HIGH MEG REISTORS

[John Allen W4GQT]

Alex,

Victoreen has been "bought out" by another company, and I can't remember the 
name. If you can't find it, let me know and I'll check an invoice and let you 
know. If I remember correctly, they do have a minimum order amount, I think 
$100.00. I order high value resistors from them on a regular basis for equipment 
that we build for monitoring static electrical levels in textile and chemical 
plants.
    There is an article in an old book by "Scientific American" called " " 
the Amateur Scientist". It is of interest for building vacuum tube systems for 
monitoring "spherics" and the earth's potential gradient (~+100 volts/meter in 
fair weather). It can go as high as 20,000 to >100,000 volts/meter during 
thunder storms.
    Even the best vacuum tube electrometers are not very reliable w/100 
Gigahms in their grid circuits. Drift is a constant problem if you are monitoring 
with a chart recorder or an 
A-D & computer for data logging. Hum pick up is an even bigger problem. There 
are solid state/ ICs that run rings around the very best electrometer tubes 
for stable performance.

Let me know if you have any questions that i might be able to answer for you.


Good luck w/ your project.  73 John Allen   W4GQT

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