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Negative Resistance Definitions.

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  • Harvey Norris
    negative resistance In electrical circuits, static resistance is the ratio of the voltage across a circuit element to the current through it. However, the
    Message 1 of 1 , Jun 19, 2005
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      negative resistance
      In electrical circuits, static resistance is the ratio
      of the voltage across a circuit element to the current
      through it. However, the ratio of the voltage to the
      current may vary with either voltage or current. The
      ratio of the change in voltage to the change in
      current is known as dynamic resistance.

      Circuit elements composed of certain materials exhibit
      the property that, over certain voltage ranges,
      current is a decreasing function of the voltage. This
      range of voltages is known as a negative resistance
      region.

      It may be more correct to say that a circuit element
      has a negative differential resistance region than to
      say that it exhibits negative resistance because even
      in this region the static resistance of the circuit
      element is positive, while it is more precisely the
      slope of the resistance curve which is negative.

      [HDN/ well it takes awhile to think about that one,
      but acccording to the slope definition, we plot V vs
      R, but with SrFe heating the resistance goes down with
      the impressed voltage; With the additional
      complication that when lower resistances of the load
      are reached with the highest heats; that low ohmic
      load will also drop the output voltage of the source
      powering it; according to maximum power transfer laws:
      similar to action of that load being placed as an
      interphasal resonant one, where impedance matching
      then becomes possible.]

      An example of an electronic component exhibiting the
      negative differential resistance region is the tunnel
      diode. Such a device, when biased into its negative
      differential resistance region, will act as an
      amplifier.

      In conformance with the known law of conservation of
      energy, a plot of the negative differential resistance
      region of a component cannot normally pass through the
      origin.

      Some work by Professor Deborah Chung at the University
      of Buffalo has discovered a composite configuration of
      carbon nanotubes which appears to exhibit anomalous
      results which resemble a static negative resistor.
      However, the physical interpretation of this
      observation is still controversial.

      Gabriel Kron, while a scientist for General
      Electric,[1]
      (http://www.quantum-chemistry-history.com/Kron_Dat/KronGabriel1.htm)
      is thought to have built a negative resistor for the
      US Navy's "Network Analyser" (probably an analogue
      computer) in the 1930s; but as it was a military
      project no details have ever come to the public.[2]
      (http://www.cheniere.org/misc/kron.htm) One of his
      papers does contain a blasé "Although negative
      resistances are available for use with a network
      analyzer..."[3]
      (http://www.quantum-chemistry-history.com/Kron_Dat/Kron-1945/Kron-PR-1945/Kron-PR-1945.htm)

      Another concept of negative resistance exists in the
      domain of radio frequency antenna design. This is also
      known as negative impedance. It is not uncommon for an
      antenna containing multiple driven elements to exhibit
      apparent negative impedance in one or more of the
      driven elements.

      HDN/ To further delve into this concept of negative
      impedance; we further classify the meaning of positive
      impedance; which is simply the sum effects of both the
      inductance and the resistance upon the currents of the
      load. A positive impedance then means that the
      currents will be less then what would exist if the
      inductance were not present where Ohms Law V=IR then
      applies. What a negative impedance may appear to do;
      dependent on how we measure the circuit conditions; is
      to provide for a measurement whereby instead of the
      impedance detracting from the possible current
      delivery by ohms law amount; we find current above and
      not below that amount.

      This happens when three adjacent spirals of high
      mutual induction are attached to the alternator three
      phase/ and wired in WYE, where the currents of each
      phase must return on another phase. The voltage
      mesurement of each WYE section is actually a delusion
      brought upon by mutual induction; and when measuring
      the V/I ratio for each wye segment, the measurement
      shows a conduction above that possible by ohms law.

      However when the Delta voltage measurements are
      made,of that same WYE load application; the delusion
      is made apparent. The same system of adjacent spirals
      in three phase does not yeild a negative impedance
      measurment when wired in Delta. But what does occur is
      impedance cancellation by three magnetic fields all
      simultaneously summing to zero at any instant of time;
      a sort of three phase scalar magnetic compression.
      Each of these magnetic fields induces currents on its
      neighbors; and those currents are in the same
      direction as the currents made from its line
      connections. However APPARENTLY even though both of
      these sources of emf make currents in the same
      direction, the inductive source appears to have an emf
      opposite to that of the line connected source, so that
      when the net difference is noted by that voltage
      mesurement of the segment in WYE, we find that the
      inside voltage measurements are much smaller then
      would should exist by mesurements on the outside delta
      voltage sources; where this is normally a 1.7 ratio,
      but now this has been formed into a higher ratio.

      The further idiosychasies involved here is that a
      single wind of these segments is only 1/4 of the
      amount used for maximum energy transfer, therefore
      that load without impedance becomes an overload
      circuit placed upon the alternator. However this
      simply means that more careful field current
      adjustments need be made for making the circuit
      conditions. The fact that each winding is making
      additional currnt on its neghboring phases also means
      the ratio of R(int)/ R(load) is being driven even
      further in the overload state.
      HDN


      Tesla Research Group; Pioneering the Applications of Interphasal Resonances http://groups.yahoo.com/group/teslafy/
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