Re: reason for rf chokes?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "rheidlebaugh by way of Terry Fritz <twftesla-at-qwest-dot-net>" <rheidlebaugh-at-zialink-dot-com>

Laurence: Ohms law is E=IR  If a resistor is 1000 ohms and drops 10v the
current throuhg the resistor is 10 ma and disipates 0.1 watt . If you use a
1000 ohm 100 watt wire wound resistor as a choke with 275uh of inductance
you dont disipate 1.4Kw with the resistor/choke in series with the voltage
supply. If you short the supply and put all power to the resistor you will
burn out your resistor and power supply.
      One RF ground is sufficent unless you  are trying to set up a zero
noise laboratory vault in an old mine shaft below the water table with a
copper fariday cage in a nichel room. The secondary is low current of a few
milli amps and is connected to earth/RF ground to keep the potential low in
refrance to ground where you are standing. The top of the secondary is
connected to your toroid or air terminal and is a high potential in refrance
to ground. Your PRIMARY is high current with pulse currents well over 400
amps. That is why copper tubing  or straps are often used as wire.
      Robert  H 

> From: "Tesla list" <tesla-at-pupman-dot-com>
> Date: Sun, 11 Aug 2002 10:32:31 -0600
> To: tesla-at-pupman-dot-com
> Subject: Re: reason for rf chokes?
> Resent-From: tesla-at-pupman-dot-com
> Resent-Date: Sun, 11 Aug 2002 10:41:59 -0600
> 
> Original poster: "Laurence Davis by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <meknar-at-hotmail-dot-com>
> 
> two more basic nst filter questions.
> 
> using the rc filter design, the pair of caps are tied to rf ground.
> as well as the safety gaps to rf ground.  does that mean i need another
> ground rod or can i use the same one im using for my secondary?  i'm asking
> because in my mind that doesn't sound safe.  As in it would cause excess
> signal noise... (perhaps i'm wrong, since the bottom of the secondary caries
> low voltage high current.)  and if I have poor grounding (i have two four
> foot zinc coated threaded stock 5/8 dia for ground rods,) then the rc filter
> wouldn't work as well compared to a better rf ground.  or am i just
> splitting hairs?
> 
> I had previously looked at a rc filter design, but ruled it out.  why?
> because the two caps tied to the high voltage side, to me, looked like a
> short.  i figured the caps would just go up in smoke and the hv caps would
> be junk.
> 
> in sizing the resistors, (just wanted to make sure i get this right)
> 12kv/120ma = 1440watts. there for each resistor would need to be a minimum
> of 720 watts? or would i multiply 12kv x sqrt(2) for true voltage?
> thus...2036 watts, 1016watts min.
> 
> and here i beat the dead horse.
> a choke can be a filter. a cap can be a filter. a resistor cannot filter by
> itself. an rc filter: the cap has a charge time, the resistor increases the
> charge time. an lc filter: the cap has charge time, the inductor acts like a
> frequency relative resistor which affects charge time with regard to
> frequency. i understand some of the basics, but the portion of the
> resistance doesn't ring right with me. (bad pun, sorry :)
> 
> larry.
> 
> 
>