[Prev][Next][Index][Thread]

Re: Resistor-ERROR



> > > This is directed to John Freau, Is the resistor on the schematics a 12k
>>> 100w
 >> >meaning a 12,000 ohm- 100 watt resistor? Im having trouble finding this
> >> value
>> > and wondered if I was reading it correctly.  Stephen S
 >>  >     SSNSanders-at-aol-dot-com
 >  
 >   >>
 >> Yes, you're reading it correctly.  Anything from 10 k to 15 k should be
> > acceptable.  also you can put two 25k resistors in parallel, or two 6k
>> resistors in series, etc. as long as the result is approx what you want. 
>> A
> > lot of this stuff is  approx.  use what works best.  You also may be able
>>to
 >> find an adjustable resistor that has a sliding tap so you can set the
>> resistance at any value within the range.
 > 
 >> John Freau
 
> John,
>I think the emphasis of the question was not so much on the 12K ohm aspect,
> but the
> 100 Watt aspect. That is a HUGE resistor wattage, not something you can
>pick up at Radio Shack, that's for sure. 
 
>According to my calculations a 12K 100W resistor will dissipate 100W when
> rhe current through it is 91 ma and the voltage across it is 1095 Volts.
> Ummmm, that seems a bit high to me. What is the calculated or measured grid
> voltage? Use that to caluculate the power rating, and then multiply by two
> as a safety factor.
 
> I have a 12K 100 watt resistor here in front of me, and it measures 1 inch
>in diameter and is six inches long. Are you sure you need One Hundred Watts
> for the grid resistor?
 
 >Fr. Tom McGahee
  >

Tom, Tube Coilers,

You're absolutely correct, the resistor needs to be only about 20 watts.  The
100 watt value was a carry-over value from some of my larger tube coils.
 Sorry for any confusion or inconvenience.

Happy low-wattage coiling,

John Freau