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

Measuring C, HV Resistors, etc.




----------
From:  Steve Young [SMTP:youngs-at-konnections-dot-com]
Sent:  Monday, June 08, 1998 11:55 PM
To:  Tesla List
Subject:  Re: Measuring C, HV Resistors, etc.


> From:  D.C. Cox [SMTP:DR.RESONANCE-at-next-wave-dot-net]
> Sent:  Monday, June 08, 1998 11:30 AM
> To:  Tesla List
> Subject:  Re: Measuring C, HV Resistors, etc.
> 
> to: Steve
> 
> Happen to have a tel number and address for Tech America??
>
Yup:  Catalog order is 1-800-303-4450 ext 2105.
      Parts order is 1-800-877-0072.
      Fax parts order is 1-800-813-0087.

They are a mail order outfit, with address of P. O. Box 1981
                                              Fort Worth, TX 76101-1981

But they have walk-in stores in Denver and Atlanta.

Hams might know the VP of the company - Bob Miller, K2RM.  

--Steve

 
> DR.RESONANCE-at-next-wave-dot-net
> 
> 
> ----------
> > From: Tesla List <tesla-at-pupman-dot-com>
> > To: 'Tesla List' <tesla-at-pupman-dot-com>
> > Subject: Measuring C, HV Resistors, etc.
> > Date: Sunday, June 07, 1998 10:21 PM
> > 
> > 
> > ----------
> > From:  Steve Young [SMTP:youngs-at-konnections-dot-com]
> > Sent:  Saturday, June 06, 1998 11:42 PM
> > To:  Tesla List
> > Subject:  Measuring C, HV Resistors, etc.
> > 
> > To all,
> > 
> > 1) Every now and then, someone posts their need for inexpensive way to
> > measure C.  A great source for all sorts of parts is Tech America. 
Their
> > catalog is available at Radio Shack, or you can get one via their
website
> > at www.techam-dot-com.  They sell a kit (part number 990-0043) for $13
which
> > lets one use a DVM to measure 2pf to 2 mf.
> > 
> > 2) Occasionally, coilers indicate a need for HV resistors.  If you
don't
> > mind a lot of soldering, you can make your own very cheaply.  Tech
> America
> > sells resistors for 100 for a dollar.  Use 1/2 watt resistors which
have
> a
> > rating of 350 volts.  For example, suppose you have a 20,000 ohms per
> volt
> > meter which can measure 5 KV, but you want to measure up to 15 KV. 
Just
> > add 67 3 meg 1/2 watt resistors (200 meg) in series with the test lead
> and
> > presto, you have a 15 KV meter.  Cost is 67 cents.  The resistor string
> > will be good for at least 23 KV and can dissapate 20+ watts.  Be sure
to
> > arrange the ends of the resistor string so the HV doesn't flash over
> > possibly resulting in a fried meter.  It would help to put the string
in
> > oil to reduce corona and improve heat dissapation.    
> > 
> > If you don't care about the exact value of the HV resistor, then
another
> > easy solution is to use plastic tubing filled with tap water.  Push
wires
> > through plugs in the ends of the tube.  Such resistors work great in a
> Marx
> > generator, for example.  Just be sure the wires in the tube are at
least
> a
> > few inches apart so they don't arc over and explode!  Even though the
> > resistance is not very predictable, you can still make an accurate
> voltage
> > divider.  For example, a hundred foot hose with a electrode pushed
> through
> > at the 1 foot spot would make a 100:1 voltage divider which could
handle
> > many KV.  
> > 
> > 3) Tech America has just started carrying a line of Amidon toroidal
> cores. 
> > Biggest ones are 2 inches O. D.  
> > 
> > --Steve
> > 
> 
>