In a circuit, an electric field is produced from a circuit element providing a voltage source. Electrons flow through the circuit undergoing collisions which provide a resistive force to the electrons such that the drift velocity is a constant. Impurities in the crystalline structure and thermal motion of constituent atoms are responsible for this resistive force. The description of impurities reminds me of friction on the microscopic scale.

My question is, is there a minimum amount of electric field/voltage required to initially accelerate the electrons to overcome the impurities? Such that one can have a resistive analogy to static/kinetic coefficients of friction?

Considering the definition of resistance from Ohm's law, I'm unsure about this analogy. If a minimum voltage needs to be applied in a circuit for current to flow, then the circuit resistance below this value is always infinity, such that in practice, we always discuss the 'kinetic' resistance.

  • $\begingroup$ There is no minimum value of voltage needed for a current to flow, even a tiny voltage can produce a tiny current $\endgroup$ Commented Nov 23, 2021 at 12:48
  • $\begingroup$ Always remember that any analogy in physics has its limits where the analogy breaks down. $\endgroup$
    – Jon Custer
    Commented Nov 23, 2021 at 14:23
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    $\begingroup$ When mechanical friction is used as an analog to electrical resistance it is kinetic friction $\endgroup$
    – Bob D
    Commented Nov 23, 2021 at 14:55

1 Answer 1


There is no analog to static friction in Ohm’s law. However, a diode could be somewhat analogous to a device with static friction. Unfortunately, the analogy is a little odd because the diode’s “static friction” is direction dependent. It is small in one direction and large in the other.

Generally, mechanical systems are more complicated than electrical circuits. So it is rarely worthwhile to try to make analogy of an electrical circuit as a mechanical device. However, the opposite can occasionally be useful. Sometimes it is helpful to analyze a mechanical system by using a circuit which is equivalent to the mechanical device:


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    $\begingroup$ @jamie1989, there is a tool which you can use to derive an electrical circuit-like representation of a mechanical system: the power bond graph. See karnopp & rosenberg, System dynamics: a unified approach. $\endgroup$ Commented Nov 23, 2021 at 19:29
  • $\begingroup$ Won't two antiparallel diodes do the job of modelling static friction ? $\endgroup$ Commented Jun 21, 2023 at 11:58

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