robert bristow-johnson wrote:> On Aug 27, 5:58 pm, Jerry Avins <j...@ieee.org> wrote: >> Tauno Voipio wrote: >>> robert bristow-johnson wrote: >>>> i remember Eimac back when i was a ham radio operator in the 60s and >>>> early 70s. i was WN0CCA and WB0CCA. > ... >>>> hey Tauno, thanks for stimulating some 40 year old synapses that i >>>> didn't realize i still had. >>>> geez, i'm getting old. >>> In the sixties, I dreamed of big Eimac tubes. I still >>> have a linear with a pair of Eimac 3-500Z's. >> Speaking of forced air and special sockets, I still have a 4X150A in the >> attic. > > dunno what the 4X150A is but i remember the 3-500Z. it was the > classic old glass envelope 500 W triode (usually in grounded grid, it > seemed very weird to me that the driver was connected to the cathode > filaments, there was no separate heater and cathode, still seems > weird). Heathkit had a linear amp with a pair of them (don't remember > the model number, but it matched their SB-102 SSB transceiver, it was > green). these were really common in ham linear amps.This starts to be OT, but ... Let's decode the Eimac codes: 4X150A 4 = tetrode X = external anode 150 = max anode dissipation, watts A = version 3-500Z 3 = triode 500 = max anode dissipation, watts Z = zero-bias Class B tube The 4x150A is a glass-bubble type of external-anode tube, one of the very first. The later external-anode tubes are of the CX series, where the glass bubble is replace with ceramic rings. Some types are 4CX250B and 4CX1000A. ---- The Heathkit linear with the 3-500Z's is SB-220 (which mine also is). -- Tauno Voipio
Complex versus real numbers
Started by ●August 25, 2009
Reply by ●August 28, 20092009-08-28
Reply by ●August 28, 20092009-08-28
On Thu, 27 Aug 2009 10:30:42 -0400, Jerry Avins <jya@ieee.org> wrote:> invalid wrote:> What do you say to those who claim that exp(ix) is a fundamental > abstraction, and that sin(x) and cos(x) are derived abstractions?I think I'd ask to see their deriver's license and registration. Frank McKenney -- The vice of the modern notion of mental progress is that it is always concerned with the breaking of bonds, the effacing of boundaries, the casting away of dogmas. But if there is such a thing as mental growth, it must mean the growth into more and more definite dogmas. The human brain is a machine for coming to conclusions; if it cannot come to conclusions it is rusty. -- G.K. Chesterton: Concluding Remarks on the Importance of Orthodoxy (1905) -- Frank McKenney, McKenney Associates Richmond, Virginia / (804) 320-4887 Munged E-mail: frank uscore mckenney ayut mined spring dawt cahm (y'all)
Reply by ●August 29, 20092009-08-29
"Les Cargill" <lcargill@cfl.rr.com> wrote in message news:4a96a15b$0$19122$9a6e19ea@unlimited.newshosting.com...> Randy Yates wrote: >> Jerry Avins <jya@ieee.org> writes: >>> [...] >>> Some people seem to believe that mathematics is reality and the things >>> we touch are only Plato's shadows on the cave wall. >> >> Define "reality"... >> >> No, really - try it. I have and never reached a final verdict. > > Reality is that which does not change when you ignore it. > > -- > Les CargillComplexity does not go away when you ignore it... At least not if it's real complexity...
Reply by ●August 29, 20092009-08-29
On Aug 27, 9:18�am, Jerry Avins <j...@ieee.org> wrote:> > Some people seem to believe that mathematics is reality and the things > we touch are only Plato's shadows on the cave wall.i wonder how apt this Plato's cave allegory is in light of the recent emergence after 18 years of kidnap victim Jaycee Dugard. not exactly Plato's cave. r b-j
Reply by ●August 30, 20092009-08-30
In article <f8abf650-5d35-401f-8f88-09514f45cd8c@z28g2000vbl.googlegroups.com>, brent <bulegoge@columbus.rr.com> wrote:>On Aug 27, 4:39=A0am, "Gary" <inva...@invalid.invalid> wrote: >> "brent" <buleg...@columbus.rr.com> wrote in message >> > >> >> "Two little atoms, >> Walking home from school, >> Bumped into each other, >> And made a molecule" > >I like your thinking. If we can somehow get some kind of pornographic >theme going with complex numbers mating together or something, maybe >we can get more people to understand them. > >Well, come to think of it, we do use the word "conjugating" when >dealing with complex numbers, maybe we should change that to something >else. > >Lets see: two complex numbers conjugate to form a real number. > >How about: Two complex numbers __ck around to form a real number?You mean "copulate". That is a nice, decent Latin word to use, and not overloaded much in mathematics.> >That should get Chris Bore's clients attention. > >Groetjes Albert -- -- Albert van der Horst, UTRECHT,THE NETHERLANDS Economic growth -- being exponential -- ultimately falters. albert@spe&ar&c.xs4all.nl &=n http://home.hccnet.nl/a.w.m.van.der.horst
