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| Cf = 700 pF @ 6 kV (cap filter) = three polipropilene caps 2.2 nF @ 2000 volts each, connected in serie). D = string of 15 diodes 1N4007 (1000V@1A) The cooler (from a microwave oven) is mounted under the tube to lower the temperature of the ceramic socket and the connections. Ls: R = 0.98", H = 18.11", N=2500 turns, Lsec=31605.413 microH, Cself= 6.0959 pF, Fres = 362.7 kHz bottom primary: R=2.75", H=3.54", N=24 turns, L= 72.4189 microH, Cself = 6.8562 pF upper primary: R=2.16", H=3.14", N= 10 turns, L=9.1770 microH, Cself= 5.2717 pF Cp = 763.8 pF @ 12 kV Cg1 = 733 pF @ 6000V Rg1 = 100 kohms@ 40 watts Rg2 = 20-40 kohms@400 watts I calculated that for 4200 VDC on plate and a maximum current (200mA) through grid 2, I would need a 21 Kohms high wattage resistor for Rg2. I had not the possibility of aquisition of such a beauty so I tryed a trick. A little light bulb 220vac@25watts has an ohmic resistence = 1936 ohms. So, I connected 20 light bulbs of this kind in serie for a 38.72 kohms@400 watts resistor. Using the connections between the light bulbs I can vary Rg2 between minimal 21 kohms (10 bulbs in serie) and the maximal point (38.72 kohms). For this value the top discharge is longer. For Rg2 values near 21 koms the current of the discharge increase and the flame become more bushy (shorter though). Here is a picture of my high wattage resistor: |
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| For now I am using 12 bulbs in serie for a value of 23.23 kohms@300 watts |