>Hello Rick:
>
>Richard escribió:
>>
>> > can anyone point me to a source of resistors other than mouser and
>> >digi-key???
>>
>> Dale makes high-ohm spiral-film resistors. I tested tw5 Dale, 55M-ohm.
>> 5Wers yesterday that performed well at 15kV (4W). The max V ability film
>> resistor I have been able to find at Digi-Key and Mouser is 2W, 1M -
>> which = 1414V.
>>
>> > I can't believe there aren't more resistors than what they
>> >list!!! I need some 750k -3w-either ww
>>
>> Wirewound resistors much over 100k-ohm tend to be semi-reliable.
>> High-value WW resistors usually carry a V-rating that limits power-rating
>> to less than the rated dissipation. For example, a 200k-ohm, 100W
>> resistor dissipates 100W @ 4472V, however, such a resistor typically
>> carries a max V rating of less than 4472V. In other words, the "100W"
>> rating is unsliced bologna at 200k-ohms. On the other hand, spiral-film
>> resistors seem to able to handle more V. I've used 400M-ohm, 5W
>> spiral-film resistors that could handle 40kV. To further complicate
>> matters, there are two V-ratings. One is end-to-end V-max and the other
>> is case-to-gnd V-max. In the example with the 400M unit, even though the
>> ene-to-end rating is 40kV, the case-to-gnd rating is probably <400V since
>> the spiral film is coated with a thin layer of paint so as not to
>> increase thermal resistivity between the cooling-air and the heat source
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