC lnput Power = l000 x O.0751 = 75.l w.
Pin = 208W
(7) Pout (Eb - Emin)/2 = ELI1/2 = Output Power Delivered to RL =
[(1000 -150) x 0.1327]/2 = 56.4 w.

You report Pout, but we cannot use this formula for lack of data.
Pout = 100W(8) Pd = Pin - Pout = Power Dissipated in Dissipative Plate Resistance
Rpd = 18.7 w,

From your report of Pin and Pout:
Pd = 108W(9) Rpd = 18.7W/0.0751^2 = Dissipative Plate Resistance Rpd = 3315.6
ohms

From what is reported by you:
Rpd = 108W/(.260mA)²
Rpd = 1597 Ohms(10) RL = (Eb - Emin)/I1 = EL/I1 = Load Resistance = 850/0.137 = 6405
Ohms (6400 in Terman)

You do not report Emin but you report Load Resistance
RL = 50 Ohms(11) Plate Efficiency = Pout x 100/Pin = 56.4 x 100/75..1 =
75.1%

Plate Efficiency = 48%

By all reckoning according to your reference from Terman, using what
you report, it appears that you have exhibited a Conjugate basis Z
match as you claim, and that the plate Rpd by the same reckoning is
the same as we formerly arrived at Rp. *It would appear that over the
course of some dozen years between publications that Terman simplified
the term Rpd to Rp which, according to you, is not found in your
volume, and as such this migration of terms seems logical by the
numbers agreeing in both volumes for different labels. *Inasmuch as
Rpd does not appear in Terman's later work, nor in any of the Tube
specifications since that era, Rpd appears to be an orphan.

You report your own Rp (now Rpd) or its equivalent by resistor
substitution (a valid determination) to be on order of 1400 Ohms. This
conforms closely to the value found above, and the data reported by
RCA for Rp in a design of similar characteristics. *The range of
possible values taken from RCA: 900 Ohms to 1500 Ohms.

Taking your low, the high from my range, and the higher computed
through your supplied data using Terman's formula, the average is 1500
Ohms with a variation of roughly 6% which is about the limits of
superlative accuracy for conventional bench equipment. *What this
means is that all three values are identical on the basis of
accumulation of error.

Having said that, this is not the end of analysis. *However, at the
first pass your data has demonstrated that the Plate serves as a real
resistor dissipating half of the available power being supplied to a
load that is conjugately matched. *

The only difference is that you state as much, but dismiss the plate
dissipation as being a real resistor. *Perhaps I mis-state you. *If
not, I take issue with that and ask once again, as this perception is
unique to your hypothesis, do you have data that differentiates the
resistance of steel absorbing and dissipating the impact of the
electron stream as being different from carbon absorbing and
dissipating the impact of the electron stream?

Would it serve to replace the steel plate with a graphite one like the
845 (similar to the GM-70)? *When I review the spec sheets for this
tube, it reports an Rp of 1700 Ohms - hardly remarkable at 100 more
Ohms than the computation above. *Of course, there are compounding
application differences, but still, graphite plates or steel don't
seem to force a new conclusion. *Materials don't seem to be an issue.

Certainly the mechanisms of resistance differ in the kinetics of
speed, but not in the product of heat. *To my knowledge, no authority
bases the concept of resistance upon the speed of the electron, but
rather in the kinetics of its collision.

73's
Richard Clark, KB7QHC

Richard, I'm totally shocked by what I've read above. I can't believe
it! I can't believe you've distorted what I've written in my last post
above to the extent that I can't possibly clarify or correct it--it's
more than just misunderstanding. In addition, it's totally misleading
to other readers of this thread, and makes me appear as a moron and an
idiot.

Sorry, Richard, I'm through with this thread. There's nothing I can do
now to fix the situation.

Walt, W2DU