RE: ...sounds totally newbie, but...

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

Original poster: "Jim Lux by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

But, from a load standpoint, the C isn't in the picture... ideal/lossless/etc..

the 220K is the entire loss mechanism..

And, of course, the original request was for something that could be used 
as a dummy load in place of the secondary, so you need to reflect the 
"spark load" back to the primary, hence the 100 or so ohms

At 05:04 PM 1/31/2003 -0700, you wrote:
>Original poster: "Terry Fritz" <teslalist-at-qwest-dot-net>
>
>Hi,
>
>I have some foot long 200K power resistors.  But I think you also need a 
>say 5pF cap in series too that needs to take like 250kV!!  If anyone wants 
>to experiment, I would be happy to donate the resistor part.
>
>Cheers,
>
>         Terry
>
>
>At 03:53 PM 1/31/2003 -0800, you wrote:
>>If you're just trying to tune the primary, etc... and want to dump the 
>>energy, why not a resistor in the circuit that provides a load comparable 
>>to that of the secondary.   I believe that Terry modeled the secondary 
>>load as a 220K resistor with reasonable success (comparing waveforms 
>>against spice).. So.. if you could transform that 220K at the secondary 
>>to something equivalent in the primary.
>>
>>Another way to choose the resistor would be to calculate the approximate 
>>reactance of the primary at your approximate resonant frequency and then 
>>use a resistor that is 10-15 times that (i.e. a loaded Q of 
>>10-15).  Sample calculation: 0.08 uF primary capacitor, 200 kHz...  about 
>>10 ohms reactance.. so a 100-150 ohm resistor  might work..
>>
>>ystems.tk
>>>
>>> > -----Original Message-----
>>> > From: Tesla list [mailto:tesla-at-pupman-dot-com]
>>> > Sent: Friday, January 31, 2003 4:41 PM
>>> > To: tesla-at-pupman-dot-com
>>> > Subject: Re: ...sounds totally newbie, but...
>>> >
>>> > Without the secondary in place, the gap dissipates almost all the
>>> > power as
>>> > heat.  The primary current is also maybe 2X higher.  That is
>>> > "maybe" ok,
>>> > but just be aware of it.
>>> >
>>> > Operating without the spark gap with resonant sized caps is a sure killer
>>> > of NST or caps.  But having the spark gap in circuit should
>>> > protect in that
>>> > case since the gap will keep the voltage from going too high.