4 wire connection

Discussion in 'The Projects Forum' started by chuackl, Sep 27, 2013.

  1. chuackl

    Thread Starter New Member

    Sep 26, 2013
    The 4 wire connection method is generally use in measuring low resistance. However, can we use opamp as well to compare a resistor(in term of miliohm) to standard resistor(miliohm) to judge whether the resistor over or under the standard resistor? Since the open loop gain of opamp is huge, therefore able to detect even very small difference in both input value(provided i figure out how to solve the problem of error due to point contact and gain error)
  2. wayneh


    Sep 9, 2010
    Yes. Or you could use two comparators to construct a window comparator. The window would be the allowable range for a "good" resistor, and the output would be a pass/fail.