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Resistor - four terminal device

  1. May 20, 2007 #1
    I've read of resistors being referred to as four terminal devices, and capacitors being referred to as 3 terminal devices, can anyone explain this? or point me to a source that explains it, I can't find anything about it online.
     
  2. jcsd
  3. May 20, 2007 #2
    I've never heard that, transistors are 3 terminal devices.
     
  4. May 20, 2007 #3

    chroot

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    Well, I'm an integrated circuit designer with a master's in electrical engineering and almost ten years of industry experience -- and I've never heard of such things either.

    - Warren
     
  5. May 20, 2007 #4
    One day I want to be able to say that.
     
  6. May 20, 2007 #5

    ranger

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    Could you be referring to a Four-terminal current sense resistor?
    http://www.koaspeer.com/resistors.asp?part=24
    3-terminal capacitor (US Patent 5040094)
    http://www.google.com/patents?id=p7UdAAAAEBAJ&dq=3+terminal+capacitor

    Where did you read it from?
     
  7. May 26, 2007 #6
    I'm still not clear on this, but its not that important. It was a past paper question for one of the modules I am doing, I believe it was referring to some sort of resistor where there were very low voltages being measured, current was driven through two of the terminals and the voltage measured across the other two terminals.

    There was a small paragraph about it in "Electronic Instrumentation and Measurements" by David A. Bell
     
  8. May 26, 2007 #7
    Maybe you mean that bipolar junction transistors (which have resistive coupling between the base and conduction channel) are three terminal devices while field effect transistors (which have capacitive coupling between the gate and conduction channel) are four terminal devices.

    I could be a troll and wait for someone to say "you're wrong, FETs only have three terminals: the gate, the source and the drain". Instead, I will preemptively remind everyone that a FET also has a substrate which must be connected to ground... therefore, it is technically a four terminal device.
     
  9. May 26, 2007 #8

    chroot

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    Perhaps you're thinking about the apparatus for measuring resistivity, ineedmunchies. It does indeed involve four terminals, but it's not a "resistor."

    - Warren
     
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