Tubes Asylum Questions about tubes and gear that glows. FAQ |
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In Reply to: Oops! Too right... I shouldn't have popped in mid stream :) posted by David S. on August 13, 2002 at 17:18:47:
when the tube is operating, most of the heat transfer is through radiation, goes as fourth power of absolute temp, delta T is about 180-200 K between operation temp of plate and surroundings. This is why a smaller EL34 plate is good for 25 W and the bigger KT88 is rated at 42 Watts. Sinking the thing in liquid N2 gives the same delta T between surroundings( the coooold liquid N2, and the tube's innards 270 K. of course some will be transfered through the pin connections, but look at how thick the connections are ( effective resistance ) and the mass of material bahind it ( model as capacitance ). anyway, just had to put in two Cents...
regards,
Douglas
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Follow Ups
- I think it's radiation, here's why... - Sector-7G 17:51:36 08/13/02 (0)