Electrical conductivity in granular media and Branly’s coherer: A simple experiment

  title={Electrical conductivity in granular media and Branly’s coherer: A simple experiment},
  author={Eric Falcon and B. Castaing},
  journal={American Journal of Physics},
We show how a simple laboratory experiment can illustrate certain electrical transport properties of metallic granular media. At a low critical external voltage, a transition from an insulating to a conductive state is observed. This transition comes from an electro-thermal coupling in the vicinity of the microcontacts between grains where microwelding occurs. Our apparatus allows us to obtain an implicit determination of the microcontact temperature, which is analogous to the use of a… Expand

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