Re: Transformer CGI program

To: neon-l@netcom.com
Subject: Re: Transformer CGI program
From: kenny@neonshop.com (Kenny Greenberg)
Date: Sat, 14 Oct 1995 08:08:26 -0400 (EDT)
Reply-To: neon-l@netcom.com
Sender: owner-neon-l@netcom.com


>I compared the numbers against the chart in the Neon bible, and these
>figures seem overall higher than the chart.  However, I trust the
>numbers above more than an 70 year book, especially since these numbers
>have worked for Kenny in the past.

The chart in the older Miller book does indeed have lower values than the
modern charts.  

>The chart indicates a curve which has an 1/r shape (makes sense from
>electromagnetc theory proof using Greens functions), so I fit the 3 data points
>to the form: Volts/foot = A + B/(tube diameter), and got (for A and B)
>   neon:       -60 for A and 4200 for B 
>   argon+merc: -20 for A and 2850 for B
>I have attached a uudecoded graph (postscript) of the neon curve from
>8 to 20 mm tubing diameter.

The neon tubes characteristic @60hz most closely follows that of a diac. Or
I should say it's the other way around to be chronologically correct.  In
most high frequency applications, it acts more like a capacitor.

Neon has a much higher breakover voltage than argon-mercury making it's
curve relatively spiked and then square while argon-merc though similar is
smoother.  Neon is noisier than argon-merc.  

>
>The chart in the book appears to have higher terms (C/(diam)^2 + ...),
>but could only fit to 2 variables with 3 data points.

Another factor is the greater heat generated by smaller tubes.

Probably, a good way to do the program is to use the volts per foot but also
do a lookup on the table.  The main problem with the table is when you go
from one diam to another and one gas to another etc - though it's certainly
possible, you have to do some guessing and I find that under these
circumstances the chart is almost always low.

Now krypton, that's a gas of a different color (and electric
characteristic)..   

Kenny

Kenny Greenberg   Neon Artist, Scenic Specialist, Columnist - Internet World
c/o KRYPTON NEON 34-43 Vernon Blvd Long Island City, NY 11106
      Ph: 718-728-4450   Fx: 718-728-7206  Email: kenny@neonshop.com
      http://www.neonshop.com    gopher://gopher.panix.com:70/11/nyart