Loading ...
Sorry, an error occurred while loading the content.
 

RE: [VLF_Group] 100 GOhm resistor for ELF/ULF antenna buffer

Expand Messages
  • David VanHorn
    ... Bob Pease from National Semi talks about Teflon a lot. It causes problems by storing charge internally. It s actually TOO good. Glass and Air are your
    Message 1 of 33 , Mar 1, 2004
      At 08:22 PM 2/29/2004 -0500, W1EOF wrote:

      >Infinity-schminity... lol We regularly measure up to 10^12 (1 million
      >megohms). It takes good equipment and careful procedures that's all. In the
      >automated tester I designed back in the 80s we used an electrometer IC from
      >Analog Devices in a picoammeter configuration. The feedback resistors were
      >glass-bodied from Victoreen. Contanimation can be a problem, we used an
      >industrial form of alcohol to keep it all clean. Next you start to have
      >problems with stuff like triboelectric interference from your teflon
      >insulators. It gets interesting!

      Bob Pease from National Semi talks about Teflon a lot.
      It causes problems by storing charge internally. It's actually TOO good.
      Glass and Air are your friends. :)

      Everything in these circuits has to be kept more than surgically clean.
    • Percy Jones
      Hi Wolf, Ok on the spluttered film inside the bulb, I think that is a more likely path rather than a water film outside the bulb. It was an interesting thread
      Message 33 of 33 , Nov 13, 2008
        Hi Wolf,
        Ok on the spluttered film inside the bulb, I think that is a more
        likely path rather than a water film outside the bulb. It was an
        interesting thread for me even though it was a bit off topic, sorry
        about that. But I have heard of at least one study trying to correlate
        the fair weather field with world wide VLF spheric activity.
        I found some 18G resistors on Ebay for reasonable $, but nothing
        higher. I might see if I can pick up an old Keithly electrometer, it
        could turn out to be cheaper than building something.

        Percy KF2AT
      Your message has been successfully submitted and would be delivered to recipients shortly.