From: gherold@teachspin.com   
      
   On Monday, April 2, 2018 at 12:10:15 PM UTC-4, Jim Thompson wrote:   
   > On Mon, 2 Apr 2018 07:33:35 -0700 (PDT), George Herold   
   >  wrote:   
   >   
   > >On Saturday, March 31, 2018 at 10:58:02 AM UTC-4, Jim Thompson wrote:   
   > >> On Fri, 30 Mar 2018 18:09:01 +0100, Peter Percival   
   > >>  wrote:   
   > >>   
   > >> >I wish to experiment with valves (or tubes, if you prefer) and I shall   
   > >> >begin by building a power supply.  What voltages (at what currents)   
   > >> >should it supply?  Where may I find circuits?  Naturally, the devices   
   > >> >used should be easily obtainable.   
   > >>   
   > >> Typically?  Probably around 350VDC for the plate supply, 6.3VC and/or   
   > >> 12.6VAC for filaments.   
   > >>   
   > >> As for the naysayers... there are still lots of things better done   
   > >> with toobz than semiconductors.   
   > >>   
   > >> It's always puzzled me that someone hasn't created a bipolar/tube   
   > >> combo part that has the best of both worlds ;-)   
   > >   
   > >Tubes are expensive. (and fragile)   
   > >How many $0.05 transistors does it take to replace a $50 tube?   
   > >   
   > >Beside PMT's are there any tubes being made these days?   
   > >(They even stopped making those two terminal light emitting tubes,   
   > >incandescent bulbs :^)   
   > >   
   > >George H.   
   > >> 		   
   > [snip SIG left by crap newsreader software]   
   >   
   > How many hoops do you have to jump thru to make an amplifier that   
   > outputs 1000V P-P?   
   Sure some niche applications.  How many 1kV amps have you made in your life?   
   (I've done zero.  I guess I'd start with a 100V opamp and a 1:10   
   transformer, but then 'an opamp' is the hammer I hit all nails with. :^)   
      
   Hey I do have a ~200 Vp-p oscillator that runs a Rubidium lamp.   
   (It's probably less that 200V once the lamp warms up and the coil   
   get loaded down by the Rb vapor.)   
      
   There was a monstrous (~6 foot) klystron that pulsed the linear   
   accelerator at the Vanderbilt FEL.  High power/ voltage stuff is   
   cool and scary.   
      
   George H.   
   > 		   
   >                                         ...Jim Thompson   
   > --   
   > | James E.Thompson                                 |    mens     |   
   > | Analog Innovations                               |     et      |   
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   >       Understanding is a fountain of life to one who has it,   
   >       But the instruction of fools is folly.  Proverbs 16:22   
      
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