HP 4194 Impedance Analyzer for Resistivity Measurements

Discussion in 'The Projects Forum' started by mwfarooqi, Oct 29, 2013.

  1. mwfarooqi

    Thread Starter New Member

    Oct 29, 2013
    Hi All
    Please be aware that without any detailed knowledge about electronics and circuitry, I may be asking a very obvious question. At this moment, I want to get my basics right.

    I am looking to measure the surface resistivity of an insultor tube built as as per ASTM D257 standards. Historically, I have very conveniently used a Voltmeter, applied a 500V voltage and got the rading on the meter in MΩ. Anything above 550 MΩ was considered to be infitnite resitance and good insulator. However, now I have a need to get a more accurate answer above this maximum readadble value of our voltmeter for the resitivity acorss the surface of a part. Just casually speaking to someone who is from the electronics field, was informed that an Impdance Analyzer that we have sat in the office under dust, would be able to give you a numerical value (if greater than 550 MΩ).

    1. First of all, is this possible?
    2.Secondly how would I do the programming and circuitry to this. What would I require?

    Would be greateful for a swift reply.

    Many thanks.
  2. Tesla23

    Senior Member

    May 10, 2009
    The HP4194 measures impedance in a 50Ω system and as such has great difficulty measuring impedances of MΩ. See the user manual http://cp.literature.agilent.com/litweb/pdf/04194-90011.pdf on page 1-10 which shows the accuracy degrading rapidly above 200kΩ.

    The 4194 is a great instrument though, just not for measuring MΩ. It's a pity to leave it under dust.