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Parasitic capacitance influence on lead voltage

  1. Apr 20, 2015 #1
    V' changes over time. How can I determine the influence from parasitic capacitance (~50 pF) on V?
    R wire ~ 100 ohm. If I need to read data (V' can change rapidly) from this at 50hz, does it influence reading accuracy? How can I determine values from which I need to be careful when reading data (when τ=RC>0,02sec ?)

    https://lh5.googleusercontent.com/YxtTJvFj8vYphq43bW3FTw0ygk7D0WOJPVmzetsrsRsbclgyXy9ErGz6jA=s300 [Broken]
     
    Last edited by a moderator: May 7, 2017
  2. jcsd
  3. Apr 20, 2015 #2
    This will all depend on how V' is changing over time. Is it a sine wave? Then the solution will be relatively straightforward to calculate. If V' changes arbitrarily, it won't be nearly as easy :)
     
  4. Apr 20, 2015 #3
    V' changes chaotically.
     
  5. Apr 20, 2015 #4
    The problem is, all the easy tools that exist for analyzing circuitry presume a steady state, or at least a "periodic steady state".
    What you have there is a type of RC circuit, and the only way to deduce the output from an arbitrary input is by solving the differential equation of that system.
    For more:

    http://en.m.wikipedia.org/wiki/RC_circuit
     
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